Author Topic: Tektronix THS7xxx Scope Hack/Teardown/Discussion - FW 1.16 found  (Read 73792 times)

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Offline Zucca

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Hello,

FW UPDATE

Thanks to superman13

https://www.eevblog.com/forum/testgear/tek-ths720a-portable-scope-teardowndiscussion/msg1480909/#msg1480909

Thanks to yaromka, here the FW1.16

FW 1.16

HACK

Thanks to TurboTom

https://www.eevblog.com/forum/testgear/tek-ths720a-portable-scope-teardowndiscussion/msg1073777/#msg1073777

SCHEMATICS

Thanks to R_G_B_

https://www.eevblog.com/forum/testgear/tektronix-ths700-tekscope-component-level-information-package-and-schematic/

ORIGINAL POST ON THS720A

I just got a Tek THS720A on Ebay. I like this device a lot, there is isolation everywhere: each scope CH and also the DMM input are isolated from each other. For a portable scope a good isolation is a must. The price range is much affordable than a Fluke scope which cost an arm and a leg.

It is a 100Mhz scope 2 CH, see some specifications here:

Quote
Oscilloscope
Bandwidth    100-MHz Digital Real Time    
Sample Rate    500 MS/s each channel
Time/Division Range    5 ns to 50 s/div
Channels    Two
Sensitivity    5 mV to 50 mV/div (to 500 V/div with 10X probe)
Vertical Resolution    8 bits
Record Length    2500 points
Time Bases    Main or delayed run after
Display Modes    Vectors, dots, vector accumulate, dot accumulate, YT, XY
Triggering    Main only, edge, pulse, video lines, video fields
Acquisition Modes    Sample, envelope, average, peak detect
Autorange    Controls volts/div, time/div, trig level and acquisition mode
Waveform Maths    Ch1 + Ch2, Ch1 - Ch2, CH1 x Ch2
Cursors     H bars, V bars, paired (volts @ time)
Measurements    Pk-Pk, mean, min, max, rms, +width, -width, frequency, period, +duty, -duty, rise, fall

Multimeter
Resolution    4000 counts, 3.75 digits
DC Volts    400 mV-880 V True RMS
AC Volts    400 mV-640 V True RMS
Resistance    400-40 MW (with continuity beeper)
Diode Test    Up to 2 V
Other DMM Features    Autorange, true rms, average meas., hold, statistics, Min/Max Alarm

General Features
NV Storage    10 waveforms, 10 setups, 100 DMM saved screens
User Interface    Simplified TDS 320 with pop-up menus
I/O    RS-232 (to 38.4K baud)
Chassis    Battery Operated, hand-held
Reliability    Calculated MTBF 20,000 hours @ 25 degrees Celsius

The device needs 502mA (400mA when the LCD back light is off) from the 12VDC jack with no battery connected. In standby the current goes down to 8.45mA. With 5.5VDC on the 12VDC Jack the device was still on, but I did not went below that limit because I heard some funky noises (surely some switching DC/DC converter was screaming on me).

Regarding the battery, it is a 4.8V Ni-Cd (4xSize C) 2.8Ah. At 4.8V Battery voltage the device is asking 1.2A (1A when the back light LCD is off) to stay on. "Low Battery" warning appears at 4.6V. The power cuts off at 4.2V. In standby the current is about 176µA.
I performed a full discharge and then I charged it for 16 hours at C/10 280mA. Afterwards I did discharge test @1.2A CC:


 
not bad, 2.71 Ah Capacity and simulated 2:14 Lifetime to reach 4.2V (power cuts off).

The battery charger works like this (according to my reverse engineering):

VBatt <3.5V: CC charge at 110mA
VBatt >3.8V: charge current [mA]= -187.27*VBatt[V]+1283.63
3.5V<VBatt <3.8V: Previous state

Unfortunately It has a problem, see here for details
https://www.eevblog.com/forum/repair/tek-ths720a-thinks-there-are-110v-on-the-input-but-there-is-just-a-50-ohm-r/msg490731/
so I decided to tear it down. I hope I can fix it.

Here we go:

Under the front panel, solid metal panel for EMI with on top the the flex keyboard


below we can find the inverter board for the back light and the LCD


inverter top side


inverter bottom side


Nice touch, very practical to remove the rear battery case


without the inverter and the LCD


rear panel with battery holder


Battery contacts, in this way you can´t use regular 4 Size C batteries


main board bottom side; clearly CH 1, CH 2 and DMM are isolated


CH 1 circuit bottom side


DMM input bottom side


central digital stuff, bottom side


LCD output and power supply circuit, bottom side


Main board top side, funny those two transformer for each channel


Power supply, top side


CH circuits, I don´t want to desolder the cans yet


Interesting DMM input, extra PCB piece above the main board for EMI?


Main processor stuff, top side. Debug/Service port on the top?


Todo List:

1) Fix the offset Problem in CH1
2) Upgrade FW from 1.14 to 1.16, any advice? Looks like the FW is in U1 (from Memory_Erasure_071181500.pdf):

Quote
156--7404--01

U1

IC, MEMORY; CMOS, FLASH ;1MEG X 8, 5.0
VOLT--ONLY, SECTOR ERASE;
AM29F080--120EC , 40PIN TSOPT&R

Flash memory which contains instrument
firmware, current setup, saved setups, saved
waveforms, saved data, waveforms, and
calibration constants.

3) Calibration


Possible Mods:

Does anybody has the schematics?

1) Build a switch to manage the back light LCD (turn off and on the inverter board). If there is enough ambient light, there is no need to use that energy. Why Tektronix did not built a back light switch?

2) Reverse Engineering the power supply and and battery charge circuit. Upgrade to Li ion by using three of those ones:
http://www.battery-matrix.com/3-2V26650-3300mah-LIFEPO4-IFR26650-3300mah.html
which just fit perfectly in the 4xSize C battery compartment. Target is to achieve a battery life between 2x and 3x than the current one.

3) Develop a 4 leds battery gauge.

------

High resolution pictures here:

http://postimg.org/gallery/6dfgsp1i/

Sorry I did everything with an IPhone 5, a Canon 60D will be in my hands soon.

« Last Edit: August 13, 2019, 06:39:19 am by zucca »
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Offline BravoV

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #1 on: August 11, 2014, 02:59:33 am »
Congratulation on the score and nice tear down.  :-+

Glad I can see the inner gut of this scope cause all this time I was curious how it looks like inside, thank you !  :clap:

Too bad, sorry to hear it has problem, mine doesn't have that. Also does it came with the P6117 probes ? These P6117 probes are designed and built specifically for isolated probing, and its hard to find and quite expensive even its used.  :'(

Btw, I made a discussion thread when I bought my THS710A -> HERE while ago.

About the NiCd battery pack, since the original Tek's batt pack is stupidly expensive  >:(, I modded 3 pieces of AA->C adapter, and made the battery pack for it, and used Eneloop Pro 2450 mAH batteries. It performs a lot better than that shitty NiCd cells, cause these NiCd is well known to have a really high self drain, mine will be fully discharged when left unused just for less than 2 weeks.  :--

Too bad currently I don't have the modded battery pack with me, but it looks very similar to Jay's one at above pointed THS710A discussion thread, but with slightly modded with a long cut across the battery pack to allow the AA batteries to be released as the adapters have hinges. Its very handy as I can charge each of them properly in externally NiMH charger Maha MH-C9000. Also the standard slow charging method at the scope is using low current & overnight method which is not suitable for NiMh cells. Attached below photo shows my other spare AA to C adapters that I planned to build another battery pack for my THS710A soon.
« Last Edit: August 11, 2014, 03:04:43 am by BravoV »
 

Offline Zucca

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #2 on: August 11, 2014, 03:58:50 am »
Also does it came with the P6117 probes ? These P6117 probes are designed and built specifically for isolated probing, and its hard to find and quite expensive even its used.  :'(

Btw, I made a discussion thread when I bought my THS710A -> HERE while ago.

Very nice thread! Thx!

One P6117 was there, and I already got a P5102 65$, eBay auction: #111429274915, as a second probe. Yes I am stupid I should had wait to see if my unit can be fixed or not.

Regarding the Battery, your solution is very reasonable. Still I would like to investigate the possibility to fit a Li ion with a properly charge system (inside the unit or outside through the 12VDC).
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Offline marshallh

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #3 on: August 11, 2014, 04:21:46 am »
Regarding the firmware if I still had my ths720a I would dump it for you. However it may be possible to upgrade with a PC serial port connection app. You'll have a build a cable first and run the software in a VM

Verilog tips
BGA soldering intro

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Offline Zucca

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #4 on: August 11, 2014, 12:54:03 pm »
Thank you marshallh, it would be fantastic. I would love to get my hands on the 1.16 FW (according to my investigation this is the latest released FW by Tektronix) and surely a lot of people out there will love that.

However it may be possible to upgrade with a PC serial port connection app. You'll have a build a cable first and run the software in a VM

I have the RJ-45 to Sub-D9 RS232 cable, I mean this one:
http://www.tek.com/support/faqs/what-pin-out-ths700-rj45-connector-rs232

What app are is the one you are talking about? I searched in the www but no hope to find anything related to your suggestion. Is a VM a Linux Virtual Machine? If yes I have a FreeBSD box which should do the job.
« Last Edit: August 11, 2014, 12:57:19 pm by zucca »
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Offline SoundTech-LG

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #5 on: August 20, 2014, 06:19:43 pm »
Nice teardown photos!

I also did the Eneloop Pro  NiMh mod. Blows NiCd out of the water!!!
 

Offline Zucca

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Offline nixxon

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #7 on: June 10, 2015, 02:05:03 pm »
Regarding the firmware if I still had my ths720a I would dump it for you. However it may be possible to upgrade with a PC serial port connection app. You'll have a build a cable first and run the software in a VM

I bought your THS720A, marshallh . If it is of interest, I could try to dump the firmware. I have not figured out the serial connection yet, though.

What is the difference between FW 1.14 and 1.16?

I also have the Service Manual for the THS 710 & THS 720 (no "A") TekScope 070-9246-03 if it is of interest to anyone the get a copy.
 

Offline Zucca

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #8 on: June 10, 2015, 02:47:24 pm »
What is the difference between FW 1.14 and 1.16?

http://www1.tek.com/forum/viewtopic.php?f=5&t=6499&sid=877fe8805d6d2c8dd8540e62e3f2365a

looks like we (you and me) are not alone, but the question is still open.

If it is of interest, I could try to dump the firmware. I have not figured out the serial connection yet, though.

Maybe the schematics can help us....
I am still interested, unfortunately I have to close up other projects before to continue this one. Keep us posted please.
« Last Edit: June 10, 2015, 03:06:39 pm by zucca »
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Offline R_G_B_

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #9 on: June 10, 2015, 07:41:58 pm »
R_G_B
 

Offline R_G_B_

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #10 on: June 10, 2015, 07:45:07 pm »
What is the difference between FW 1.14 and 1.16?

The firmware version 1.6 is for the 720P which  has the power measurement option.

R_G_B

R_G_B
 

Offline nixxon

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #11 on: June 10, 2015, 08:31:52 pm »
sieral connection pin out can be found here:


http://www.tek.com/support/faqs/what-pin-out-ths700-rj45-connector-rs232

I have tried the somewhat ambigous pinout you link to (at tek.com/support) and multiple other pinout variants, unfortunately with no success. If anyone has a working THS700-series rj45-DB9* cable and could measure all pins at both ends, I would be grateful. Anyone?

*DB-9 is actually a DE-9 (9-pin connector with an E size shell), according to http://en.wikipedia.org/wiki/D-subminiature
« Last Edit: June 11, 2015, 06:44:30 pm by nixxon »
 

Offline R_G_B_

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #12 on: June 10, 2015, 09:31:21 pm »
R_G_B
 

Offline R_G_B_

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #13 on: June 10, 2015, 09:52:29 pm »
,
« Last Edit: June 10, 2015, 10:19:46 pm by R_G_B_ »
R_G_B
 

Offline R_G_B_

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #14 on: June 10, 2015, 10:48:55 pm »
p2 Orange D8
P3 Black  D4
p4 RED    D3
P5 GREEN  D1
P6 Yellow D9
P7 Blue   D2
P8 Brown  D8

R_G_B
R_G_B
 

Offline R_G_B_

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #15 on: June 11, 2015, 07:54:15 am »
R_G_B
 

Offline Zucca

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #16 on: June 11, 2015, 07:59:32 am »
Thanks R_G_B, I was just going to double check that. It looks like the 1.16 goes also on the THS720a too.

Oh man I need a day with 48 hours to work on all my projects... can´t wait to start again on this one.
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Offline nixxon

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #17 on: June 11, 2015, 09:57:53 am »
p2 Orange D8
P3 Black  D4
p4 RED    D3
P5 GREEN  D1
P6 Yellow D9
P7 Blue   D2
P8 Brown  D8

R_G_B

Is the left column in your table ("p2" etc.) the RJ45 pins and the right column ("D8" etc.) the DB9 connector pins?
Is your table based on a continuity test of a working cable?
If so, the actual wiring of a working cable is totally different from the answer on Tektronix FAQ : http://www.tek.com/support/faqs/what-pin-out-ths700-rj45-connector-rs232

I have illustrated a cable that I made a while ago that doesn't work, based on the Tektronix FAQ.
EDIT: THE RJ45 CONNECTOR IN THE ILLUSTRATION HAS WRONG A REVERSED PIN NUMBERING.

When I was trying to get this to work a year or two ago, I tried various pinouts. Based on a post on the tektronix forum, I also tried to swap the DCD and DSR pins of the RJ-45 connector (pins 1 and 2). It did not work.
At http://www1.tek.com/forum/viewtopic.php?f=5&t=5449 JeanPaul wrote:

Quote
Having plan to communicate with my recently bought (used) THS720 Std, unfortunately delivered without needed RJ45 to DB9 adapter, Tek part 103-0403-00, I have to build one myself.
In short, I’m not very sure said Tek’s information is correct, because therein two RS-232 signals, DCD and DSR, might be changed. I have reviewed following information precisely.
As the RJ45 pinout on page 1-8, table 1-3 of Tek’s Service Manual THS 710 & THS 720 TekScope, document no. 070-9246-03, seems to contradict the EIA-561 standard concerning RS-232.
Found two resources about said standard:
http://www.interfacebus.com/Design_Connector_RS232.html
/EIA-232 Bus Pin-Out
/RS232 RJ-45 Connector Pin Out
http://wiki.secretlab.ca/RS232_EIA-561_ ... DB9_wiring
/EIA-561 RJ45 to DB9 adapter pinout
Otherwise, said Tek manual is right as there is a reason said signals are wired as shown indeed. I would be happy if Tek could understand my point of doubt and clarify that point.
Having clarified Tek's RJ45 pinout is right, else which is, would help. A wiring diagram of the whole RS-232 connection even would be great. Thanks in advance.
« Last Edit: March 09, 2018, 07:50:19 pm by nixxon »
 

Offline Zucca

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #18 on: June 11, 2015, 10:05:44 am »
Is your table based on a continuity test of a working cable?

I have a tested OK cable, let me know if you need the pinouts...
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Offline nixxon

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #19 on: June 11, 2015, 10:32:51 am »
Is your table based on a continuity test of a working cable?

I have a tested OK cable, let me know if you need the pinouts...

I would be really be happy if you could measure your working cable and present your findings here  :)
 

Offline R_G_B_

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #20 on: June 11, 2015, 11:29:18 am »
P1 Grey    D7
p2 Orange D8
P3 Black  D4
p4 RED    D3
P5 GREEN  D1
P6 Yellow D9
P7 Blue   D2
P8 Brown  D8

R_G_B
Is the left column in your table ("p2" etc.) the RJ45 pins and the right column ("D8" etc.) the DB9 connector pins?
Is your table based on a continuity test of a working cable?
]
Yes to all your questions    with the D connector pin numbers in reverse order to the tektronix illustration  R_G_B
« Last Edit: June 11, 2015, 11:50:23 am by R_G_B_ »
R_G_B
 

Offline nixxon

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #21 on: June 11, 2015, 11:33:35 am »
p2 Orange D8
P3 Black  D4
p4 RED    D3
P5 GREEN  D1
P6 Yellow D9
P7 Blue   D2
P8 Brown  D8

R_G_B
Is the left column in your table ("p2" etc.) the RJ45 pins and the right column ("D8" etc.) the DB9 connector pins?
Is your table based on a continuity test of a working cable?
]
Yes to all your questions R_G_B

Great! Thanks :D  Is the numbering of both connector pins the same as shown in my illustration 4 posts above?
« Last Edit: June 11, 2015, 11:35:40 am by nixxon »
 

Offline z01z

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #22 on: June 11, 2015, 11:42:28 am »
Not likely, as D5 (GND) is missing. There should be a line P4-D5.
However there is P5-D1, which indicates that both connectors are numbered in reverse order.

Edit: there is also a RJ-45 Connector pinout in the user manual:
1 DCD
2 DSR
3 DTR
4 GND
5 RXD
6 TXD
7 CTS
8 RTS
« Last Edit: June 11, 2015, 11:46:53 am by z01z »
 

Offline nixxon

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #23 on: June 11, 2015, 12:03:03 pm »
Not likely, as D5 (GND) is missing. There should be a line P4-D5.
However there is P5-D1, which indicates that both connectors are numbered in reverse order.

Edit: there is also a RJ-45 Connector pinout in the user manual:
1 DCD
2 DSR
3 DTR
4 GND
5 RXD
6 TXD
7 CTS
8 RTS

When I reverse R_G_B_'s numbering of both connectors, the measured pins by R_G_B_ matches the info on the Tek FAQ. Pin 8 (on RJ-45) seems not to be connected though.

