Author Topic: Tektronix 2465B oscilloscope teardown  (Read 469755 times)

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Offline AMR Labs

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1425 on: February 11, 2019, 03:38:24 pm »
Manuals should be useful on all versions but one thing to keep in mind is the 2465B differences from SN 50001 and up which are important to consider. There are also some individual components that where changed at some specific serial number range. This info would be only available mostly in the later 2465B/2467B manual.

Have you tried this download link?

http://w140.com/tek_2465B_2467B.pdf
 
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Offline Satbeginner

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1426 on: February 11, 2019, 03:42:07 pm »
Hi,

you are right where it comes to the scopes, there are differences with respect to the S/N, but I believe the Options Service manual is generic for all scopes.
I never found another Options manual, but if it exist, I for sure want a copy :-)

Un saludo,

Leo
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*Tek 2467B, Tek 2465B, Tek 2465B, Tek 485, Tek 475A,  Keithley 175A, Keithley 2000, HP 3468B, HP 3457A, HP 34401A, PM 6671, PM 5716, Fluke 45, Fluke 75, Fluke 77, Fluke 79, AFX 9660BL, KPS 605D, etc. *
 

Offline jonpaul

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1427 on: February 11, 2019, 04:24:29 pm »
Hello all: Yes used the 2465 opt proceedue to cal 2465B CTT, AOK! Perhaps the 2465B OPT man is vapro.

Can anyone please address my non-manual issues b/ c/  posted a few messages/hours back?

____________________

b/  old issue:  This 2465B CTT op 06 (SN 066xxx) is  losing the panel settings at next turn on and default to 50 mv/DIV AC coupling etc regardless of previous settings.   I believe that this symptom existed before the old NV RAM failed and was replaced. Besides CAL data does the NVRAM also get FP settings written at shutdown?  Since NV RAM is new and works and the scope seems to initialize and shutdown normally, what can cause this symptom?

c/ Misc cleanup:

A5 board options connector J4241 mates to the option ribbon cable with 2 connectors on the A5 end and 2 more with greater separation on options end. That links A5 to CTT options board. At A5,  The second connector and thick cable loop interferes with the NVRAM as the machine pin socket raises it a bit. Any reason not to just cutoff the unused connectors?

The Fan is a bit noisy, replacement is the NIDEC Beta SL?  Many models exist, as fan is critical to cooling, have 12V 0.12 and 12V 0.16 A models. Any tips on best replacement part?

Usual dead graticule lamps, any pitfalls in replacing? Suggest the original incandescent lamps or try LEDs?

MANY THANKS AGAIN!

Jon
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Offline MarkL

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1428 on: February 11, 2019, 06:02:19 pm »
b/  old issue:  This 2465B CTT op 06 (SN 066xxx) is  losing the panel settings at next turn on and default to 50 mv/DIV AC coupling etc regardless of previous settings.   I believe that this symptom existed before the old NV RAM failed and was replaced. Besides CAL data does the NVRAM also get FP settings written at shutdown?  Since NV RAM is new and works and the scope seems to initialize and shutdown normally, what can cause this symptom?
Take a look at EXER 06 in the diagnostic menu.  This allows you to select either SETUP 1 or the power-down configuration when powering on.  COUPLING UP selects between the two.  Sounds like it's set to SETUP 1.

Quote
c/ Misc cleanup:

A5 board options connector J4241 mates to the option ribbon cable with 2 connectors on the A5 end and 2 more with greater separation on options end. That links A5 to CTT options board. At A5,  The second connector and thick cable loop interferes with the NVRAM as the machine pin socket raises it a bit. Any reason not to just cutoff the unused connectors?
Offhand I wouldn't go cutting off any connectors.

Perhaps a photo of the issue?
 

Offline jonpaul

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1429 on: February 11, 2019, 07:04:39 pm »
Dear MarkL!

WOW perfect, indeed  EXER 06 was on SETUP 1. Changed to  initialize to last settings. MANY THANKS!

Last issues (I hope).......

1/  Fan is noisy, replacement is the NIDEC Beta SL? 
Many such NIDEC models exist, I have 12V 0.12 and 12V 0.16 A spares. Any tips on best replacement part?

2/ Usual dead graticule lamps, any pitfalls in replacing? Suggest the original incandescent lamps or LEDs?