So, when unscrambled the R_G_B_ values are:

RJ-45 --> DB-9
1 -------> 7
2 -------> 4
3 -------> 6
4 -------> 5
5 -------> 3
6 -------> 2
7 -------> 7
8 -------> not connected

There should be continuity between RJ-45 pins 1 and 7
Could anyone please check if there is continuity between DB-9 pins 1 and 8?
And if RJ-45 pin 8 is connected to DB-9 pin 1 and/or pin 8?
« Last Edit: June 11, 2015, 07:23:28 pm by nixxon »
 

Offline nixxon

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #24 on: June 11, 2015, 07:10:23 pm »
Thanks R_G_B, I was just going to double check that. It looks like the 1.16 goes also on the THS720a too.

Oh man I need a day with 48 hours to work on all my projects... can´t wait to start again on this one.

My THS720A info screen says "Version: FV:v.1.16", "Wed Dec 16 11:48:07 PST 1998".

If it is possible to dump firmware by the RS-232 connection, I will give my RJ-45 <---> DB-9 cable another try when I get back home on Sunday after sailing The Færderen* 2015  - hmm, I wonder if the King** will participate this year...

*the world's largest overnight regatta: http://www.færdern.com/index.php/nb/home-english
** King Harald V of Norway http://en.wikipedia.org/wiki/Harald_V_of_Norway
 

Offline HighVoltage

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #25 on: June 11, 2015, 07:19:44 pm »
I used these scopes a lot, sometimes more than one, to capture signals in vehicles.
But it was not so easy to capture the screen data and the official Tek software sucked big time.

I found a small piece of software once to make a relative fast screen shot to .JPG from the RS232 port.
It worked very well.
If anyone is interested, let me know and I will upload it somewhere.

The only problem hardware problem with these scopes are the rechargeable batteries
The original is really expensive and -I think- not even available any more.

There are 3 kinds of people in this world, those who can count and those who can not.
 

Offline Fraser

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #26 on: June 11, 2015, 07:26:58 pm »
@Nixxon

I am currently en route to Oslo aboard Fred Olsen's MS Balmoral. We arrive 09:30 tomorrow morning for the Regatta and stay overnight .... looking forward to seeing all the boats  :)

Aurora
 

Offline nixxon

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #27 on: June 11, 2015, 07:44:04 pm »
@Nixxon

I am currently en route to Oslo aboard Fred Olsen's MS Balmoral. We arrive 09:30 tomorrow morning for the Regatta and stay overnight .... looking forward to seeing all the boats  :)

Aurora

That is cool. I wish you a nice trip to Oslo. According to marinetraffic.com, you and MS Balmoral are currently at position N57º47', E008º33.5' South East of Kristiansand, heading 35º at a calm 11.5 knots. Tomorrow there will be many sails on the fjord. We will sail by MS Balmoral beside Akershus-Fortress between 14:30 and 14:39 as we try to get a good starting position for our class start at 14:40. The starting line is just to the West of your ship and East of Aker Brygge wharf: http://www.visitoslo.com/en/activities-and-attractions/attractions/?TLp=282572&Aker-BrYgge-wharf
« Last Edit: June 11, 2015, 08:30:17 pm by nixxon »
 

Offline R_G_B_

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #28 on: June 11, 2015, 09:52:57 pm »
If its possible to dump the firmware from the 720p so that you get the additional power measurement options if at all possible?


The firmware for the THS720P is shown on the screen as:


THS720P version 1.6 wed Dec 16 11:48:07 1998

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Offline Zucca

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #29 on: June 12, 2015, 07:43:51 am »
If it is possible to dump firmware by the RS-232 connection, I will give my RJ-45 <---> DB-9 cable another try when I get back home on Sunday after sailing The Færderen* 2015  - hmm, I wonder if the King** will participate this year...

That would be cool, moreover I want to try to desolder U1 and dump it out... Finally Weekend is here... and I will work on this.

Z
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Offline R_G_B_

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #30 on: June 12, 2015, 04:24:35 pm »
There s a port on the actual PCB underneath the touch pad along side the inverter board have you seen it?

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Offline z01z

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #31 on: June 13, 2015, 04:28:14 pm »
When I reverse R_G_B_'s numbering of both connectors, the measured pins by R_G_B_ matches the info on the Tek FAQ. Pin 8 (on RJ-45) seems not to be connected though.

So, when unscrambled the R_G_B_ values are:

RJ-45 --> DB-9
1 -------> 7
2 -------> 4
3 -------> 6
4 -------> 5
5 -------> 3
6 -------> 2
7 -------> 7
8 -------> not connected

There should be continuity between RJ-45 pins 1 and 7
Could anyone please check if there is continuity between DB-9 pins 1 and 8?
And if RJ-45 pin 8 is connected to DB-9 pin 1 and/or pin 8?
I've checked my cable and it is exactly the same as in the Tek FAQ, except that the RJ45 is reversed. As if the layout pictured the RJ45 socket in the scope, from the outside - or the plug looked at from above with pins on the top, the cable on the bottom and the locking tab underneath and not from the front as the picture shows.
 

Offline HighVoltage

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #32 on: June 13, 2015, 04:49:27 pm »
This is the flat-cable and adapter, that came with my THS-720P
Pin 9 is not connected at all.

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Offline nixxon

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #33 on: June 15, 2015, 08:12:03 am »

I've checked my cable and it is exactly the same as in the Tek FAQ, except that the RJ45 is reversed. As if the layout pictured the RJ45 socket in the scope, from the outside - or the plug looked at from above with pins on the top, the cable on the bottom and the locking tab underneath and not from the front as the picture shows.

That is very interesting news. If you are right, there is no wonder why my cable didn't work.

Now I will have to make a new cable with connectors that are wired like this:

RJ-45 --> DB-9
8 -------> 7
7 -------> 4
6 -------> 6
5 -------> 5
4 -------> 3
3 -------> 2
2 -------> 7
1 -------> 1 & 8


EDIT: It seems that I have managed to base my earlier illustration (in reply #17) on a drawing that shows the wrong RJ-45 pin numbers. My bad.
I will dig out the cable that I made a while back and check if the RJ-45 connector end of this cable is reversed or not.
« Last Edit: June 15, 2015, 10:59:46 am by nixxon »
 

Offline Zucca

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #34 on: June 15, 2015, 08:53:17 am »
This is the flat-cable and adapter, that came with my THS-720P
Pin 9 is not connected at all.

Thanks HighVoltage, you save me to do the same this WE. nixxon I am now curious , does it work now?
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Offline R_G_B_

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #35 on: June 15, 2015, 03:30:09 pm »
Comparing the firmware 1.08 to 1.6 you can see the update speed on the later firmware 1.6 seems faster. Maybe a couple of performance enhancement with regards to waveform update and responsiveness of the UI.

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Offline Zucca

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #36 on: June 15, 2015, 03:46:13 pm »
Comparing the firmware 1.08 to 1.6 you can see the update speed on the later firmware 1.6 seems faster. Maybe a couple of performance enhancement with regards to waveform update and responsiveness of the UI.
R_G_B

I am temped to ship to you my 1.14 and see if you can find any differences... Problem: my THS is now in 2 boxes, after the tear down I never put it back together...
I am finishing my new lab bench and it is taking forever....  :-[
« Last Edit: June 15, 2015, 04:11:59 pm by zucca »
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Offline R_G_B_

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #37 on: June 15, 2015, 04:11:24 pm »
The 720a I have the version 1.08 0f the firmware.  Tektronix dont seem to have mentioned the details  of each firmware revision.
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Offline R_G_B_

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #38 on: June 17, 2015, 02:17:49 pm »
Looking around the net regards to firmware I found this interesting link:
http://jnaudin.free.fr/meg/ths720p.htm

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Offline HighVoltage

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #39 on: June 17, 2015, 02:34:18 pm »
So, it is not True RMS.
What a surprise, I did not know this about the THS720P.



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Offline Zucca

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #40 on: June 17, 2015, 02:38:48 pm »
So, it is not True RMS.
What a surprise, I did not know this about the THS720P.

Same here... thanks R_G_B for the head´s up.
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Offline R_G_B_

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #41 on: June 17, 2015, 06:12:12 pm »
I think they were referring to this project:

http://jnaudin.free.fr/meg/megv21.htm

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Offline nixxon

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #42 on: June 25, 2015, 10:28:34 pm »
...
Thanks HighVoltage, you save me to do the same this WE. nixxon I am now curious , does it work now?

I finally found the cable that I made a while back. I measured the pins, and it is wired according to the TEK FAQ. The cable itself actually seems to work. In PuTTY, when I enter the string "*IDN?", the return string is "TEKTRONIX, THS720A, 0, CF:91.1CT FV:v1.16".

Now I remember that the problem was to get Tektronix Instrument Manager Service to connect to the scope. I get the following error message no matter what I do: "Device proxy (<whatever name I gave the connection">) is running but the attached hardware is not responding. Response string is ()"

info table reads:
Connection: ASRL1::INSTR
Permissions: RWV
SW Status: Starting
HW Status: Connecting

It does not matter if the scope and/or cable is connected or not.

Both the scope and the PC is set to default values:
Baud rate: 9600
Data bits: 8 (on PC)
Stop bits: 1
Flow control: None
Flagging: Hard flagging ON, Soft flagging OFF (on scope)
EOL / Terminator: LF
Delay/Timeout: 0s / None

Any tips on how to make Tektronix Instrument Manager recognise the scope?

EDIT: I am using TekVISA v. 3.3.4 that came with the most recent WaveStar installer. In Windows 7 you have to use TekVISA v. 4.0.0 or later. Now I will uninstall existing TekVISA and install v. 4.
« Last Edit: June 26, 2015, 08:29:24 am by nixxon »
 

Offline HighVoltage

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #43 on: June 26, 2015, 07:49:13 am »
Any tips on how to make Tektronix Instrument Manager recognise the scope?
I had many problems with the Tektronix Instrument Manager and remember calling Tektronix in those days a lot for help.
But it never worked in a reliable way.

At the end of the day I just needed to save the screen shots and for that I used a different software that worked extremely well.
Then I never went back to the Tektronix Instrument Manager.

At one time I got the LabView drives and integrated the scope in to LabView, which also worked perfectly.
That LabView driver even worked in DasyLab.

 
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Offline nixxon

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #44 on: June 26, 2015, 08:54:13 am »
Any tips on how to make Tektronix Instrument Manager recognise the scope?
I had many problems with the Tektronix Instrument Manager and remember calling Tektronix in those days a lot for help.
But it never worked in a reliable way.

At the end of the day I just needed to save the screen shots and for that I used a different software that worked extremely well.
Then I never went back to the Tektronix Instrument Manager.

At one time I got the LabView drives and integrated the scope in to LabView, which also worked perfectly.
That LabView driver even worked in DasyLab.

Thank you for your tips. First I will try installing TekVISA v. 4
 

Offline nixxon

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #45 on: June 26, 2015, 10:42:37 am »
It works now  :D  It was the outdated version of TekVISA on a Windows 7 PC that was the problem.  :palm:  With TekVISA v.4, all is good  :-+
 

Offline nixxon

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #46 on: June 26, 2015, 12:58:55 pm »
...
I found a small piece of software once to make a relative fast screen shot to .JPG from the RS232 port.
It worked very well.
If anyone is interested, let me know and I will upload it somewhere.
...

I am interested in this cute little software. Do you still have it available for upload?
 

Offline Fraser

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #47 on: June 26, 2015, 02:09:33 pm »
I would also be interested in the little software app to capture the screen.

Best Wishes

Aurora
 

Online TheSteve

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #48 on: June 26, 2015, 08:46:02 pm »
This is the original page that has the screen capture program:
www.bobblick.com/techref/projects/ths720/ths720.html

The URL is long gone but you can still see it using the Way Back Machine. I used the tek.exe program for many years with my THS720.

I have attached the Dos/Windows versions, a Linux perl version(remove the .txt) and the original qbasic source code(again remove the .txt). All of it is credited to the original creator Bob Blick.
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Offline HighVoltage

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #49 on: June 26, 2015, 08:51:58 pm »
The screen capture program that I liked so much is not from Bob Blick.
I am traveling right now, will upload it tomorrow with some screen shots.
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Offline nixxon

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #50 on: June 26, 2015, 10:39:12 pm »
This is the original page that has the screen capture program:
www.bobblick.com/techref/projects/ths720/ths720.html

The URL is long gone but you can still see it using the Way Back Machine. I used the tek.exe program for many years with my THS720.

I have attached the Dos/Windows versions, a Linux perl version(remove the .txt) and the original qbasic source code(again remove the .txt). All of it is credited to the original creator Bob Blick.

It seems that the URL is still working bobblick.com/techref/projects/ths720/ths720.html

EDIT 2019-AUG-23: Removed "www" from the above link to make it work.
« Last Edit: August 23, 2019, 08:56:12 am by nixxon »
 

Offline HighVoltage

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #51 on: June 27, 2015, 11:17:43 am »
The screen capture software that I have been using since 1999 is called WinTek32 and was made by Martin Lafferty under the company name of "Production Robots 1997" in England. In those days I was in contact with Martin and he added a few features for me.
The latest Version that he release, is the attached one v2.0.5.21

(I am pretty sure it was freeware at the time, so it should not be a problem, if I am posting the software here.)

I Just hooked it up this morning on my THS720P and it worked flawlessly right away on my old trusted IBM T43P.
Once installed correctly, you just press the hardcopy button on the scope and the transfer starts.
The beauty about the RS232 connection is that it stays connected, even if you disconnect the wire and hook it up to another scope. At times when I had to take a lot of pictures from several scopes, I just had a rotary switch hooked up to different scopes and switched the serial connection between them.

Another good feature about the software was the fact, that you could add a custom text to the screen shot at a position of your choice. With a "#" sign in the target file, you can save numbered sequences of your file.

Here are a few screen shots and the software attached.
Enjoy.
« Last Edit: June 27, 2015, 04:42:36 pm by HighVoltage »
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Offline BravoV

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #52 on: June 27, 2015, 12:47:39 pm »
The screen capture software that I have been using since 1999 is called Wintek32 and was made by Martin Lafferty under the company name of "Production Robots 1997" in England. In those days I was in contact with Martin and he added a few features for me.
The latest Version that he release, is the attached one v2.0.5.21

Complementing HighVoltage's post on WinTek32, attached below in PDF WinTek32 documentation.

Offline Fraser

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #53 on: June 27, 2015, 01:13:13 pm »
Thanks Guys  :-+

Aurora
 

Offline HighVoltage

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #54 on: June 27, 2015, 08:49:41 pm »
There is a nice old "fan page" about the THS scopes that I had forgotten about and just found in my notes.
http://warped.org/tek/

It looks like all the following manuals are still available there:

tektronix-ths710-programming-manual.pdf.zip    070-9245-00    Programming Manual    THS710, THS720
tektronix-ths710-reference.pdf.zip    070-9257-00    Reference Manual    THS710, THS720
tektronix-ths710-service.pdf.zip    070-9246-03    Service Manual    THS710, THS720
tektronix-ths710-user-manual.pdf.zip    070-9247-02    Users Manual    THS710, THS720
tektronix-ths7xxA-programming-manual.pdf.zip    070-9751-01    Programming Manual    THS710A, THS720A, THS730A, THS720P
tektronix-ths7xxA-release-notes.pdf.zip    061-4241-00    Release Notes    THS720A, THS720P, THS730A
tektronix-ths7xxA-reference.pdf.zip    070-9741-01    Reference Manual    THS710A, THS720A, THS730A, THS720P
tektronix-ths7xxA-service.pdf.zip    070-9752-01    Service Manual    THS710A, THS720A, THS730A, THS720P
tektronix-ths720A-service-2.pdf.zip    070-9750-02    Service Manual Supplement    THS720A MOD NV
tektronix-ths7xxA-user-manual.pdf.zip    070-9731-05    User Manual    THS710A, THS720A, THS730A, THS720P
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Offline posplayr

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #55 on: January 12, 2016, 02:57:17 am »
Hi gang,
   I was reintroduced to this site while looking for ways to upgrade my THS730A. This thread in particular was very interesting especially the battery replacement options. After considering what was posted (maybe someone else already has done this) I decided rather than replace the expensive battery pack with another aftermarket Ni-Cd pack and also rather than go AA Ni-MH I found some relatively inexpensive C size Ni-MH (500 mAhr as compared to the 2800 OEM pack).

You can such on Amazon for Clear PCV shrink tubing:
2M 43mm 27mm Dia PVC Heat Shrink Tubing Clear for 1 x 26650 Battery ($6.06 with Amazon Prime FREE shipping)

I also thought these would be worth a shot; My scope sits on the bench a lot and so I don't really need to take it into the field and expect 10 hours everyday. Beside, I have enough PVC shrink tubing to redo the battery pack several times.
EBL 5000mAh High Capacity Ni-MH Rechargeable C  ($17.99 with Amazon Prime FREE shipping).

I just cut the PVC cover off of my old battery pack (Circa 1995), prised the metal tab off the positive post that had been welded. Reassembled in sections starting with the two inner batteries. After a little trial and error, it is best to shrink in the ends before trying to shrink the center. It pulls the two 1/2 together.

The starting point:



Assembled two middle batteries, being sure to extend past the ends to pull them together.



Finished product; there are 4 layers of PVC is most areas.



Quick look running without the charger. The batteries came with just over 4.6V with the series pack. After inserting the pack into the scope, the LOW BATTERY indication quickly came on. I charged them for a while and went back to show that the indicator stayed off (i.e. the internal charger is working). Basically this cost me $24. Even if the batteries do not work out, I can upgrade for a modest cost. The process seems to work and there is no need to solder or weld if you have an original battery. If not then a thin brass sheet would work well to replace the stainless .



No need for welding, the stainless strap is held in place with the PVC wrap.
« Last Edit: January 12, 2016, 04:19:59 pm by posplayr »
 

Offline HighVoltage

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #56 on: January 12, 2016, 09:21:31 am »
How did you re-connect the metal straps to the new batteries?
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Offline posplayr

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #57 on: January 12, 2016, 04:28:37 pm »
The original post has an added picture (at the end) showing the strap.

I opened up the inner PVC cover of the OEM battery after completing this and saw that each battery has a tab welded between it's neighbor. Seemed overkill and perhaps why the pack costs so much. The flexible metal of the tabs is not stainless so it invites more corrosion between batteries but given the welds that doesn't matter much.