With Kind Regards,

Jon
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Re: Tektronix 2465B oscilloscope teardown
« Reply #1430 on: February 11, 2019, 07:49:21 pm »
I would suspect that either fan is probably OK. At least the fan is easy to service on the 2465B. Not so the case on the 2465. If you want to get real anal about it and determine which fan is best you can perform an experiment similar to what I did here:

https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/msg1215559/#msg1215559

I attached a thermocouple to the rear plate near the power supply and then ran the sweep at high speed to get U800 good and hot then monitored the temp. Never rose above 97 F (36 C) in ambient 72 F (22 C). And you can "smoke test" the airflow from the bottom vents which are directly below U800. That's really the most important is to maintain that airflow. If you can "see" the airflow with the smoke it's probably OK.

Hope this helps. As far as the graticule lamps I've never had to change one. 
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Offline MarkL

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1431 on: February 11, 2019, 08:34:21 pm »
Dear MarkL!

WOW perfect, indeed  EXER 06 was on SETUP 1. Changed to  initialize to last settings. MANY THANKS!

Last issues (I hope).......

1/  Fan is noisy, replacement is the NIDEC Beta SL? 
Many such NIDEC models exist, I have 12V 0.12 and 12V 0.16 A spares. Any tips on best replacement part?

2/ Usual dead graticule lamps, any pitfalls in replacing? Suggest the original incandescent lamps or LEDs?

With Kind Regards,

Jon
You're welcome!

I have a Nidec Beta SL in my 2465, D08G-12TH, 12VDC 0.16A.  But it doesn't look like it's a factory installation to me.  If your Nidec spares work and aren't noisy (yet), go for it.  I slipped a little bit of thin neoprene sheet underneath the areas where it contacts the chassis to reduce noise even further.

I've never replaced a graticule light.  Perhaps someone who has can answer that one.  Personally, I like the look of the old incandescent lamps.
 

Online LADmachining

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1432 on: February 13, 2019, 11:04:56 am »
Thanks to all of the contributors so far, this has been a good read of the previous 58 pages of the journeys people have had to take to restore their scopes.

I have now joined the party and acquired a 2445B.  Due to serial number confusion I was expecting a model with the SMD A5 board and DS1225, but instead got an earlier model with through-hole A5 and Keeper battery.  Last calibration of the scope was performed by Tek in 1999, and the tamper seals were still intact, so it hasn't been apart in the intervening period.  The unit 10K hours and approx 3K power-up cycles.

Firstly, before knowing this didn't have a NVRAM, I captured and recorded the cal data using EXER02.  The Keeper battery reads 3.5V still (date code 0689), but I think it is still prudent to replace it.  Will follow the guides available to change it out, but the question is what to, as the LTC-7P is not easily available in the UK.  Other LiSOCl2 cells are available, it is just choosing which type to use.

Has anybody looked into how the 6264 RAM could be reprogrammed with cal data if the worst happened and it was corrupted or cleared accidentally?  I guess you could solder wires directly to the chip with a CR2032 and diode, and transfer it between a programmer and the A5 board after reloading the cal data.  Does the cal data sit at the same address in RAM (0x1E00 to 0x1FFF) as on the DS1225?

Could the 6264 RAM be replaced with a DS1225 - pinout is the same apart from pin 26 which is CE2 on the RAM and NC on the DS1225?

Enough questions, here are pictures of the machine question...

« Last Edit: February 13, 2019, 12:41:01 pm by LADmachining »
 

Offline jonpaul

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1433 on: February 13, 2019, 12:29:45 pm »
Hello MarkL and med6753!

progress update,  Have total 4, the working units are a 2467 IEEE  and  another 2467B
Both 2465B CTT/2467B needed A5 board cap damage and NVRAM fixes and  restoration.
All low hours (2K, 3K, 8K) physical/cosmetic excellent.

0/ Analog calibration:  set 10.000 V REF and DAC REF (+/- 1.25V) procedure. Notice the initial settings if you do this!

1/ FAN: original Nidec 12V 0.16A still useable. Substitutes had wrong current or low airflow.
Peel paper label, drop of oil on  ball-bearing. Added 0.035" thk 1.5" dia neoprene between the fan hub and sheetmetal rear bracket.
Fine for noise.  PS: Old fans (soldiers) never die, they just fade away (apologies to Gnl Douglas McArthur).

1A/ Heat/U800: Seems a lot of notes and some disagreement re the original U800 thermal desing and lifetime.
2467B original U800, no heatsink, 2465B  original TEK U800,  resoldered or replaced in the dim past, with a small heatsink.
Temps seem cool. QUESTIONS: a. setup to check worst case U800 temp, fastest sweep rate?
b. With no HS and TEK U800, what typical temp are recorded with cabinet closed? Cabinet open?