I do not see the need to weld the tabs to the battery ends except in the most caustic environments which my scope never sees and I doubt most never will either. The PVC does quiet well holding the pack in alignment and the battery lives in a battery compartment under axial pressure so there is plenty of contact pressure to flow the 1 odd amp that is required.

The resting voltage was 5.6V after charging overnight. If I get bored I might do a run down test but that is a big "if". Regardless, of the result, the methods appears to hold C size batteries together without welding. If you do not have the strap and use brass you only need to solder the length wise strap to the band. The PVC wrap will hold the rest in place.
« Last Edit: January 12, 2016, 05:05:06 pm by posplayr »
 

Offline Fraser

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #58 on: January 12, 2016, 04:33:45 pm »
Nice job !

I have the batteries, metal strips and tab welder to do the same. I must get around to that this year. I am fortunate to still have spare working batteries, but they are getting quire old now so new ones would be a good idea.

Thanks for sharing your rebuild.

Fraser
 

Offline HighVoltage

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #59 on: January 12, 2016, 04:44:45 pm »
This is indeed a really nice way to prepare the batteries for the scope
At the moment I still have one good battery working with an original charger.
But the time will come to upgrade the scopes.
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Offline posplayr

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #60 on: January 12, 2016, 05:34:32 pm »
Thanks guys  :D

Although I don't feel it is nessesary from to weld taps for this application from either an electrical or structural perspective here is a video of a home made spot welder.



I did not realize these were so cheap. I guess if you are going to setup production then it might be a good thing to have.

AC220V 18650 Battery Point Welder Machine Welding Machine Mini Notebook Mobile

http://www.ebay.com/itm/AC220V-18650-Battery-Point-Welder-Machine-Welding-Machine-Mini-Notebook-Mobile/391322379449?_trksid=p2047675.c100009.m1982&_trkparms=aid%3D777000%26algo%3DABA.MBE%26ao%3D1%26asc%3D35006%26meid%3D867f670f564b4fa48c4070d375c7064a%26pid%3D100009%26rk%3D1%26rkt%3D1%26sd%3D311446206476
« Last Edit: January 12, 2016, 05:40:32 pm by posplayr »
 

Offline Fraser

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #61 on: January 12, 2016, 06:11:35 pm »
That is the model of tab welder I bought. It works really well and you only need to file the hard drawn copper electrodes to keep it producing excellent welds. Electrodes are just hard drawn copper wire and so easy to replace.

IIRC I run my unit on setting 20 to 25 but the unit goes all the way to setting 40. I find my house circuit breaker pops at anything above 35 though.

I reviewed the contents of the unit in a thread on this forum. Pictures included. It is a transformer based tab welder with TRIAC control.

IIRC my tab welder cost me around GBP80 delivered to the UK. I wouldn't be without it now. I use it to add tabs to many memory backup Lithium button cells and for rebuilding expensive battery packs for my thermal cameras. The unit paid for itself after rebuilding one FLIR PM series pack that costs over GBP200 + VAT new. I have around 20 such battery packs !

Fraser
 

Offline posplayr

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #62 on: January 12, 2016, 06:55:34 pm »
Thanks for the added info; glad I stumbled back in here  :)

Given my prior ebay shopping patterns, I might have bought a cheap Chinese USB scope and taken a big step backward from my THS730A!

BTW, I contacted Tektronix about a replacement zero adjust knob for my A622 Current Clamp. Apparently there is one coming in the mail for free. First time I asked for anything after buying the scope 20 years ago.

I need to find a A622 break down thread that deals with high battery current consumption. Mine started to pull the 9V battery down real fast, but still runs off a power supply hooked to the 9V contacts.

« Last Edit: January 12, 2016, 07:01:22 pm by posplayr »
 

Offline Fraser

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #63 on: January 12, 2016, 08:18:28 pm »
I have used a thermal imaging camera to view a PCB that was eating batteries. It was quickly clear that one chip was running hot. It turned out to be the cause of the fault. Do you know anyone who can use a thermal camera on your probes PCB?

The alternative is to systematically isolate the active parts of the PCB in an effort to see which component is drawing the lions share of the operating current. Tantalum capacitors can fail and load supply rails. In such a case, a thermal camera would reveal the effect rather than the cause, as other components on the supply line to the capacitor may warm up.

Fraser
 

Offline posplayr

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #64 on: January 12, 2016, 09:37:43 pm »
Good idea on the thermal imager. I was aware that caps can go out but not really any idea on how to isolate other than change them all out. I don't have a thermal imager, but do have a HF handheld unit that I might be able to scan on the board to detect a temp rise.
http://www.harborfreight.com/non-contact-infrared-thermometer-with-laser-targeting-60725.html

BTW, the complementary zero adjust knob from Tektronix just arrived in the mail today  :)
« Last Edit: January 12, 2016, 09:39:15 pm by posplayr »
 

Offline hibone

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #65 on: January 13, 2016, 02:32:37 am »

Hi there, when replacing the original battery, what do you use?

IIR each C-sized battery can be replaced with 4 AAA sized ones.

If thats the case, and taking into account that the internal charger is a trickle one (if I'm not mistaken), do you think it would be possible to replace the whole batteries with 16 AAA eneloop batterys (or similar hybrid nimh) and charge them within the scope?
 

Offline BravoV

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #66 on: January 13, 2016, 02:49:36 am »
Had anyone ever measure the trickle charge current ?

The original cells are nicd, which is more forgiving than nimh cell, and one of the reason I use the detachable method so I can charge externally each at proper nimh charger.

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #67 on: January 13, 2016, 06:19:46 am »
Good question, I guess I side the stepped of battery charging issue. The packaging works regardless of using Ni-CD or Ni-HM.
 don't know what precautions you take with AA Ni-MH batteries in your THD7xx but it sounds like you never run the device with the DC charge input connected?  Whatever charge rates an AA Ni-MH would have the C size is going to be about 1/2 the charge rate. (2500 Amp-Hr v.s. 5000 Amp-hr)

In the first post Zucca stated:

Quote
The battery charger works like this (according to my reverse engineering):

VBatt <3.5V: CC charge at 110mA
VBatt >3.8V: charge current [mA]= -187.27*VBatt[V]+1283.63
3.5V<VBatt <3.8V: Previous state

according to the formula the max charging current at 3.8V is .57 amps or 0.2C for a 2800 mAmp-Hr or 0.11C for a 5000 mAmp-Hr.

According to:

http://batteryuniversity.com/learn/article/charging_nickel_metal_hydride

Quote
On September 9, 2011 at 9:11pm
Edward wrote:
the best C-rate for chargeing NiMH is 0.2C-rate charge 6Hours

So the optimum charging rate for the Ni-CD and the Ni-MH is the same, but the apparently the Full charge detection is much more difficult and trickle charging is different.

However, this statement suggest that putting in a 5000 Ni-MH v.s. 2800 NiCd Amp-Hr battery is OK as we can probably assume that Tektronix put a quality charger into the scope and it trickle charges at C/10 as (the recommended optimum) That would put the 5000 NiMH at 2800/5000*.1=0.056C very close to the recommendation for trickle charging a NiMH.

Quote
NiMH dislikes overcharge and the trickle charge is set to around 0.05C. NiCd is better at absorbing overcharge and the original NiCd chargers had a trickle charge of 0.1C. The differences in trickle charge current and the need for more sensitive full-charge detection render the original NiCd charger unsuitable for NiMH batteries. A NiMH in a NiCd charger would overheat, but a NiCd in a NiMH charger functions well. Modern chargers accommodate both battery systems.

I left the NiMH in the THS730A overnight last night charging and the pack was only luke warm this morning. This is apparently OK.
There is this warning, so it is probably best to unplug the charger from the Scope when left off for extended periods. The built in NiCd charger is probably going to be worse on a AA battery than the higher capacity C size as the AA will be charging at close to twice the C rate.

The bottom line is that while I'm not going to get optimum performance out of the batteries using the built in NiCD charger, it is still going to charge the NiMH C pack within nominal recommendations and will probably only cause an issue if left for weeks on the charger without using the scope. That is easily avoided by unplugging the DC charger input to the scope.

I just checked in my Hardcase case and I see I have an extra battery pack (dated 1998 the first was 1995) and I also have the TEK-Scope battery charger. I guess I could open it up and convert it to a fast charge NiCD charger (another project?)   

To a certain extent, using the AA batteries because you can charge them in a real external NiMH charger causes a problem with excessive trickle charge rates if those same batteries are left in the scope. On the other hand if you put  Type C NiMH batteries with higher capacity, the charge rates are slower (as would be expected) but closer to acceptable trickle charging rate of the Ni-MH battery technology.

There is certainly nothing prohibiting converting the the external charger to NiMH and then if you are working a lot on battery power with the scope, you can much more quickly recharge the pack off grid.

I have a Tenergy TB6B Intelligent charger that I could probably adapt to do a 4 cell NiMH effectively and just not bother to modify the internal charger. http://www.tenergy.com/01321

Comments welcome, but with a small amount of care, there should be no issues leaving the battery pack in the scope overnight, just not indefinitely.
« Last Edit: January 13, 2016, 06:59:54 am by posplayr »
 

Offline BravoV

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #68 on: January 13, 2016, 07:27:52 am »
As I posted at 2nd post in this thread, I use the AA -> C adapter and built the batt pack, ghetto mod and not pretty though, with lots of hot glue and shrink tubing, but it works flawlessly.

As the adapter designed, I can open the pack to replace the AA cells without having to lug many of the long, huge C sized 4 cells tubes as spare when working at the field.

Good LSD AA cells like Eneloop brand are enough to provide similar capacity as the original C sized NiCd cells, and also its convenient to carry many of them pre-charged inside the scope's bag.

Too bad I don't have my batt tube with me now, will post the photo of it once I had the chance.
To give you a clue, these picture below are the AA -> C adapters that I used to build the batt tube, it has latch sideway to access the AA cells inside for replacement of the depleted cells.


Offline posplayr

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #69 on: January 13, 2016, 08:49:07 am »
I pulled the Quad "C" pack out of the scope and put into the external Tek-Scope "Fast NiCAD Battery charger". The pack was already pretty well charged (from the night before) as despite leaving the scope on it goes to sleep and I have not rigged a good resistive load yet to bleed it down.

I used the HF infrared thermometer   to monitor the temperature. The red LED on the charger started and the battery pack warmed up to luke warm. With teh charger being about 80 degF (the drywall behind at 72 degF) the battery rose to about 94 degF at center and closer to high 80's at the ends. The feel was consistent with what I discovered this morning when pulling the battery out of the scope after charging all night.

After about another 1/2 hour the battery mid section which gets hotest was at about 104 degF. It was not so hot that you could not hold it firmly. About luke warm. After a while longer the green charger light came on and I pulled the battery pack. By this time the charger was in float and the temperature dropped back to about 97 degF.

I pulled the pack and reinserted it into the charger and the LED went back red as if to restart a new charge cycle. I opened up the charger and there is a little PIC processor in there.

I just ordered another set of same batteries for $17.99 shipped so I'll have a backup as well. Plenty of PVC shrink wrap left.
 

Offline hibone

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #70 on: January 17, 2016, 10:36:19 pm »
I think 4 of these battery holders would do. Now the only problem is to find a nickel/brass/copper strip or whatever.

16 Eneloop batteries will cost almost half the price of the original battery but I guess they will last a heck of time, and can be recharged within the scope.
 

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #71 on: January 18, 2016, 06:22:25 am »
I think you will be hard pressed to pay less than the 4 NI-MH C cells @ 5000 mA-Hr,($18) not requiring holders and they are far less likely to overcharge in the scope. On top of that they have more capacity. Am I missing something????
 

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #72 on: January 18, 2016, 06:30:43 am »
Eneloops have a very low self discharge so the meter can sit a long time and still be powered by previously charged batteries. At the cost difference though I think I'd lean more towards the 4 cheap C cells or just use 4 2500mAh AA cells as they still offer good run time and are pretty cheap.
VE7FM
 

Offline hibone

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #73 on: January 18, 2016, 09:09:08 am »
I think you will be hard pressed to pay less than the 4 NI-MH C cells @ 5000 mA-Hr,($18) not requiring holders and they are far less likely to overcharge in the scope. On top of that they have more capacity. Am I missing something????

There is what TheSteve says about eneloops.
Also, if  I am not mistaken, eneloops should operate much longer before they wear out (10 years or so), with respect to standard ni-mh.

I am thinking of 4 AAA batteries, in place of one C-sized cells, because as far as i remember,  each C-side cell is made out of 4 AAA sized batteries all the same. Also eneloops seem to have a much more consistent voltage, with respect to other batteries, thus they are less prone to equalization problems when charged in parallel. Thus they can be charged within the scope, without disassembly the battery.

Of course there's the problem with the charge current, as well. That is the reason why I feel that replacing a C cell with one AA it won't do well.

Indeed the price it is high, maybe I should look for some cheaper replacement with respect to eneloops. In the end Sanyo is not the only one that makes hybrid nimh cells.

Well of course, all of this may be not worth the while.
 

Offline R_G_B_

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #74 on: January 18, 2016, 01:27:09 pm »
Hello,


I  had a go at using four AA eneloop batteries using a C cell adaptor. The problem is there's no room to close the cap on the top of the THS720 DSO.

Maybe its the type of C cell adapters I am using:

http://www.ebay.co.uk/itm/Newest-Panasonic-eneloop-C-Size-Spacer-4-Pack-Battery-AA-Cell-Adapter-Converter-/221993148950?hash=item33afd2a216:g:KaQAAOSwI-BWHRPY

Thanks

 R_G_B
 
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Offline posplayr

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #75 on: January 18, 2016, 10:35:19 pm »
I would be wary of running AA batteries with the scope's NiCD charger as they are generally only about 2200 mA-hr v.s the C cell which is 5000 mA-hr. The C cell got a little more than lukewarm at 105 deg in a 72 degree room as per my tests) when charging in an open case Charger designed for a NiCD battery at .2C charge rate.

If you stick a 2200mA-hr AA battery (in a C adapter) in it's stead in the enclosed case of the Scope I don't know what temperature the battery will get to but it would certainly be a concern and possible thermal runaway???. Remember this a NiCD charger named "fast charge" operating on a Ni-MH. Not a good thing.

As I described before the 5000 mA-hr C cell effectively drops the "C" charge rate in 1/2 providing a substantial margin to avoid stressing and heating of the battery due the design spec of the NiCD charger for the 2800 mAmp hr NiCD C cells.
 

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #76 on: January 18, 2016, 11:17:08 pm »
We've had no issues with excess heat using 2500 mAh Eneloops cells. We only use the scopes built in charger and not the external fast charger. The factory battery was rated at 2800 mAh and was probably closer to 2000 after a few uses anyway, so I see no issue with the internal trickle charger.
VE7FM
 

Offline R_G_B_

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #77 on: January 18, 2016, 11:21:39 pm »
I was trying to use AA 2500mah.

R_G_B
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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #78 on: January 18, 2016, 11:39:01 pm »
I was trying to use AA 2500mah.

R_G_B

The battery door on our THS730A will just close - but it is a tight squeeze!
VE7FM
 

Offline posplayr

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #79 on: January 19, 2016, 12:48:13 am »
We've had no issues with excess heat using 2500 mAh Eneloops cells. We only use the scopes built in charger and not the external fast charger. The factory battery was rated at 2800 mAh and was probably closer to 2000 after a few uses anyway, so I see no issue with the internal trickle charger.

OK Well that is good to know. I know some people were rationalizing the AA so they could be charged separately on a proper Ni-MH charger. I also did not know that the external charger had a faster charge rate than the internal? I would have thought the trickle phase would have been the same for either and so it would be twice as much as you would want for the NiMH without the increased capacity.

I bought a second set of C cells so for $40 I have two battery NiMH packs of 5000 mA-hr rating.
 

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #80 on: January 19, 2016, 12:58:57 am »
Unless I somehow totally missed it the internal charger on the THS7xx series is trickle only. The external charger is a fast type charger which should use a negative delta V (peak detect) which is unsuitable and shouldn't be used for NiMH cells(they have a much smaller drop when charged).

Unless of course the charger is horribly designed and uses a timer, I haven't opened the one here.
VE7FM
 

Offline posplayr

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #81 on: January 19, 2016, 02:06:25 am »
Unless I somehow totally missed it the internal charger on the THS7xx series is trickle only. The external charger is a fast type charger which should use a negative delta V (peak detect) which is unsuitable and shouldn't be used for NiMH cells(they have a much smaller drop when charged).

Unless of course the charger is horribly designed and uses a timer, I haven't opened the one here.

I don't know; the OP claimed to have "reverse engineer the battery charger" I assumed they meant the one inside of the scope. Using his numbers it would be charging at C/5.

Quote
The battery charger works like this (according to my reverse engineering):

VBatt <3.5V: CC charge at 110mA
VBatt >3.8V: charge current [mA]= -187.27*VBatt[V]+1283.63
3.5V<VBatt <3.8V: Previous state

To which I added in a prior post.

Quote
according to the formula the max charging current at 3.8V is .57 amps or 0.2C for a 2800 mAmp-Hr or 0.11C for a 5000 mAmp-Hr.
« Last Edit: January 19, 2016, 02:08:18 am by posplayr »
 

Offline HighVoltage

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #82 on: January 19, 2016, 09:24:30 am »
I just opened my original Tektronix external charger and took some pictures.
Here you go:
 
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Offline posplayr

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #83 on: January 20, 2016, 12:38:05 am »
I just opened my original Tektronix external charger and took some pictures.
Here you go:

Looks like the one I charged the NiMH "C" cell stack with as reported above.
The little PIC controller tells me it must be "smart"  :phew:
 

Offline R_G_B_

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #84 on: January 23, 2016, 08:54:16 pm »
Heres very simple mod to allow the use of eneloop 2500mah batteries:

AA to C converters two of them cut down.

Paper clip

Tape

multi strand Wire

The multi strand wire will push its-self against the cap no problems with this at all even if you give the scope a firm shake everything is a tight fit and stays in place.

R_G_B

 
« Last Edit: January 23, 2016, 08:57:00 pm by R_G_B_ »
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Offline Zucca

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #85 on: February 17, 2016, 08:38:31 am »
I don't know; the OP claimed to have "reverse engineer the battery charger" I assumed they meant the one inside of the scope. Using his numbers it would be charging at C/5.

Right! I had the 12V DC External plugged in and a DC Load (BK Precision 8500) instead the battery. I was simply going up and down with the V on the DC Load and tracking down the current the internal scope charger was spitting out.

Those 5000mAh C size look sexy!

Anyway my dream is to mod the battery door into a little PCB:

- get rid of that funky OEM battery + terminal
- support for Li-Ion Cells (according to my investigation 3 cells could fit just right...)
- Leds on the outside for the State of charge
- Switch(light sensor  >:D) for the display back light (why has to go always on? that´s such a waste...)

and yes probably it would be not water splash proof anymore... I can survive with it.

I started to dig into the schematics to understad if I can mod the internal charger circuit so I have to do less circuit on the battery door.
In the not P models there is also plenty of room for another PCB above the scope middle, but holy cow I'm scared for EMI...

It´s not easy.
« Last Edit: February 17, 2016, 08:41:47 am by zucca »
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Offline posplayr

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #86 on: March 09, 2016, 05:57:30 am »
I don't know; the OP claimed to have "reverse engineer the battery charger" I assumed they meant the one inside of the scope. Using his numbers it would be charging at C/5.

Right! I had the 12V DC External plugged in and a DC Load (BK Precision 8500) instead the battery. I was simply going up and down with the V on the DC Load and tracking down the current the internal scope charger was spitting out.

Those 5000mAh C size look sexy!


Thanks for the confirmation on the charge rate. I have not burned my lab down yet so the 5000 mA-hr must be good right? :phew:
 

Offline Zucca

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #87 on: March 09, 2016, 07:19:47 am »
Thanks for the confirmation on the charge rate. I have not burned my lab down yet so the 5000 mA-hr must be good right? :phew:

I think so, don´t see any down side on the 5000 mAh/hr. Yea the eneloop hold the charge for very long period of time, but I think I will always charging up the scope the day before going in the field. In cases of emergencies they are not eneloop but they are not the opposite neither, so I think they will still be reasonabily charged up also after a year or so.
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Offline hibone

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #88 on: April 18, 2016, 04:51:16 pm »
Dear all,

In my device, the "gentleman" who assembled the scope, left the flat flex cable of the LCD in the battery holder. As a result, the cable broke just when I needed the scope.

I suppose a replacement can be found pretty easily, but I am no expert, thus I wonder what aspects I should look for.
To me the cable appear as a 12 way 1mm pitch flat flex ribbon 9 cm long.
The pitch and the number of ways cannot change, of course, but I dunno if thickness and the length have to be the same as well.

In a printer I found a flat flex cable, 5cm long, with 50 ways or so. This cable is also a little more thick than the original. I cut out the 12 ways I needed, and put the cable in place.

Well, the screen lit on, but it remained blue without showing anything.
Now I wonder about the reason.
I dunno if the problem is due to:
- the pins that may be oxidized.
- the fact that the cable is not an original 12-way cable and the pins end out of place?
- the thickness, that may cause the cable not to touch correctly on the pins

Also, if I put on the original broken cable, and pinch it over the cut with my fingers, so that the broken ends of the cable touch, something is shown on the LCD.

Sorry for the much details. Please if you have any suggestion tell me.

PS.
Out of curiosity I "naively" asked Tektronix the spare part.
- "We are sorry but the part you request is out of production. However you can send your device for repair to our service center in Cologne." (I live in Italy)
- "How much would it cost?"
- 1k € plus shipping
 
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Offline HighVoltage

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #89 on: April 18, 2016, 05:53:05 pm »
PS.
Out of curiosity I "naively" asked Tektronix the spare part.
- "We are sorry but the part you request is out of production. However you can send your device for repair to our service center in Cologne." (I live in Italy)
- "How much would it cost?"
- 1k € plus shipping
I have even heard, that when you send it to Cologne, it will be forwarded to the US for repair.

Anyhow, can you repair the cable?
Just get the insulation removed and fine solder it together?
May be you have a picture?
 
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Offline hibone

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #90 on: April 18, 2016, 07:33:19 pm »
Actually, I cleaned the replacement cable with isopropyl alcohol and then everything worked just fine.

I tried to remove the insulation with fine sandpaper but it seemed quite hard not damaging the rest of it.

Honestly  I didn't feel all that comfortable about a repaired cable there. Thus I abandoned the idea.
The original cable is about 9 cm and should be folded under the lcd monitor, which has a metal shield.

A soldered joint there may have safety and reliability issues.

Hope my previous post can be of use to the forum.
Thanks anyway.


 
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Offline jcd06

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #91 on: November 15, 2016, 02:00:50 pm »
Hi folks,
I've bought a secondhand THS720 lately and I found this exelent discussion while I was looking for some documentation.
I would like to be able to send screenshots to the PC and I could see here the different RG-45-to-DB9 cable pinouts discussed.
Unfortunately it's a bit unclear for me which of the pinouts is the definitive/right one.
Can someone point it out for me please?
Thanks,
Jean
 

Offline HighVoltage

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #92 on: November 15, 2016, 03:26:32 pm »
Here you go for the original connector:
I made my own wire, because the original cable is sooo stiff.

RJ45   Wire Color   Function   9 pin (female)
1   (Brown)   DCD- Data Carrier Detect   7 - RTS
2   (Blue)      DSR- Data Set Ready   4 - DTR
3   (Yellow)   DTR - Data Terminal Ready    6 - DSR
4   (Green)   GND - Signal Ground   5 - GND
5   (Red)     RXD - Receive Data    3 - TXD
6   (Black)    TXD - Transmit Data   2 - RXD
7   (Orange)   CTS - Clear To Send   7 - RTS
8   (Gray)    RTS - Request To Send   1&8 - DCD/CTS

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Offline TurboTom

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #93 on: November 18, 2016, 11:53:25 pm »
Hacking the THS 700 series works perfectly well!  :D ...just converted a THS710A to a THS720P  :D

At 100MHz I measured a level drop of about 0.9dB. Didn't bother to measure the 3dB frequency. Also power measurements work (firmware 1.14 on mine).

If you have a 710A, just remove resistors R207, R213 and R205 (to make it a 720P) or R204 (to make it a 720A). Hacking it into a THS730A isn't easily possible since other front-end hybrids would be required among some other stuff.

Cheers,
Thomas
 
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Offline R_G_B_

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #94 on: November 19, 2016, 12:08:19 am »
Be interesting to see what each firmware does... I have a 720A firmware 1.03 I think it is. Also is there anyway to grab the latest firmware and has anyone attempted it yet?
« Last Edit: November 19, 2016, 12:10:04 am by R_G_B_ »
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Offline BravoV

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #95 on: November 19, 2016, 05:49:05 am »
Hacking the THS 700 series works perfectly well!  :D ...just converted a THS710A to a THS720P  :D

At 100MHz I measured a level drop of about 0.9dB. Didn't bother to measure the 3dB frequency. Also power measurements work (firmware 1.14 on mine).

If you have a 710A, just remove resistors R207, R213 and R205 (to make it a 720P) or R204 (to make it a 720A). Hacking it into a THS730A isn't easily possible since other front-end hybrids would be required among some other stuff.

Cheers,
Thomas

Wow , thank you Thomas !  :-+

Mind share how you figure that out ? By comparing ?

I have 710A with 1.11 firmware, as R_G_B above, anyone know how to upgrade it ?
« Last Edit: November 19, 2016, 05:53:01 am by BravoV »
 

Offline Zucca

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #96 on: November 19, 2016, 06:49:00 am »
Also is there anyway to grab the latest firmware and has anyone attempted it yet?

give me 2 more days
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Offline R_G_B_

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #97 on: November 19, 2016, 10:16:07 am »
Hacking the THS 700 series works perfectly well!  :D ...just converted a THS710A to a THS720P  :D

At 100MHz I measured a level drop of about 0.9dB. Didn't bother to measure the 3dB frequency. Also power measurements work (firmware 1.14 on mine).

If you have a 710A, just remove resistors R207, R213 and R205 (to make it a 720P) or R204 (to make it a 720A). Hacking it into a THS730A isn't easily possible since other front-end hybrids would be required among some other stuff.

Cheers,
Thomas

Crazy the amount of money you can make on  just a couple of resistors!


Now Watch the eBay sale price on these go through the roof.


I remember the fluke 120 series you could buy a used one on eBay around 100 pounds. Forget that now they go for up to £600 for a 123 and around a £1000 now for a fluke 124 or 125. Insane!
« Last Edit: November 19, 2016, 10:24:56 am by R_G_B_ »
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Offline HighVoltage

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Re: Tektronix THS720A Portable Scope Hack/Teardown/Discussion
« Reply #98 on: November 19, 2016, 10:46:34 am »
TurboTom
That hack is great.
I have a few "none P" versions and will try it out.
Thanks so much
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Offline BravoV

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Re: Tektronix THS720A Portable Scope Hack/Teardown/Discussion
« Reply #99 on: November 19, 2016, 11:01:54 am »
TurboTom
That hack is great.
I have a few "none P" versions and will try it out.
Thanks so much

HighVoltage, please, if its not too troublesome, do photos documentation and share it here, preferably before and after the mod.

I believe this mod will attract many of this Tek THS7x0x owners.  :-+

 :popcorn:

Offline BravoV

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Re: Tektronix THS720A Portable Scope Hack/Teardown/Discussion
« Reply #100 on: November 19, 2016, 11:17:55 am »
Damn, I'm so excited, here the resistors locations, photo courtesy of Zucca's teardown.



 
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Offline R_G_B_

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Re: Tektronix THS720A Portable Scope Hack/Teardown/Discussion
« Reply #101 on: November 19, 2016, 03:34:34 pm »
Please could you post the screen capture of a 710A or 720A  showing as a 720P in power analyser mode.

Thanks 
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Offline R_G_B_

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Re: Tektronix THS720A Portable Scope Hack/Teardown/Discussion
« Reply #102 on: November 19, 2016, 03:36:11 pm »
Also how easy would it be to get the firmware off of one of these things ?
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Offline Zucca

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Re: Tektronix THS720A Portable Scope Hack/Teardown/Discussion
« Reply #103 on: November 19, 2016, 05:20:43 pm »
Also how easy would it be to get the firmware off of one of these things ?

In my eyes very easy. J1 is the magical connector  (Molex 15-92-2480, to be confirmed)

which give access to the

Quote
U1

IC, MEMORY; CMOS, FLASH ;1MEG X 8, 5.0
VOLT--ONLY, SECTOR ERASE;
AM29F080--120EC , 40PIN TSOPT&R

which has the FW in it. A TL866 should do the job, I think to keep the µC in Halt State by connecting pin 78 to 79 on J1 so it will not interfere when reading out the EEPROM.

Only thing I need is the freaking AMP 2x40pin 1,27mm pitch plug...

Maybe this one?
http://www.ebay.com/itm/2-AMP-80-Pin-Male-D-Sub-Connectors-from-Intel-2xx-Backplane-/160351413820

Anyone can tell me what AMP plug I need to buy?

This one? I think I got it.
http://www.ebay.de/itm/SCSI-Adapter-intern-68-Pin-auf-80-Pin-SCA-/291942990210?hash=item43f9288182:g:2msAAOSwiDFYKjQW
 
« Last Edit: November 21, 2016, 05:50:57 pm by zucca »
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Offline Zucca

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Offline BravoV

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #105 on: November 19, 2016, 08:01:43 pm »
Zucca, so are you saying, once the CPU's HALT pin is enabled externally through pin 78, while tapping the data bus (D0-D7) and the address bus (A0-A19) through the SCA connector, say connected to TL866 thru "creative" wiring at that SCA, we can read or write the flash AM29F080 ? CMIIW

Btw, just checked, TL866 supports AM29F080 officially.

Excerpt from MC68331 user manual :
Quote
4.4.1.10 Halt Signal
The halt signal (HALT) can be asserted by an external device for debugging purposes
to cause single bus cycle operation or (in combination with BERR) a retry of a bus cy-
cle in error. The HALT signal affects external bus cycles only, so a program not requir-
ing the use of external bus may continue executing, unaffected by the HALT signal.
When the MCU completes a bus cycle with the HALT signal asserted, DATA[15:0] is
placed in the high-impedance state, and bus control signals are driven inactive; the ad-
dress, function code, size, and read/write signals remain in the same state.
If HALT is
still asserted once bus mastership is returned to the MCU, the address, function code,
size, and read/write signals are again driven to their previous states. The MCU does
not service interrupt requests while it is halted. Refer to 4.5.5 Bus Exception Control
Cycles for further information.

Offline TurboTom

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #106 on: November 19, 2016, 08:14:24 pm »
Here some photos -- haven't yet assembled a serial cable to download the screenshots directly. Sorry for the poor quality, had to use the shitty cell phone camera  ::)

Cheers,
Thomas



P.S. Sorry, forgot to set date and time correctly...   ;)
« Last Edit: November 19, 2016, 08:17:54 pm by TurboTom »
 

Offline HighVoltage

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #107 on: November 19, 2016, 08:17:00 pm »
That is impressive.

The THS720P is the one that always sells for the highest price on ebay.
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Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #108 on: November 19, 2016, 08:17:33 pm »
Oh yeah BravoV... that is my plan...
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Offline BravoV

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #109 on: November 19, 2016, 08:24:59 pm »
Here some photos -- haven't yet assembled a serial cable to download the screenshots directly. Sorry for the poor quality, had to use the shitty cell phone camera  ::)

Thomas, thank you so much, now I'm convinced. Definitely will mod my 710A, just by doing few resistors, free upgrade from 60Mhz to 100Mhz and extra harmonic analysis and power measurements features enabled.  :-+

Your firmware is 1.14 , wonder if my firmware 1.11 is enough for this mod ?

Btw, the latest is 1.16 isn't it from what I gathered from internet.

Offline R_G_B_

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #110 on: November 19, 2016, 10:58:47 pm »
Looks like the firmware changes were about fixing bugs in the firmware ..

https://forum.tek.com/viewtopic.php

R_G_B
 

Offline TurboTom

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #111 on: November 20, 2016, 11:33:55 am »
When I received my (then) THS710A, both scope channels showed some DC offset that changed with the input sensitivity ranges selected. DC path compensation didn't correct this and I read somewhere in the forum that this is relateds to "worn out" analog optocouplers (CNR-201A) that are used to transfer the DC component of the input signal across the isolation barrier. Since these components are not particularly expensive. I decided to get some and replace them.

Guess what the result was: Same picture as before  :o

As a last resort I thought the complete factory calibration of the scope section might possibly help, and fortunately, it did the trick!  DC offset vanished completely. ;D

I just wanted to post the information in this thread since it seems to be the most comprehensive and as I understand, many of the THS700 models suffer more or less severely from the DC offset over the time. Calibration is very simple and all that's required for the job is a good (arbitrary) function generator that's capable of outputting a square wave with half-way decent rise time (<20ns) and a DC voltage (the accuracy of the latter should be checked with a reliable multimeter).  Fortunately, the scope section and the DMM section of the THS700 is calibrated separately and the DMM section calibration is very unlike to deteriorate over time.

All the information required for the job is available in the service manual, starting at page 51: http://de.tek.com/oscilloscope/ths720a-manual/ths710a-ths720a-ths730a-ths720p-service-manual

My recommendation in case of DC offset problems is to try this calibration before swapping out any components, especially since removal of the analog isolators is a real PITA....

Cheers,
Thomas


P.S. Some calibration steps really take some time and the instrument may appear like it's crashed -- just get yourself a cup of coffee (or whatever you feel like having at the time...) and wait. The screen contrast is set to 50% during calibration, on my THS700 this results in a rather dim screen (normally it's set at 65%), so don't worry if something like this happens.
« Last Edit: November 20, 2016, 07:25:34 pm by TurboTom »
 
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Offline BravoV

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #112 on: November 20, 2016, 12:40:42 pm »
Looks like the firmware changes were about fixing bugs in the firmware ..

https://forum.tek.com/viewtopic.php

I searched, but can't find it ?  :-//

Anyway, if its bugs fixed, then I'm looking for 1.16 dump, anyone ?

Offline R_G_B_

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #113 on: November 20, 2016, 03:10:52 pm »
Looks like the firmware changes were about fixing bugs in the firmware ..

https://forum.tek.com/viewtopic.php

I searched, but can't find it ?  :-//

Anyway, if its bugs fixed, then I'm looking for 1.16 dump, anyone ?

Try this
https://forum.tek.com/viewtopic.php?t=138280
R_G_B
 

Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #114 on: November 20, 2016, 10:24:46 pm »
As a last resort I thought the complete factory calibration of the scope section might possibly help, and fortunately, it did the trick!  DC offset vanished completely. ;D

Thanks for confirming again this:
https://www.eevblog.com/forum/repair/tek-ths720a-thinks-there-are-110v-on-the-input-but-there-is-just-a-50-ohm-r/msg870999/#msg870999

Mine has the same issue, but I want first to dump out the U1 AM29F080, then calibrate it. After I will compare the two U1 contents to understand where the calibration variables are. There will be surely a CRC, so not so easy... willl see.

 
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Offline 1audio

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #115 on: November 21, 2016, 05:37:47 am »
I have a really early THS720 (non-a) and 1) the 720P hack doesn't work. Moving the jumper turns it into a THS770??. No idea what that is and I saw no features of interest.

The PCB is different around the meter inputs and would not support later firmware with the external trig input on the meter terminals.

The display on this guy is really dim. Any options for getting a brighter display? LED upgrade? Newer tube or ???.

The best external software for these I have found comes from Metratek; http://www.metratek.com/  That software also works with a number of other scopes including my 7854. The "p" version gets the power measurement features like the 720P.
 

Offline HighVoltage

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #116 on: November 21, 2016, 08:11:35 am »

The best external software for these I have found comes from Metratek; http://www.metratek.com/  That software also works with a number of other scopes including my 7854. The "p" version gets the power measurement features like the 720P.
I have never heard of this scope software before.
Has anyone here used it?
How much is the real version?
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Offline 1audio

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #117 on: November 21, 2016, 04:08:06 pm »
Metrateks web site is not the easiest to navigate here are the prices: http://www.metratek.com/price.html  You can download the demo version to make sure it works for you. I had the Tektronix software for the THS stuff but it was little more than a screen grabber. You still need that serial connection. I believe a USB to serial adapter will work. However the popular chip comes in two versions, one that works in the old XP world and one in the newer Win 7-10 world. Usually you don't know which you are getting on the cheap adapters. I have wasted many hours figuring this out. This is a helpful guideline: http://www.usconverters.com/index.php?main_page=page&id=62
 

Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #118 on: November 21, 2016, 05:50:06 pm »
It looks like I found the J1 connector

Molex 15-92-2480

the dimensions match with the drawing here:

http://www.molex.com/pdm_docs/sd/015922480_sd.pdf

...still waiting for the Adapter board... but now I have more hope than before...  It should be the right one...
« Last Edit: November 21, 2016, 06:41:48 pm by zucca »
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Offline BravoV

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #119 on: November 21, 2016, 06:57:51 pm »
Documenting the resistors mod, if you found any mistakes or not complete, just tell me, I will fix it accordingly.

Cmiiw, compared to 710A/720A/720P, it looks like 730A uses different AT1 and AT2 isn't it ? The ATx stands for attenuator ?  :-//
« Last Edit: November 21, 2016, 07:13:59 pm by BravoV »
 

Offline mk_

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Re: Tektronix THS720A Portable Scope Teardown/Discussion
« Reply #120 on: November 22, 2016, 04:29:31 pm »
I would also be interested in the little software app to capture the screen.

Best Wishes

Aurora

maybe this could be usefull...

Michael
 

Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #121 on: November 25, 2016, 06:59:37 pm »
FUUUUUUUUUUUU.....

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Offline BravoV

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #122 on: November 27, 2016, 01:11:47 pm »
Bummer  :palm: ... feel sorry for you Zucca.

Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #123 on: December 07, 2016, 09:18:48 pm »
It looks like I found the J1 connector

Molex 15-92-2480

the dimensions match with the drawing here:

http://www.molex.com/pdm_docs/sd/015922480_sd.pdf

...still waiting for the Adapter board... but now I have more hope than before...  It should be the right one...

well it is just BS! After further investigation it does  not match....

After two nights trying to find the right connector I give up... no way to find it on mouser or digikey. All the SCSI plugs are popping out... and our guy is not SCSI.
I found this

http://www.farnell.com/datasheets/1605497.pdf?_ga=1.116809280.799036234.1481144451

but it looks like it is not here either.

should I solder 40 cables on the back of that connector? Or buy another Plug+connector and desolder/replace the mister X J1 connector on the THS?

pffffff....
« Last Edit: December 07, 2016, 09:22:31 pm by zucca »
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Offline TurboTom

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #124 on: December 07, 2016, 10:12:03 pm »
Now that you already got that connector that' not wide enough apparently, why don't you just split it in half (place two slices of thin sheet metal between the contacts for protection and use a hacksaw between them to cut the plastic in half length-wise) and try to use the individual halves to make contact to the THS extension port. It may not work but it's worth a try I think.

Cheers,
Thomas
 

Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #125 on: December 11, 2016, 08:26:30 pm »
So.. what I will do next??? see attachment...
« Last Edit: December 12, 2016, 08:25:28 am by zucca »
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Offline mk_

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #126 on: December 11, 2016, 09:02:10 pm »
So.. what I will do next???


contact with spring-needles from the solderside? Solderdots could be 1,27mm-grid, so small needles should do it?

regards

Michael
 

Online TheSteve

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #127 on: December 11, 2016, 09:48:58 pm »
30 gauge wirewrap wire is your friend - run them all all to a dip socket that can plug into a programmer.

I wanted to read a BGA flash part in a device once without removing it. Being I had already torn one down I had mapped which testpoints matched which connections on the flash so I soldered 40+ wires to the bottom of the board. Those wires went to a PCB with headers on it. A second device also had a similar setup wired into that had a JTAG interface. I connected the two together via ribbon cables and used the JTAG interface in one to read the flash in the other device. The processor was held in reset to tristate its inputs.

Oh the fun, I also went through hundreds of feet of 30 gauge wire to wire in TSOP flash parts to replace BGA devices so I could remove the flash and rear/write to it.
« Last Edit: December 11, 2016, 10:02:22 pm by TheSteve »
VE7FM
 

Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #128 on: December 13, 2016, 10:05:18 pm »
30 gauge wirewrap wire is your friend - run them all all to a dip socket that can plug into a programmer.

this idea was already there... but you inspired me to the next level... well sort of... thanks!!!!



another step further....
 
« Last Edit: December 13, 2016, 10:06:59 pm by zucca »
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Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #129 on: December 16, 2016, 09:42:21 pm »
Well...  will it work?



Failed!



need to check the wires... tomorow..
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Offline BravoV

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #130 on: December 17, 2016, 04:15:40 am »
Zucca, just want you to know I really appreciate your efforts & sharing it here  :-+, guess I will keep popping the pop corns.  :popcorn:

Online TheSteve

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #131 on: December 17, 2016, 06:16:22 am »
I assume you didn't connect Vcc from the programmer to the scope, the processor is being held in reset and the scope is being powered from its power adapter?
VE7FM
 

Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #132 on: December 17, 2016, 03:14:47 pm »
Thanks TheSteve and BravoV to stay with me. I am just trying to give back something to this community.

So I checked all the wires on my adapter and they are OK. I also soldered the RESET PIN on the PIN 34 on J1.

The problem was I got the 12V on the DC Jack there, but I forgot to switch on the scope. There was no VCC on the board.

All the time the µC was in HALT state by connecting PIN 79, 78 on J1 together:



To switch on the scope simply connect the PIN 15 and 17 on the J6 adapter:



and I got 320mA flowing on the 12V... before well it was pretty much 0... stupid me. VCC was now there nicely at 5.01V.

I fired up the MiniPro SW with this options:



and I got this error message...



so fine I deactivated the check ID:



and bingo:



the problem now is the data looks like garbage, and between different readings the data changes...  :o

Here what I got (thx TiN for the FTP server):

https://doc.xdevs.com/doc/Tektronix/THS7xxx_Portable_scope/FW/1.14_try/

Now, maybe the "Erase befor" Setting wiped out the EEPROM before reading? I think no.. no waring nothing...
Another fishy thing is the Chip ID changes from time to time between 0x82 82 to 0x92 92 (sporadically)... who knows...

next step I try to pull together the scope and see if I bricked it..

UPDATE: It still works... :phew:

Don´t know why I am not getting the consistent reading from the EPROM reader... may the cable adapter is not properly shielded????





« Last Edit: December 17, 2016, 04:51:45 pm by zucca »
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Online TheSteve

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #133 on: December 17, 2016, 06:38:20 pm »
Could easily be noise - the wires are pretty long for what you're attempting. If the chip ID isn't 100% the same every time there is an issue. It could also be a bad connection but I am thinking noise more then anything. If you're up for making changes I'd suggest shortening the wiring to 1/3 of its original length - or as short as possible.
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Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #134 on: December 17, 2016, 06:53:46 pm »
Yep Steve you got it, I scoped out and the waves were shit...

Things are improving a lot when the 5V are feed on the J1 pin5 (not from the 12V DC Plug... )... after that I got sharp edges and cool digital signals.
It this case I got a reproducible FF all the time...

mmmm looks like the TL866 doesn't like this: OE (PIN 37 on the EEPROM) is internally generated by WE (PIN 35 on the J1 connector) in the scope.
There is a XOR which acts as a NOT, so OE=NOT (WE).

OE is not available on the J1 of course so I couldn't not connect it.

Unfortunately on the TL866 OE is something different than NOT(WE) and things are going  bad...

It could also be that the RY/BY (PIN 36 on the EEPROM) could play a role on the TL866 when programming the chip, and this is also not available on the bastard J1.

My conclusion: I think we need an external µC with a dedicated SW which can tap into the J1 and get the FW out... OR desolder the chip... 
« Last Edit: December 17, 2016, 08:02:45 pm by zucca »
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Online TheSteve

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #135 on: December 17, 2016, 06:57:58 pm »
Could you not directly solder just the OE wire to the flash chip itself?
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Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #136 on: December 17, 2016, 07:15:42 pm »
Could you not directly solder just the OE wire to the flash chip itself?

First of all we need to disconnect the output of the XOR and then we can tap in...  well this is going to be messy... I will just desolder U1 and done. No need to build an J1 adapter and so on...
« Last Edit: December 17, 2016, 07:46:32 pm by zucca »
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Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #137 on: December 21, 2016, 04:58:33 pm »
I ordered a air nozzle for the TSOP40 and the adapter for the TL866... I AM NOT GIVING UP.
Meanwhile a hero with a FW1.16 is needed so we can spread the last FW in the world: thinking on buying some U1 flash them and send those to you guys, anyone interested?

So while I am waiting for the parts to come in let´s modify the battery. I chose the 5000mA solution like posplayr did here.

Unhappy of that plus pole TEK crap patent solution, i decided to take apart the battery lid, wait a minute why no use a solder wick?



solder did not work there, no matter how much flux you out. So next step I press the solder wick between plastic and metal, to keep everything together I used hot glue which worked well (didn´t expect that)





then I soldered the plus cable, and there is even a little hook where the cable can be fixed on, thanks TEK!





Done:



Tested with 1.5A current the voltage drop af that thing is just 30mV... so cool.

Does the TEK have a reversal voltage protection if the battery is inserted other way? mmmm shottky diode?



 

« Last Edit: December 21, 2016, 05:05:22 pm by zucca »
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Offline mk_

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #138 on: December 21, 2016, 05:10:01 pm »

Meanwhile a hero with a FW1.16 is needed so we can spread the last FW in the world: thinking on buying some U1 flash them and send those to you guys, anyone interested?


Hm...  1.11 from a well running THS730A is the last I can offer (have to build adapter etc, so it will take time also), the others have 1.03 or 1.04 installed

regards

Michael
 

Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #139 on: December 21, 2016, 10:09:06 pm »
Hm...  1.11

Thanks Michael, but I have already the 1.14 Version... so we need someone with the 1.16
« Last Edit: December 21, 2016, 10:18:13 pm by zucca »
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Offline djnz

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #140 on: January 05, 2017, 04:38:20 pm »
I have recently acquired a THS720A and this is a very interesting thread indeed! It came without the serial cable, and I wish to make one. I read the whole thread and there are some pinouts given, but I was not able to understand clearly what the connections are. Different sources also seem to follow different numbering conventions, adding to my confusion. I am attaching a picture with the pins clearly marked and labelled 1,2,.., 8 and a,b,c,...,i. Could someone with a working cable please post what the connections are with reference to this naming convention. Thanks.

Edit:

1. With hard flagging and soft flagging both set to 'off' (no flow control), communication works fine with just Tx, Rx and Gnd connected, as expected. So,

                      3 <-----> d
                      4 <-----> c
                      5 <-----> a

seem to be sufficient.

2. With hard flagging set to 'on' (hardware flow control), communication seems to work fine with the following connections:

                      1 <-----> e & g
                8 & 2 <-----> h
                      3 <-----> d
                      4 <-----> c
                      5 <-----> a
                      6 <-----> i
                      7 <-----> b
                      8 <-----> h

Tested with a Keyspan USA-19HS serial-to-usb adapter which is male on its serial end.
 
« Last Edit: January 07, 2017, 05:44:54 am by djnz »
 

Offline mk_

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #141 on: January 05, 2017, 11:24:13 pm »
I have recently acquired a THS720A and this is a very interesting thread indeed! It came without the serial cable, and I wish to make one. I read the whole thread and there are some pinouts given, but I was not able to understand clearly what the connections are. Different sources also seem to follow different numbering conventions, adding to my confusion. I am attaching a picture with the pins clearly marked and labelled 1,2,.., 8 and a,b,c,...,i. Could someone with a working cable please post what the connections are with reference to this naming convention. Thanks.

Nice to meet you here

Did you download the schematic named THS7XXAPDiag.pdf? If so - look at pdf-page 9 and you find the RJ-Connector. 
http://kazus.ru/forums/attachment.php?attachmentid=25865&d=1315575619

There is also a file aviable called "THS720P Programmer Manual.pdf"
http://www.tek.com/oscilloscope/ths720a-manual/ths710a-ths720a-ths730a-ths720p-programmer-manual

 On pdf-page 18 you will find the pinassignments for the RS232.

Both files are too large for upload here to eevblog.

Michael
 

Offline BMack

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #142 on: January 06, 2017, 06:49:19 am »
I ordered a air nozzle for the TSOP40 and the adapter for the TL866... I AM NOT GIVING UP.
Meanwhile a hero with a FW1.16 is needed so we can spread the last FW in the world: thinking on buying some U1 flash them and send those to you guys, anyone interested?

So while I am waiting for the parts to come in let´s modify the battery. I chose the 5000mA solution like posplayr did here.

Unhappy of that plus pole TEK crap patent solution, i decided to take apart the battery lid, wait a minute why no use a solder wick?



Tested with 1.5A current the voltage drop af that thing is just 30mV... so cool.

Does the TEK have a reversal voltage protection if the battery is inserted other way? mmmm shottky diode?

Damn, that's a good idea. I rigged a sleeve that I can slide Eneloop C battery adapters into and used copper tape to make the contact.

I really wish I could get myself an extra stand for it, the stand was broken when I got mine.
« Last Edit: January 07, 2017, 06:23:22 am by BMack »
 

Offline 1audio

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #143 on: January 07, 2017, 12:46:40 am »
I found this assembled battery pack that is mostly ready to go for $15: http://www.batteryspace.com/nicdbatterypack48v30ah4xcendtoendwithtabs.aspx  It has tabs at each end. Its Nicad so it should work with the internal charger (or the external charger) with no problems once equipped with the connections. I'll need to either add the connection ring or modify the top connector to make it work. The connection ring is my first choice since I have one of the external chargers. I'll get one and try it if no one knows of a problem.
 

Offline 1audio

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #144 on: January 07, 2017, 12:48:37 am »
The screen on my THS720 is really dim. I am ready to replace the backlight tubes but only if the dim screen is abnormal. Do others have the same experience? Should I explore LED retrofit options?
 

Offline BMack

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #145 on: January 07, 2017, 06:27:17 am »
I found this assembled battery pack that is mostly ready to go for $15: http://www.batteryspace.com/nicdbatterypack48v30ah4xcendtoendwithtabs.aspx  It has tabs at each end. Its Nicad so it should work with the internal charger (or the external charger) with no problems once equipped with the connections. I'll need to either add the connection ring or modify the top connector to make it work. The connection ring is my first choice since I have one of the external chargers. I'll get one and try it if no one knows of a problem.

My original solution was a pack I made of rechargable C batteries. The 1.2V batteries would give me a "low power" warning after about 10 minutes. With the 1.5V Eneloops I get about an hour before the notification comes up. The C batteries wouldn't even last 40mins, Eneloops last about 90 mins.
 

Offline BravoV

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #146 on: January 07, 2017, 06:39:28 am »
My original solution was a pack I made of rechargable C batteries. The 1.2V batteries would give me a "low power" warning after about 10 minutes. With the 1.5V Eneloops I get about an hour before the notification comes up. The C batteries wouldn't even last 40mins, Eneloops last about 90 mins.

+1, ancient NiCd C cells simply can't beat current Eneloop AA cells when it comes to run times, not to mention the high self discharge of those NiCd type. As my 2nd post in this thread, I use Eneloop "Pro" which has even higher capacity than regular white ones.

The only disadvantage that I can think of is, we can not rely on the scope's internal charging to change modern NiMh cells, especially in series, and I worry it might toast them as it looks like the charging mechanism is using dumb slow constant current charging,  cmiiw.

Offline BravoV

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #147 on: January 07, 2017, 06:52:28 am »
I've been thinking if anyone with 3D drawing expertise could create a 3D model for the AA to C cells battery tube, as 3D printing service is becoming easier and cheaper these days.

Offline djnz

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #148 on: January 07, 2017, 08:56:42 pm »
I wrote a python program today for getting Hard Copy (screenshots) from these scopes in EPS Image format. I think EPS files handle resizing and PNG conversion well and thus and so they can be printed on paper at high dpi settings and used in reports etc..

I am attaching my zipped code as well as some EPS and EPS -> PNG samples obtained using the program.

Improvements and suggestions are welcome.
 

Offline BMack

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #149 on: January 09, 2017, 06:50:55 am »
My original solution was a pack I made of rechargable C batteries. The 1.2V batteries would give me a "low power" warning after about 10 minutes. With the 1.5V Eneloops I get about an hour before the notification comes up. The C batteries wouldn't even last 40mins, Eneloops last about 90 mins.

+1, ancient NiCd C cells simply can't beat current Eneloop AA cells when it comes to run times, not to mention the high self discharge of those NiCd type. As my 2nd post in this thread, I use Eneloop "Pro" which has even higher capacity than regular white ones.

The only disadvantage that I can think of is, we can not rely on the scope's internal charging to change modern NiMh cells, especially in series, and I worry it might toast them as it looks like the charging mechanism is using dumb slow constant current charging,  cmiiw.

I ended up designing he tub to push the batteries out through the bottom and charge in the normal Eneloop charger, then I keep four Eneloops in the case. Admittedly that's overkill because I have three scopes at home, and I can use three at work. The portable is for when I want a scope and the piece is too big for the workbench. Three hours of runtime should be enough for any portable scope.

Did you have an issue with the "Pro" cells fitting? I thought they were a little longer than the regular Eneloops.

If any of you have access to a 3D printer, that would be perfect for this. A C-sized tube with a AA-sized hole in the middle would work better than the C spacers...would also be great to fix my darn stand too >:(
 

Offline eKretz

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #150 on: January 09, 2017, 09:20:44 am »
Hey can some of you guys take a peek here and let me know how your Tek handhelds behave as regards this issue I'm having with my handheld scope?

https://www.eevblog.com/forum/testgear/dc-offset-wander/

You could easily have some battery adapters machined from nylon for those Teks too. If there are a few of you who want them I could probably make up a batch for you guys.
 

Offline HighVoltage

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #151 on: January 09, 2017, 09:40:57 am »
My Tek Handheld scopes do not show this behavior at all.
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Offline eKretz

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #152 on: January 09, 2017, 09:49:30 am »
I didn't think they would. My bench scope doesn't either. The seller is trying to downplay the issue though, telling me the trigger settings are wrong, lol. I took a couple videos of the handheld and my Tek bench scope being fed the exact same signal and will add them to the thread tomorrow. The Tek is rock solid with the same signal that has the handheld jumping all over the place.
 

Offline TurboTom

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #153 on: January 09, 2017, 10:18:12 am »
What about connecting the inputs of the Micsig and another oscilloscope directly together with a BNC-BNC cable to check if the offset problem is really present as a voltage at the input of the Micsig? If it is, it should be the best answer to the seller's doubts. BTW, I've also got one of the Micsigs and despite the input is not the most noiseless one, it's by far not as bad as yours. I assume the 20mV/div input voltage range you're referring to are with the probe factor configured 1:10, so it's a true 2mV/div.

Cheers,
Thomas
 

Offline eKretz

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #154 on: January 09, 2017, 10:34:36 am »
That's a good idea, but I don't have any hardware for that. I do have several BNC extensions though, I could probably cannibalize a couple of those and make one.

And yes, the probe factor is indeed set to 10:1 as my good probes are all 10:1, so in fact it's truly 2mV/div and 100mV/div that I'm looking at - but it's the same way on my Tek scope also.
 

Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #155 on: January 09, 2017, 04:14:29 pm »
The C batteries wouldn't even last 40mins

Did you use 5000 mAh NiMH C Batteries?

Should I explore LED retrofit options?

YES PLEASE!!!!  Very good idea, my display is ok. When the backlight tubes will say goodbye I will definitely put some LED there. There is also a place for a LED driver board if you toss the HV Tube inverter one...

 
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Offline 1audio

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #156 on: January 10, 2017, 06:26:40 am »
RE display lamps. I looked for LED solutions and there are many, but mostly for larger displays. I made a request to one outfit that seems promising for a more optimized solution. I would pay $35 for something that will just work over $15 and a lot of crude hacking to find it doesn't. If I hear back I'll post.

When the scope is unplugged and the battery is in it does it draw from the battery? Should I pull the battery when the scope will be sitting for a while?

For the deep cycle and repeated charging I have read the nicad is a better option. Nimh needs to be managed for max and min charge levels for long life. Toyota and Honda use 80% and 30% of max and min to get more life from the Nimh batteries.
 

Offline BMack

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #157 on: January 10, 2017, 07:26:22 am »
The C batteries wouldn't even last 40mins

Did you use 5000 mAh NiMH C Batteries?

Yes I did. I was expecting longer life or else I would have done Eneloops to start. The biggest problem is the annoying "Low battery" warning that comes up every few mins, it literally takes less than 10 minutes to start popping up.
« Last Edit: January 23, 2017, 08:16:31 am by BMack »
 

Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #158 on: January 10, 2017, 09:23:08 am »
The biggest problem is the annoying "Low battery" warning that comes up every few mins, it literally takes less than 10 minutes to start popping up.

I will investigate to reproduce this issue with my package, we are running with 5000mAh Bettery instead of the 2800mAh stock ones. It´s very surprising to me that this is happening. Surely the NiMH vs NiCd have different discharge ratings but jeeezzz...

I will perform a CSize 5Ah discharge test @1.2A (scope drain when on incl. Backlight) and report the results...

EDIT: Looking at the Spec. for Energized, Panasonic or other well know brand, a C Size NiMH is about 2500mAh-3200mAh... I am now thinking that 5000mAh are BS marketing....

Anyway

"Low Battery" warning appears at 4.6V. The power cuts off at 4.2V.

Interesting will be to know the power cut off time (@4.2V) comparison Csize 5000mAh vs 2000mAh Eneloop AA. Maybe you have already done this, 40min with Csize? CMIIW. In case the Csize will win... we could lower the low battery threshold by changing the R153 (close to U55) to a higher value (Low Battery when 4.3V or 4.4V).

To me it boils down to the following right now:

- 5000mAh C Size: no battery adapter required, compatible with internal scope charging circuit. Higher self discharging than eneloop. "LOW BATTERY" warning comes too soon (I 'll try to reproduce it)
- 2000mAh Eneloop AA: the opposite.

« Last Edit: January 10, 2017, 02:11:59 pm by zucca »
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Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #159 on: January 10, 2017, 09:27:52 am »
When the scope is unplugged and the battery is in it does it draw from the battery? Should I pull the battery when the scope will be sitting for a while?

According to my investigation in standby (OFF with battery inside), the current drain is 176µA.
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Offline BravoV

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #160 on: January 10, 2017, 02:15:09 pm »
Did you have an issue with the "Pro" cells fitting? I thought they were a little longer than the regular Eneloops.

Plain white Eneloop and the black Pro have identical dimension.

Its just Pro has "tad" higher self discharge rate than white one, no big deal imo, still much-much better than non LSD NiMh or NiCd.


If any of you have access to a 3D printer, that would be perfect for this. A C-sized tube with a AA-sized hole in the middle would work better than the C spacers...would also be great to fix my darn stand too >:(

+1
 
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Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #161 on: January 22, 2017, 09:14:51 am »
Thanks to ChippyZero we have a FW 1.16

not working...

Quote
This is an untested file that I pulled from a flaky THS720A.  I desoldered U1 using just enough heat to melt regular leaded solder and Chip Qwik low melt alloy.  Used self stick heatsinks and standard ESD prevention. Got a good read and verify using a TL866A.  When I copied the file to a new chip and installed it in the scope it would not initialize.  I reinstalled the original U1 and it acted the same way.  Don't know if the file is corrupt or if I somehow damaged the mainboard on the scope with my desoldering and soldering.  Use at your own risk!!

ftp://ftp.xdevs.com/Tektronix/THS7xxx_Portable_scope/FW/1.16/
« Last Edit: April 17, 2018, 06:35:36 pm by zucca »
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Offline z01z

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #162 on: January 23, 2017, 11:10:01 am »
Has anyone checked the contents of the file? The one I downloaded appears to be empty (0xff).
 

Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #163 on: January 26, 2017, 06:27:10 pm »
Has anyone checked the contents of the file? The one I downloaded appears to be empty (0xff).

same to me...  :-//
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Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #164 on: January 27, 2017, 11:02:32 am »
I will perform a CSize 5Ah discharge test @1.2A (scope drain when on incl. Backlight) and report the results...

So here we go. My batteries are these ones:

http://www.ebay.de/itm/291785752982?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

@CC 1.2A Discharge Test, I got the following:

4,6V Battery Low after 2 hours and 34 min
4,2 Cut off  after 2 hours and 58 min

Battery was charged 24 hours inside the Tek scope by 12VDC ext., left inside for more than 2 weeks. I turned on the scope 2 or 3 times for one minutes... just to see if I was already in battery low state, and I wasn't.I then took out the battery and performed the test this morning. At the beginning the battery voltage was 5,23V.

Attached the raw data.

So far no problem... now 'I'm recharging the batteries.
« Last Edit: March 28, 2017, 08:15:48 am by zucca »
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Online texaspyro

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #165 on: January 28, 2017, 06:14:59 am »
I have a THS730A.  Several years ago I made a replacement pack using 4500 mAh AccuEvolution LSD NiMh C cells.  These are high quality cells and not some over-spec'd Chinese junk.  It is still going strong.

I made the pack by taping a sleeve made of mylar around the cells.  For the positive contact I used some thin brass sheet from a hobby shop.  I cut it into a "L" shape.  The vertical part of the "L" is around 0.2" wide.  The end of the strip folds over the "+" of the top cell.  The bottom of the "L" is around an inch wide and wraps around the cells where the original battery contact is.

I taped the strip down and insulated it with Kapton tape.  The cells just slide into the mylar sleeve.  They are not tabbed together  and the springs in the scope press the cells together.  I do have a VERY nice CD welder that I built and intended to weld them together, but have never had a need or reason to do so.

I have always charged it in the scope without any problems.  I try not to leave it on charge for extended periods of time, but have occasionally left it charging for over a week...  the cells get pleasantly warm doing that but they don't seem to mind.

BTW,  I snagged the scope for less than $200 off of Ebay...
« Last Edit: January 28, 2017, 06:16:35 am by texaspyro »
 

Offline BMack

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #166 on: January 28, 2017, 07:04:18 am »
I will perform a CSize 5Ah discharge test @1.2A (scope drain when on incl. Backlight) and report the results...

So here we go. My batteries are these ones:

http://www.ebay.de/itm/291785752982?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

@CC 1.2A Discharge Test, I got the following:

4,6V Battery Low after 2 hours and 34 min beginning
4,2 Cut off  after 2 hours and 58 min from beginning

Battery was charged 24 hours inside the Tek scope by 12VDC ext., left inside for more than 2 weeks. I turned on the scope 2 or 3 times for one minutes... just to see if I was already in bettery low state, and I wasn't.I then took out the battery and performed the test this morning. At the beginning the battery voltage was 5,23V.

Attached the raw data.

So far no problem... now 'I'm recharging the batteries.

Wow, nice! So I guess we have a solution, buy Eneloops or other batteries that aren't these: https://www.amazon.com/gp/product/B00FHVM7GC/
 

Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #167 on: January 28, 2017, 09:29:01 am »
4500 mAh AccuEvolution LSD NiMh C cells.  These are high quality cells and not some over-spec'd Chinese junk.  It is still going strong.

Amen Brother!

Lesson learned: never trust the mAh on cheap no name battery. I am lucky than mines are roughly 3600mAh instead of 5000mAh, my BS detector had old firmare when I bought mines. Now I got the new FW on it...  ^-^ it will never happen again.   
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Offline HighVoltage

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #168 on: January 28, 2017, 11:19:04 am »

So here we go. My batteries are these ones:

http://www.ebay.de/itm/291785752982?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Those batteries look nice, I will try a set in one of my Tek scopes.
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Offline 1audio

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #169 on: June 22, 2017, 05:14:26 am »
Update on LED's for the LCD-
I got in a kit from China for "universal" LED update. Fitting it into the LCD is pretty easy BUT I found an issue in the manual (or in my scope). The manual says the supply voltage is 12V. It also references an incorrect pinout. Fortunately the schematics are correct once I found the connector in them. However its actually 5V. All the retrofit kits need 12V so that's an issue. There is a higher voltage available in the scope but I'm not sure where to get it and its -20V with limited current so not a great idea. Next step a 5V to 12V boost converter from China ($.99 w/ free shipping).  I'll need to find a cable since I don't want to destroy the existing cable.

So I'm reverting and installing a new FL lamp in the meantime.
 
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Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #170 on: June 22, 2017, 06:33:11 am »
...and of course you can't just replace some R in der LED module to accomodate the 5V input...

Thanks for the info! ... appreciate that.

Z
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Offline 1audio

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #171 on: June 22, 2017, 07:10:47 am »
Drat- even the new FL lamp doesn't fit. Its 3mm too long to fit properly. I spent an hour troubleshooting the orientation of the cable for the display. Not on top of things tonight. Probably the heat here. Even my battery got flakey.
 

Offline little_grey

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #172 on: July 14, 2017, 12:42:59 pm »
Hi all,

New to the forum, but been playing with scopes for work for years but recently acquired a THS710 all my very own.

mostly wanted to say thanks for all the tips and tricks, and i'll be sure to share my progress as and when i make some of the alterations.
 

Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #173 on: July 14, 2017, 12:53:25 pm »
Welcome little_grey,

I have everything now to desolder the U1 and trying to readout my FW 1.14 with a TL866A, but no time to attack the beast.
Do you thing I should try it? I hope the the FW is not locked down in the U1.
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Offline little_grey

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #174 on: July 14, 2017, 01:32:03 pm »
with all the hassle you have gone through so far to get connectors and alike.
you are so close.

that said, what would you want to achive once you have dumped the chip?

going to be using it primarily in the automotive world with hobbies along side, though used one when calibrating old equipment at Rolls-Royce.
 

Offline little_grey

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #175 on: July 24, 2017, 11:52:56 am »
finally got mine delivered and done a quick signal input test and reminding myself how the OS works.
Got the case and manual and what appears to be a fairly good battery for £230 so dont feel too out of pocket for it.

admittedly not the best bargain, the HP signal generator was £22 from a charity shop :D



i have some testing to do on coil and injector drivers later so i'll give it a proper working test later.
« Last Edit: July 24, 2017, 11:57:51 am by little_grey »
 

Offline grinch

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #176 on: August 11, 2017, 08:58:10 am »
Just my 2 cents. Original ths720 std power supply. Nothing special inside: rectifier bridge, resistor and capacitor:







« Last Edit: June 29, 2018, 12:14:54 pm by grinch »
 
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Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #177 on: August 11, 2017, 09:37:18 am »
Thx grinch, cheap ass stuff there...

that said, what would you want to achive once you have dumped the chip?

Upgrading to 1.16, If some gentleman will then dump out the 1.16 FW

and then reverse eng... something like this, checking and comparing the EPROM data

https://www.eevblog.com/forum/repair/quick-repair-standford-research-ps350-5kv-5ma-(fixed)/
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Offline SMdude

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #178 on: September 07, 2017, 01:12:53 pm »
Hey, just curious, has anybody tried to run one of these scopes from 8.4v from the battery input?
Looking at the schematic, I can't see a reason why it would not work as the 12v wall adaptor ends up feeding the same supply much higher than 4.8v.

Sure the built in charger won't work, though it could be modified for a higher output voltage, however the charger is really a mute point as I could contain one in the batt pack.

What I am thinking of doing is making a li-ion pack with 2 18650's  in series to get 8.4v with a built in 12v charger. I would use a piece of pvc pipe to house everything(without measuring, it looks about the right diameter).

The 15hr charge time for the ni-cd pack doesn't really turn me on, and it would be inconvenient to have more than one ni-cd pack as you'd be forever waiting for batteries to charge.

Cheers
 

Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #179 on: September 07, 2017, 01:29:22 pm »
Hope you can make your dream true. I wasted some time for exactly the same mod, but after I swapped the terrible aged Tek battery with news one (see some posts above) I was pretty happy and called it done deal.

Looking at the schematic, I can't see a reason why it would not work as the 12v wall adaptor ends up feeding the same supply much higher than 4.8v.

I see some components beetween the batteries pack and the 12VDC, so I will not be so 100% sure.
Easy test: take the battery out and feed the scope with the 12VDC jack, then measure the voltage at the empty batteries pack terminals. You will have the answer...

Be careful not to cook your scope with 8,4V experiments.

« Last Edit: September 07, 2017, 01:33:00 pm by zucca »
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Offline SMdude

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #180 on: September 07, 2017, 01:38:36 pm »
Well, at the output of the si9435(fet directly after batt pack), the voltage will be 1 diode drop below 12v.

Looking at everything else around there, I am feeling game. (almost)

Might take a smps and slowly ramp up the voltage while measuring current and see what happens.

Will let you all know what I find..

Cheers
 

Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #181 on: September 07, 2017, 02:04:12 pm »
Cool, yeah just ramp up the voltage at the batteries terminals and watch i.e. the scope 5V power rail if it will rise up above 5,5V I will call it a failed try....
« Last Edit: September 07, 2017, 02:07:47 pm by zucca »
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Offline little_grey

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #182 on: September 07, 2017, 02:32:29 pm »
i think i am with Zucca, for the price, i think i'll ether buy a complete replacement or replace the internal cells. that said my battery is not too bad at the moment.

if you are planning on running at a lower voltage are you going to be continually harassed by the low power warning? (might be missubnderstanding here)
 

Offline SMdude

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #183 on: September 07, 2017, 02:55:17 pm »
Nope, going for 8.4v as I have li-ion coming out of my ... shed!

Looking at the schema a bit further, I am very confident that this will work without any problems, just making the insert tube with the contact, then I will give it a try.

Grabbed myself some of these bms circuits(you should always use a bms with lithium) :
http://www.ebay.com/itm/2X-2S-3A-7-4-8-4V-Li-ion-18650-Lithium-Lipo-Battery-BMS-Protection-Board-PCB-EP/222612744056?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

And will be using a tp5100 charger board :
http://www.ebay.com/itm/2-cells-single-Lithium-ion-Battery-Charger-Module-1-2A-PCB-18650-TP5100-iphone-/171753145841?epid=1053965105&hash=item27fd4905f1:g:eL0AAOSwPhdVK8yD

With a 2.1mm dc jack,  and same polarity as the one that supplies the scope.

Will post more tomorrow arvo, late here now.

Cheers
 

Offline SMdude

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #184 on: September 08, 2017, 03:59:43 am »
Well, it works!
They have no problems running from 8.4v at the battery input.

Now to wait for the bms.

It's a bit rough, however it does the job.
Note to self, don't attempt to board a plane with it!  :-DD

Cheers

Ps, will let you know if the smoke comes out...

Pps, The low batt warning won't work unless it is modified for the higher voltage, but unless I have to pull it apart, CBF
 

Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #185 on: September 08, 2017, 08:10:38 am »
 :clap: :clap:

Battery C Size measures 50 millimetres (1.97 in) length and 26.2 millimetres (1.03 in) diameter. So the Tek Battery pack is about 20cm with 26.2 mm diameter.
A 25500 Liion Battey is about the same size as a C cell.

How about then 3x25500 in series... will the 12,6V burn up everything?  >:D Probably yes...

I found some 25500 with already the BMS integrated which is nice...
One questions... with 8,4V how much current does the Scope need?
I mean at 4,8V it needed 1.2A when full on (with backlight)... so at 8,4V maybe 1,2A*4,8V/8,4V=686mA? Probably yes..

wait with 12VDC on the charger jack it need about 500mA with no batteries attached... so probably it needs about 6W-5,8W (with backlight on!!!) to operate...  the rest is just math...

So quick battery life check:

2 18650 in series 3100mAh (SMdude mod)
3,1Ah/5,8W*(3,6V*2)= 3,84h

2 25500 in series 4000mAh
4Ah/5,8W*(3,6V*2) = 4,96h

3 25500 in series 4000mAh
4Ah/5,8W*(3,6V*3) = 7,44h

Now since according to my old post the 4 C-Size cell are lasting 2,96h you will get 3,84-2,96= 52 minutes more with the 2x18650. Which is nice, but I personally think it is not worth the effort unless you really need the quick charge feature.... and all the Liion bat goodies.

Much more interesting are the configurations 2x25500, and the porno dream will be the 3x25500 (it will last probably one business day and then the night comes where you will charge it)...

EDIT: a 26650 size is also very interesting.
« Last Edit: September 08, 2017, 03:13:20 pm by zucca »
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Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #186 on: September 08, 2017, 09:43:57 am »
I couldn't resist... according to my reverse eng... schematics page 15, near U55

R151/R153=Vlow/1,5V-1

Low Battery Liion warning mod... assuming 3,5V / Cell as trigger for the warning...

with 2 Liion
---> mod R151 with a 174,1KR
or
---> mod R153 with a 27,2KR

with 3 Liion
---> mod R151 with a 285KR
or
---> mod R153 with a 16,6KR



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Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #187 on: September 08, 2017, 03:19:24 pm »
Alleluja

http://www.ebay.de/itm/TangsFire-2pcs-6800mAh-26650-3-7-v-Lithium-Ionen-Akku-mit-PCB-Board-V1M4-/262876079813?hash=item3d34a2a6c5:g:zpoAAOSw~AVYtuvP

13,33€

2 26650 in series 6800mAh
6,8Ah/5,8W*(3,7V*2) = 8,67h

now we are in business, BUT I think the 6800mAh could be fake
« Last Edit: September 08, 2017, 03:21:11 pm by zucca »
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Online texaspyro

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #189 on: September 16, 2017, 01:02:56 am »
A few days ago I came across a THS730A battery pack that I built over 10 years ago using NiCd cells.   I never really used it since I had also built one out of 4500 mAh low-self-discharge Nimh cells (and that pack is still working).  A quick check showed the NiCd pack was toast, so I decided to rebuild it using NiMh cells.  A quick trip to the battery store found some 5000 mAh Imedieon low self discharge cells for a decent price ($25 / 4).  I've used Imedion cells for a long time and they work very well.

I rebuilt the NiCd pack (the way I built it,  just slid the old cells out of the mylar sleeve and slid in the new cells).  Then I went to test it in the scope.  I had some difficulty opening the battery door... WTF?  Turns out the door was broken.  The metal disk that connects the battery positive to the scope is held to the black plastic door with four TINY heat staked pins.  Three of the four had sheared off at the plastic knob.  I suspect that this will be a common failure mode.

So, I emailed Tek about a replacement door...  no joy... no longer available... support ended in 2012.

So I fixed the door / contact disk using IC2000 tire cement.  This is a rubberized superglue used to glue tires to wheels on RC race cars.   It is not brittle like regular superglue.   First I cleaned the metal disk and plastic knob with alcohol (190 proof Everclear grain alcohol is my cleaner of choice... non-toxic (in moderation) and it also makes a great screwdriver...  if mixed with orange juice and milk of magnesia is that a Philips screwdriver?). 

Next I scuffed up the back of the disk and the back edge face of the knob with rough sandpaper.  Then I applied a bead of IC2000 around the face of the plastic knob.  Finally, very carefully, I centered the disk on the knob.  Having one heat stake post still attached to the knob helped with centering the disk.  The battery door now works better than it ever did.   Unfortunately the little cloth tether that keeps the battery door attached to the machine has disappeared.  A little kevlar thread and some more IC2000 fixed that.
 

Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #190 on: September 16, 2017, 05:10:28 am »
If you look back you can find how I modified my battery pack.
I remove the metal disc intentionally and sandwich with hot glue some solder wick.
It's holding like a champ, I have then a wire for the positive pole and don't need the cloth tether.

Good to know about the IC2000.
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Online texaspyro

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #191 on: September 16, 2017, 01:14:20 pm »
I found the tether... it had slipped back in to the case and was hiding in its little cave.  A bit of shaking and tweezing coaxed it out.  I tacked it down to the metal disk with a drop of IC2000.   You do have to be a little careful closing the battery door.  The top of the brass strip is just folded over the edge of the battery.   The tether likes to settle between the battery positive terminal and the brass strip that runs down to the ring at the base of the battery stick.
 

Offline patpat

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #192 on: October 11, 2017, 05:10:47 pm »
My approach for using regular Eneloop Pro and spacers (or C size batteries) w/o altering the scope.
The Eneloops fit tight but I was able to close the lid w/o problem.
Now my THS730 works on regular AA (with spacers) or C sized batteries

This mod is good if do not need to change bateries very often.

Best,
Patrick
« Last Edit: October 11, 2017, 05:13:58 pm by patpat »
 

Offline jal1234

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #193 on: December 16, 2017, 11:49:08 pm »
I just replaced both polarizers on my LCD on my 720A that was illegible before I did it. I describe the process and what I used to do it at the end of this thread:

https://www.eevblog.com/forum/index.php?topic=53184.msg1376800.msg#1376800

Sent from my Nexus 5 using Tapatalk

 

Offline hardcoreman

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #194 on: December 31, 2017, 07:36:35 am »
hello, any progress with dumping firmware? :) i looking for 1.14 or 1.16.

i want try 710 to 710a mod. now i have working 710 to 720 v 1.03.

 flash size is same, pcb components same....
 

Offline patpat

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #195 on: January 06, 2018, 02:34:57 am »
I'm also interested in getting a FW dump.
I think J1 is the Fujitsu FCN-244M080-G/0
then we would need the female version of it i.e. FCN-244F080-G/0
Is anyone able to confirm this? I'm attaching the connector datasheet.

I also think the EPROM reader used by Zucca is not the right tool;
if we want to avoid a custom reader we should probably think of
something like i.e. the CONITEC GALEP-5 (Script Controlled) programmer,
controlling reading speed, uP HALT line, etc.
« Last Edit: January 06, 2018, 07:08:17 pm by patpat »
 

Offline hardcoreman

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #196 on: January 07, 2018, 11:23:15 am »
original on pcb is AMP brand...

but FCN-244M080 have same dimensions...
 

Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #197 on: January 07, 2018, 10:51:35 pm »
I have stopped the project because I am helping a friend of mine with a big project.
My plan is still to desolder the U1 and read it with the TL866, no more time wasted in the J1 jazz for me.

How many of you are waiting a FW dump? If a lot are interested I will reorganize my Todo list.
« Last Edit: January 07, 2018, 10:53:35 pm by zucca »
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Offline patpat

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #198 on: January 07, 2018, 11:42:35 pm »
If I were you I would not remove the connector, why would you do that?
<EDIT>sorry you mean removing the memory. my mistake.
If you can carefully do that sure will produce better results.
What I wrote next could be useful if you decide not removing the chip.
</EDIT>

When looking at your previous dumps it seems you have some additional problem on top of noise.
A noisy FW reading would look like a non-repeatable pseudo-random reading (68K code) but
yours does not look like reading the content of the memory at all.

You should check that the control lines are really selecting the "read mode" See
Table 1. Am29F080 User Bus Operations

Read Mode
The Am29F080 has two control functions which must
be satisfied in order to obtain data at the outputs. CE is
the power control and should be used for device selection.
OE is the output control and should be used to
gate data to the output pins if the device is selected.
Address access time (tACC) is equal to the delay
from stable addresses to valid output data. The chip
enable access time (tCE) is the delay from stable addresses
and stable CE to valid data at the output pins.
The output enable access time is the delay from the
falling edge of OE to valid data at the output pins (assuming the addresses


Next you should check that the RESET/HALT sequence really "works"

If you externally fix the control lines but the reader initializes the reading mode by "writing" the "reading command"
(see table Table 5. Am29F080 Command Definitions) you might be in trouble because the reader probably
does not have complete control of the device and that could very well lead to a non responsive memory.
The reader should be able to accordingly select the writing and reading control lines; remember in order to read
the reader could initially "write" the reading command.

« Last Edit: January 08, 2018, 10:06:39 am by patpat »
 

Offline superman13

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #199 on: April 13, 2018, 04:11:51 pm »
Hi!

Have anyone working firmware? Tried files 1.16, 1.14 and no success all files are empty.

Please if someone have possibility to dump memory I will be grateful. Next week I will get a dump for 1.08 but is very old version.
 

Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #200 on: April 13, 2018, 05:03:14 pm »
I am out of office until middle May. I will then try to do that. My plan is still to desolder the chip and read it out.

Even if we give you the FW dump now, how can you be sure it will work on your unit?
Moreover I assume you know how to de/solder SMD components.

Z

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Offline superman13

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #201 on: April 13, 2018, 05:47:32 pm »
I have two pieces of ts720A and one is working with 1.08 anotherone is dead (was with newer firmware)...
I desoldered both flash and soldered working flash with (1.08) to dead scope... And it is working. Memory from dead scope is alive... But I will try to clone it next week...

Will be very good if you can get newer firmware.
Next week I will post dump of 1.08.
 

Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #202 on: April 13, 2018, 06:50:54 pm »
Next week I will post dump of 1.08.

If it works please post all the process details, and then let the hunt for the FW 1.16 begin. I have only the 1.14.
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Offline BravoV

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #203 on: April 13, 2018, 06:53:32 pm »
Mine still at 1.11.  ::)


Offline superman13

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #204 on: April 13, 2018, 07:04:23 pm »
I will try to describe how to read flash... Problem is that dump will do one my friend who has socket, programmer and big experience with a lot of kinds of flash memory...

Will ask him to do some screenshots or photos.
 

Offline superman13

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #205 on: April 17, 2018, 01:41:21 pm »
Hi!
I have been cloned flash memory from old scope (1.08). And its working  :popcorn:

Flash was cloned using TL866.

I attached dump.

Will be perfect if someone can get dump of newer firmware  :-/O

https://drive.google.com/open?id=1yST43Pc7M_PxNIg4uqZ_9FiX2KKyKmao

Photos: https://photos.app.goo.gl/VDiYyJWrB1dgEPtp2


« Last Edit: April 17, 2018, 01:43:14 pm by superman13 »
 
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Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #206 on: April 17, 2018, 01:48:24 pm »
superman13

Thanks, as soon I go back in my Lab in May I will unleash the 1.14 FW.
The FW 1.16 hunt is officially open, I will updated the thread title and first post.

Did you recalibrated the unit? As far as I now in that chip there are also the calibrations parameters.
« Last Edit: April 17, 2018, 01:53:59 pm by zucca »
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Offline superman13

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #207 on: April 17, 2018, 01:55:33 pm »
superman13

Thanks, as soon I go back in my Lab in May I will unleash the 1.14 FW.
The FW 1.16 hunt is officially open, I will update the thread title and first post.

Did you recalibrated the unit? As far as I now in that chip there are also the calibrations parameters.

I have to calibrate it but now I have to buy another display, because one of my THS720 has broken LCD. But these lcd's are still expensive  |O

PS. Tried someone to replace LCD with another one more accessible, newer, cheaper? :D
 

Offline BravoV

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #208 on: April 17, 2018, 02:05:35 pm »
Did you recalibrated the unit? As far as I now in that chip there are also the calibrations parameters.

Really wish there is a way to copy the calibration values ... :'(

Offline jal1234

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superman13

Thanks, as soon I go back in my Lab in May I will unleash the 1.14 FW.
The FW 1.16 hunt is officially open, I will update the thread title and first post.

Did you recalibrated the unit? As far as I now in that chip there are also the calibrations parameters.

I have to calibrate it but now I have to buy another display, because one of my THS720 has broken LCD. But these lcd's are still expensive  |O

PS. Tried someone to replace LCD with another one more accessible, newer, cheaper? :D
Is the LCD dead, or are the polarizers bad?  I successfully replaced both polarizers on mine with no prior experience. Time consuming, but not that difficult.
 

Offline superman13

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Is the LCD dead, or are the polarizers bad?  I successfully replaced both polarizers on mine with no prior experience. Time consuming, but not that difficult.

It's broken  :horse:

 

Offline jal1234

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Is the LCD dead, or are the polarizers bad?  I successfully replaced both polarizers on mine with no prior experience. Time consuming, but not that difficult.

It's broken  :horse:


Oh well. Yeah, with new LCDs selling for $150 US on eBay, and whole 720s with accessories selling (I'm talking what units actually sold for, not the insane prices some people ask) for $300-350 or so, it's tough to justify.
 

Offline Zucca

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #212 on: April 17, 2018, 06:42:54 pm »
Really wish there is a way to copy the calibration values ... :'(

My unit needs to be calibrated anyway and the calibration procedure it is not so difficoult... Actually it's not so bad to recalibrate the unit after a while...

Anyway I will readout the FW before and after the calibration so we can see what does it change.
I am sure there is a CRC somewhere too...
« Last Edit: April 17, 2018, 06:48:19 pm by zucca »
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Offline BravoV

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #213 on: April 17, 2018, 06:44:27 pm »
My unit needs to be calibrated anyway and the calibration procedure it is not so difficoult... Actually it's not so bad to recalibrate the unit after a while...

Really, if its not troubling you too much, please, share the recalibration process here.

Anyway I will readout the FW before and after the calibration so we can see what does it changed.
I am sure there is a CRC somewhere too...

Thank you  :-+ , looking forward to see the results.

Offline Zucca

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Offline BravoV

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I'm aware of that document, its just I don't have the supporting equipments as the minimum requirements to do that.

Offline Zucca

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Quote
156--6553--00 U1 IC, MEMORY; CMOS, FLASH;1MEG X 8,
120NS;E28F008SA, TSOP40

Flash memory which contains instrument
firmware, current setup, saved setups, saved
waveforms, saved data, waveforms, and
calibration constants.

We need to find out where the serial number and the calibrations parameters are... and then save them out.

 :-/O

It`s just a matter of time if some guys are playing with us here.
« Last Edit: April 17, 2018, 07:20:40 pm by zucca »
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Offline Zucca

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I don't have the supporting equipments as the minimum requirements to do that.

Me neither... It would be an home made calibration... better than nothing.
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Offline Zucca

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Offline z01z

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We need to find out where the serial number and the calibrations parameters are... and then save them out.
Well, it should be easy to locate the calibration parameters if one can dump the contents of the flash before and after calibration.
 

Offline superman13

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I want to buy this scope from ebay to take DUMP of 1.16 (as I see from photos) and for display, one of mine scope have broken lcd... but this lot is too expensive and I have made an offer for 150$...

https://www.ebay.com/itm/Tektronix-THS730A-200MHz-Scope-DMM-Digital-Real-Time-1GS-s/163006175519?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055359.m2763.l2649

So, who can and want dump of firmware, please make offer for less than ~100$, hoping that seller will accept my 150$ offer  :-/O

In that case I will get DUMP from this scope and i'm that THS730 has the same firmware as THS710, 720 :)
If anyone knows if there are different firmwares, please let us know about this.
 

Online PA0PBZ

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In that case I will get DUMP from this scope and i'm that THS730 has the same firmware as THS710, 720 :)
If anyone knows if there are different firmwares, please let us know about this.

I found this in the firmware:

TDS 320
TDS 350
TDS 310
TDS 340
TDS 360
TDS 380
THS710A
THS720A
THS720P
THS730A
Keyboard error: Press F1 to continue.
 

Offline HighVoltage

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I have a THS720P with FW 1.16

What is involved in reading out the FW?
There are 3 kinds of people in this world, those who can count and those who can not.
 

Offline superman13

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I have a THS720P with FW 1.16

What is involved in reading out the FW?

You have to unsolder  U1 (AM29F080) and using an external programmer with corresponding adapter to read it...

I don't know exactly how to make dump because it was done by one friend who has TL866, but I think there should be some info how to make dump of that kind of mem.
 

Offline Zucca

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Moreover you need the TSOP-40 adapter for the TL866, and I have a TSOP-40 hot air nozzle to disolder that chip properly.
I just need to go back at my lab.
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Offline HighVoltage

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zucca,
Should I send you my 720P, so you can read the FW out?
There are 3 kinds of people in this world, those who can count and those who can not.
 
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Offline Zucca

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YES!!!
HV can read my mind.
I will send you my DMM7510 as a small thank you...

Let´s talk about this in May when I will be back home.
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Offline HighVoltage

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Great!
Let me know, when you are ready.

There are 3 kinds of people in this world, those who can count and those who can not.
 

Offline sky2city

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I have one THS720A, with FW 1.11.  then I upgrade it to 720P, it work.
thanks you guys.

 

Offline grinch

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hello again,

just changed old, crumbly molded foam insert in the case by a "new" one. Second hand packing foam was used. if someone needs sizes of original foam see images.

hope it helps.

« Last Edit: June 29, 2018, 05:07:44 pm by grinch »
 
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Offline Zucca

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Nice!

Sorry guys, I got a girlfriend and all my planes are arse up now.
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Offline BravoV

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YES!!!
HV can read my mind.
I will send you my DMM7510 as a small thank you...

Let´s talk about this in May when I will be back home.

Zucca, hows the progress on extracting the firmware ?

Offline Zucca

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0%.

That girl and work are sucking all my time.
« Last Edit: June 30, 2018, 11:24:59 am by zucca »
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Offline BravoV

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0%.

That girl and work is sucking all my time.

LOL .. ok , take your time, and TIA for doing this, also to HighVoltage, you guys rock.  :clap:  :-+

Offline HighVoltage

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@zucca
I just came back from a long trip and can send it out any time now.
But you might need more time with the new GF.
Just let me know, when you are ready.
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Offline Zucca

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HV

guess what, I am on business trip in Leipzig until end of August... so away from my Lab again for 2 months.  :'(
Can't know what you don't love. St. Augustine
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Offline HighVoltage

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Ohh, you are busy guy these days.
No problem, just let me know, when time permits.
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Offline analogRF

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #237 on: August 27, 2018, 03:22:11 pm »
When I received my (then) THS710A, both scope channels showed some DC offset that changed with the input sensitivity ranges selected. DC path compensation didn't correct this and I read somewhere in the forum that this is relateds to "worn out" analog optocouplers (CNR-201A) that are used to transfer the DC component of the input signal across the isolation barrier. Since these components are not particularly expensive. I decided to get some and replace them.

Guess what the result was: Same picture as before  :o

As a last resort I thought the complete factory calibration of the scope section might possibly help, and fortunately, it did the trick!  DC offset vanished completely. ;D

I just wanted to post the information in this thread since it seems to be the most comprehensive and as I understand, many of the THS700 models suffer more or less severely from the DC offset over the time. Calibration is very simple and all that's required for the job is a good (arbitrary) function generator that's capable of outputting a square wave with half-way decent rise time (<20ns) and a DC voltage (the accuracy of the latter should be checked with a reliable multimeter).  Fortunately, the scope section and the DMM section of the THS700 is calibrated separately and the DMM section calibration is very unlike to deteriorate over time.

All the information required for the job is available in the service manual, starting at page 51: http://de.tek.com/oscilloscope/ths720a-manual/ths710a-ths720a-ths730a-ths720p-service-manual

My recommendation in case of DC offset problems is to try this calibration before swapping out any components, especially since removal of the analog isolators is a real PITA....

Cheers,
Thomas


P.S. Some calibration steps really take some time and the instrument may appear like it's crashed -- just get yourself a cup of coffee (or whatever you feel like having at the time...) and wait. The screen contrast is set to 50% during calibration, on my THS700 this results in a rather dim screen (normally it's set at 65%), so don't worry if something like this happens.

Hi TurboTom
I understand this is a very old thread but I was hoping you or someone on this thread can help. I have a THS720A with the same DC offset issues. I have done the calibration as you suggested twice but the offset comes back after a short while. It is good right after calibration but in an hour or two it comes back again. Any suggestion? Should I go for replacing the optocouplers?

thanks
 

Offline Zucca

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analogRF

I have also the DC offset problem. I still need to recalibrate the unit and see what happens.

Do you see it in both channels? If not swap the opto and see what happen.

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Offline analogRF

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no its just one channel. the other one is fine. I did the calibration twice and it was good for like 1-2 hours (even without using the scope for any measurements) and the offset came back.

Have you tried replacing the optocoupler? some people say it works and some have not been successful.
I am sure if it is replaced the unit definitely needs re-calibration and that should be the case with replacing any component in the signal path (otherwise it will probably show an offset and even a wrong gain) but re-calibration without replacing the opto has not worked for me so far.

Is there any other component that might be the suspect?
 

Offline Zucca

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No, I still need to calibrate the unit and see what happen then.

Mark the suspected opto with a sharpie, desolder both of them.
If you are in the mood you can test them in a separate board outside the device, just to do some sanity check.

If nothing comes out and swap them out and do the calibration again. You will see if the problem stays with the bad opto or not.

Are the power supply rails good on the bad channel?

Even if I tell you my suspects list you NEED to make some measurement and investigate yourself where the problem is.
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Offline TurboTom

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Re: Tektronix THS7xxx Portable Scope Hack/Teardown/Discussion
« Reply #241 on: August 29, 2018, 08:56:28 am »
Hi TurboTom
I understand this is a very old thread but I was hoping you or someone on this thread can help. I have a THS720A with the same DC offset issues. I have done the calibration as you suggested twice but the offset comes back after a short while. It is good right after calibration but in an hour or two it comes back again. Any suggestion? Should I go for replacing the optocouplers?

thanks

Just pulled my old THS710 "+" from the shelf where it collects dust (...) and powered it up. Surprise, surprise -- seems like there's no offset drift. Right after turning on, both traces were within +- 0.2 DIV center (as far as it's visible on that crappy screen) when zapping through the ranges. ANd they also stayed there after some prolonged time of operation. I've got to add, I power the instrument from a switcher wall-wart with a fairly stable output, so battery drain or so isn't taken into consideration here. And as reported, I replaced all the analog optocouplers in the isolated frontends. If that made a difference for the long-time stability of mine -- my guess is as good as yours.

Since the optocouplers aren't that expensive, it may be worth a try if you're good at soldewring in the confinded space next to the shielding boxes... Would I do it again if I had to?  -Probably not, too many scoped around (bad case of TEA... ) and the THS700 really looks old-fashioned meanwhile. The power analysis function available after the hack may be useful once in a while tough.

Cheers,
Thomas
 
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Offline wingerr

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Are there any pictures of the opto isolator in its natural habitat?
I'm going to go fiddle with it as my channel 1 is reading several negative kV. Don't know if there's a layout diagram available.
My firmware is v1.06, must have gotten one of the earliest ones.
 

Offline TurboTom

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@wingerr: Zucca posted a nice high-res photo of his EPROM readout setup a few pages ago that you can magnify and cut to get the board almost full-screen. You see the analog couplers (the four wider ones -- HCPL-201A) directly next to the input amp shielding cans. I wasn't able to remove the cans for optocoupler replacement so soldering in the new ones is quite a bit of surgery... IIRC, I cut the old ones out, removed the terminals individually, cleaned the pads and then swapped in the new ones. You will need the gull-winged versions.

 
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Offline analogRF

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why those cans/shields could not be taken out? 
Are the components inside them soldered directly on the main pcb and the cans are just shields? or they are completely shielded hybrid modules with separate pcb inside and only some pins coming out?

 

Offline TurboTom

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There are just too many substantial ground tabs soldered in the PCB. The PCB is a multilayer with a lot of copper for grounding in this area and I just didn't want to risk damaging it. With some pre-heating it's surely possible to get the cans out. It's just a question which way is less tedious. For my own part I decided that I'll be able to replace the couplers without removing the cans which (for me) turned out to be the right decision.
 

Offline Jim Narem

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Picture of an attenuator with the shield removed is here:  http://w140.com/tekwiki/wiki/File:Ths720std-scopeanalog.JPG.  There are other internal pictures of my unit (which is a STD, not an A) on the primary tekwiki page at http://w140.com/tekwiki/wiki/THS720

I used metcal hot tweezers with wide tips to do mine, another method is to use chip-quik with a hot air gun.  Clipping the pins is probably the easiest solution if you only have a soldering iron.

Usually only the output optoisolators (U45, U46) need to be replaced.  The two others (U50, U63) are reversed, they supply the attenuator with an isolated offset signal generated by the  DAC multiplexer U5.  They will all eventually wear out due to the ageing  characteristics of the LEDs in the optocouplers.  Not sure how good the long term supply of these parts will be due to the HP/Avago/Broadcom saga.
 

Offline analogRF

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Picture of an attenuator with the shield removed is here:  http://w140.com/tekwiki/wiki/File:Ths720std-scopeanalog.JPG.  There are other internal pictures of my unit (which is a STD, not an A) on the primary tekwiki page at http://w140.com/tekwiki/wiki/THS720

I used metcal hot tweezers with wide tips to do mine, another method is to use chip-quik with a hot air gun.  Clipping the pins is probably the easiest solution if you only have a soldering iron.

Usually only the output optoisolators (U45, U46) need to be replaced.  The two others (U50, U63) are reversed, they supply the attenuator with an isolated offset signal generated by the  DAC multiplexer U5.  They will all eventually wear out due to the ageing  characteristics of the LEDs in the optocouplers.  Not sure how good the long term supply of these parts will be due to the HP/Avago/Broadcom saga.

Thanks for the great pictures. Actually I had seen and downloaded them from tekwiki long ago but somehow I had forgotten all about them.
Anyhow, I have a question about the offset issue although currently I am experiencing another problem on top of the offset issue which I'll explain in another post
I always thought U50 and U63 must be the culprits for the offset problem. Specially if the offset value changes with range, I suppose it must be going through the attenuators and therefore it must be coming from U50/U63. It seems to me if the offset is added by U46/U45 then you have a fixed amount of offset "divisions" on screen in all ranges. Am I wrong? At least in my case the offset value changes with range.
Now if my understanding is correct, I wonder why shouldn't we be looking at U53/U74 opamp? If that opamp has developed offset over time that can equally mess up the offset voltage the same way that U50/U63 do.
 

Offline analogRF

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I did more experiments with my THS scope and now I can see I have two distinct issues which I have not seen discussed before. Hope someone could give me a clue as to how to go about repairing it.

1-The offset issue on channel 1: I have done the scope calibration twice and numerous SPC and the offset always "comes back" (read below) although it is much smaller than it used to be. Also the offset value changes with range.
However, yesterday I noticed something that must have been there all along. When I plug in the power adapter, the offset gradually, over 2-3 minutes, disappears! and when I unplug it, it takes 2-3 minutes for the offset to slowly come back. The batteries are brand new and fully charged and their voltage is solid. How can that be?

2-"High pass" type of response on channel 1: the bigger issue that I have with the scope is the freq response of channel 1. I connected my function gen with square waveform and a piece of coax with no termination directly to the scope. On channel 2, everything is honky dory on all ranges, the top/bottom of the pulses are flat and the gain is accurate and when I switch to sinusoidal the gain is perfect on all ranges. However, on channel 1 with the same setup, "only" on the two ranges (100mV-500mv and 10V-50V) the top and bottom of square wave is exponential with overshoot. When the wave period is long enough the voltage settles to the correct value, so the DC gain is OK (I have checked with DC voltage and the gain is perfectly ok) but if I increase the frequency it does not have enough time to settle so the square wave appears to have a larger amplitude than it should. And if I inject sine wave the gain is clearly wrong (larger than it must be) on those two ranges.

I tried to measure the input impedance of the scope ports by connecting my LCR meter. On the good channel I get something around 28.05-28.3pF on all ranges (it changes about 0.25-0.3pF when jumping between the ranges) but on the bad channel I get 30.9pF on the two "bad" ranges and 28.08pF on the two good ranges. The scope spec is 25+/-2pF and I had to insert a BNC-SMA adapter in order to connect my LCR meter tweezers, so I know 1-2pF error must be ok but I cannot explain the inconsistency on those two bad ranges on channel 1

One thing to note is that in those two ranges the X10 attenuator kicks in while in other ranges either there is no attenuator or only the X100 attenuator is in the signal path.

Any suggestions?
 

Offline Jim Narem

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I don't fully understand the operation of the scope, and I did this back in 2014, but when I instrumented the board and ran the cal proceedure it seemed that the signal passed IN to the atten board (called POS1 and POS2 in the CLIP schematic, generated by the DAC and passed by U50 and U63) changed the feedback loop on the optocoupler  going OUT of the atten board.  You need to read the datasheet on the HCNR201-300E optocoupler to see how the second photodiode is used to linearize the system.  After I replaced the OUT optocoupler, the cal process passed.  I watched the cal process by using a logic analyzer on the DAC to trigger a scope looking at the POS signal and the feedback line on the OUT optocoupler.  With that setup, I could see the cal stepping the POS signal voltage and failing out due to lack of range.  It may be possible that replacing either of the optocouplers may fix the problem; again, eventually both will have to be replaced due to ageing of the LEDs.

You can run the board outside the case to probe around, see my picture here:  http://w140.com/tekwiki/wiki/File:Ths720std-runningboard.jpg.  A differential probe is needed to see the useful signals.  I think I used a peltola to SMA adaptor to feed signals in to the atten board.

My scope always takes some time to warm up, initially with some negative offset, then I do an SPC and it's fine.

Your second problem sounds like a failing relay in the attenuator.  The RF cover isn't too hard to remove with chip-quik and a solder sucker and the relays were available last I checked in 2014.  The relays and the AC coupling cap are really the only things that mere mortals can repair on that atten board, so it's worth a try.
 

Offline capt bullshot

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One thing to note is that in those two ranges the X10 attenuator kicks in while in other ranges either there is no attenuator or only the X100 attenuator is in the signal path.
Any suggestions?

Yes, should be quite obvious: There's an issue with the X10 attenuator. Maybe a capacitor gone bad. The usual scope attenuator is a parallel connection of a high impedance resistive divider and a capacitive divider of the same ratio. If DC is OK, I'd believe the resistors are still OK, but if you've got a deviation at AC, there's a mismatch in the capacitors. Older Tek scopes had the capacitors as trimmer caps, while in these ceramic hybrids the resistors get adjusted during the manufacturing process.
I guess you'll have to remove the ceramic hybrid from the PCB to gain access to the capacitors, either they are underneath the relays, or on the other side of the ceramic.

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Offline analogRF

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Thanks @Jim Narem for the detailed response. Yes, I can see either of the optocouplers can cause the offset problem
right now the offset is small and I can deal with that later but my major concern is the messed up frequency response of channel 1
it  seems the input capacitance changes to wrong value in two vertical ranges when the X10 attenuator kicks in
my suspicion is also the relay (the middle one) but I cannot quite figure out how/why the relay can cause
capacitance imbalance? I can see it might cause unwanted contact resistance but capacitance? how?

on the other hand, as you said, there is not much else on the attenuator board since the elements are all laser etched or something
It's also hard to imagine one of those integrated capacitors has changed its value over time
 

Offline analogRF

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One thing to note is that in those two ranges the X10 attenuator kicks in while in other ranges either there is no attenuator or only the X100 attenuator is in the signal path.
Any suggestions?

Yes, should be quite obvious: There's an issue with the X10 attenuator. Maybe a capacitor gone bad. The usual scope attenuator is a parallel connection of a high impedance resistive divider and a capacitive divider of the same ratio. If DC is OK, I'd believe the resistors are still OK, but if you've got a deviation at AC, there's a mismatch in the capacitors. Older Tek scopes had the capacitors as trimmer caps, while in these ceramic hybrids the resistors get adjusted during the manufacturing process.
I guess you'll have to remove the ceramic hybrid from the PCB to gain access to the capacitors, either they are underneath the relays, or on the other side of the ceramic.

don't you think the capacitors are also integrated inside the ceramic pcb? I mean like they are eatched into the circuit board?
if they are underneath the attenuator, there  is hope !

also, can it be due to the relay as @Jim Narem suggests? Although i cannot figure out how the relay can cause imbalance capacitance
 

Offline analogRF

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....I think this might be how it works: there is a series C (or RC) between the input and output of the relay. when the X10 atten is out, the relay is closed and that series RC is short circuited and when the X10 atten kicks in, the relay is open and the series RC (or C) between the I/O of relay comes in to the signal path (parallel to the series branch of the attenuator ). So, that capacitor is probably at fault here not the relay itself.

If that capacitor is a discrete component underneath the hybrid, i might have a chance but i don't know what the value should be.

this problem seems very similar the issue people have had with Siglent SDS1202X-E early models for which a remedy was also discussed extensively on the forum but I dont know how exactly they modified the circuit....i do have that scope myself and it has that issue but I didn't care to fix it. never affected my work really...
 

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Offline capt bullshot

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don't you think the capacitors are also integrated inside the ceramic pcb? I mean like they are eatched into the circuit board?
if they are underneath the attenuator, there  is hope !
I've never taken a look into the shielded attenuators of these THS scopes myself, so I just was guessing. One can see a few capacitors soldered to the ceramic, especially the big one for AC coupling as I suppose. I've replaced the relays in my TDS580 attenuators (found some pictures here: https://www.eevblog.com/forum/testgear/tektronix-tds520b-attenuator-swap/ ), here one clearly can see the large metallized areas - these are the capacitors for their attenuators, see the laser trimming. I don't know wether the THS ceramics are made the same way or they've soldered discrete capacitors. For sure, one can see laser trimmed resistors there (Edit: looked again at the high res picture, looks like a trimming scheme applied to whatever is hidden under the blue coating, can't tell if it's a capacitor or resistor).

Quote

also, can it be due to the relay as @Jim Narem suggests? Although i cannot figure out how the relay can cause imbalance capacitance

From my opinion / experience, a weak relay should cause DC errors. Within the TDS 5xx / 7xx attenuators, weak relays cause SPC errors, and/or complete loss of signal for some attenuation settings. Exercising the relays can cure that for a while.
« Last Edit: September 11, 2018, 01:18:56 pm by capt bullshot »
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Offline analogRF

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You know we have the schematics, don't you?

https://www.eevblog.com/forum/testgear/tektronix-ths700-tekscope-component-level-information-package-and-schematic/

of course. But my frequency response problem is inside the attenuator hybrid (marked as AT1 on schematics) so the schematics don't help ....see the pictures posted by @Jim Narem  at http://w140.com/tekwiki/wiki/THS720
 

Offline analogRF

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@capt bullshot: I also believe the caps are etched into the ceramic. I highly doubt there is anything underneath that board.
SPC passes on my scope with no problem and DC is perfectly fine on all vertical ranges. Only when I apply a square wave with long enough period I can see on those two ranges the pulses have a exponential riding on top of them with overshoot and then settling down to the correct value.
Scope calibration didnt help either as most of the process only uses DC voltages.

I wonder what might have happened to a ceramic etched capacitor to go bad?
 

Offline capt bullshot

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@capt bullshot: I also believe the caps are etched into the ceramic. I highly doubt there is anything underneath that board.
SPC passes on my scope with no problem and DC is perfectly fine on all vertical ranges. Only when I apply a square wave with long enough period I can see on those two ranges the pulses have a exponential riding on top of them with overshoot and then settling down to the correct value.
Scope calibration didnt help either as most of the process only uses DC voltages.

I wonder what might have happened to a ceramic etched capacitor to go bad?

Overvoltage? Environment (humidity)?
One of the laser cut links may have gone short again for whatever reason?

I've had some defective ceramic caps in an old 7 series plug-in: http://wunderkis.de/tek-7/ Don't know what caused them to go bad either.

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