2/ CAL: After A5 rework and load new NVRAM with default image, 2465B was CTT FAIL, after CTT CAL, ALL PASS!
Check: Vert ampl ~ 2-5% all ranges,  HOR ~ 1%. Useable but need CAL. Fast rise edge response OK (PG506) but need TD pulser for HF/Edge CAL. Trise ~ 900 nS.

After CAL, unplugged both NVRAMs,  to read and save NVROM images. (used XGecu "MiniPro" TL866CS programmer $40)

3/ LAMP: Graticule lamps: 5.0V 0.115A T-3/4 40,000 hrs 7153AS15 at  DK 7153AS15-10PK-ND pack of 10!

4/ PSU: All units seem fine, PSU voltages and ripple OK. Visual of RIFA caps and lytics seem OK. To the 2465/7X PSU veterans and rebuliders:

a/ Leave it alone or recap? b/ Time/tools/pitfalls to pull and rework PSU? c/ BOM: Source for caps, special resistors, rectifiers, etc?


For some years, and last few months,  I worked on these scopes, with fine components, gold PCBs, complex but easy to service mechanical and well written documentation.

As I reread the manuals and did some CAl, I realized what a fantastic quality design the TEK engineers did.
Amazing that these machines (1980s..early 1990s)  still work perfectly, there is no modern replacement!
What a contrast to the minimum cost/life/performance digital Chinese junk marketed today with deceptive specs and compliance.

Again many thanks to all for the great feedback and support info.


Jon

PS: Please see my SIGSALY first ADC recreation in February IEEE Spectrum:

https://spectrum.ieee.org/geek-life/hands-on/rebuilding-a-piece-of-the-first-digital-voice-scrambler
https://spectrum.ieee.org/geek-life/hands-on/sigsaly-analogtodigital-converter-construction-and-debugging

Your comments and feedback appreciated.





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Re: Tektronix 2465B oscilloscope teardown
« Reply #1434 on: February 13, 2019, 12:59:56 pm »
I can answer 2 of your questions.

U800: LEAVE IT ALONE. If you read back through this thread there's lots of opinions. But the consensus seems to be that adding heatsinks DON'T help. In fact, they may inhibit cooling. U800 depends upon AIRFLOW to keep it within it's operating temp. That's achieved by keeping the cooling system in good shape. Things such as dust free and a running fan. And don't run the scope outside the case any longer than necessary because there's inadequate airflow with the case off.

I highly recommend recapping the PSU. Here's the link. I also attached the parts list.

https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/msg1658102/#msg1658102 
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Offline jonpaul

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1435 on: February 13, 2019, 03:00:27 pm »
med6753, wow, fast and perfect answer!

1/ U800: Rodger that, cannot understand the overheating posts.

2/ PSU: Wonderful rebuild, you are the expert. I have some NOS Sprague radial caps, but they might be dried out. BOPM XLS is a great aid. Approx time you needed to PSU  rebuild?

3/ EDGE:  response with TEK TD pulser (drive:  PG506), about perfect. Very wary of HF response tweaks (LEAVE IT ALONE?)

4/ FAN: On the 2467, with Siemens hall effect fan, (a bit noisy), any way to lube bearings besides complete disassembly and rewind?

Cheers,

Jon


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Re: Tektronix 2465B oscilloscope teardown
« Reply #1436 on: February 13, 2019, 04:42:38 pm »
If you hustle you can do the PSU recap in one day. But I don't recommend that because you can easily introduce errors. Plan on 2 days.

If you are satisfied that you can't get the wave form looking any better then I would leave it as is....unless it's grossly out of spec.

The Seimens fan motor: Yes, it is possible to restore operation of this motor without tearing it down. You can get lucky like I did here:

https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/msg1861713/#msg1861713

But if that fix doesn't work you can follow mnem's excellent pictorial of tearing down the motor starting here:

https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/msg1863798/#msg1863798





 
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Offline jonpaul

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1437 on: February 14, 2019, 03:10:13 pm »
Hello All:  This was posted on eevblog elsewhere, thought you may enjoy:

----Please see my SIGSALY 1942  ADC recreation with tubes, in February IEEE Spectrum:

Printed magazine has the first link article.

https://spectrum.ieee.org/geek-life/hands-on/rebuilding-a-piece-of-the-first-digital-voice-scrambler
https://spectrum.ieee.org/geek-life/hands-on/sigsaly-analogtodigital-converter-construction-and-debugging

Your comments and feedback appreciated.

Jon -----
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Offline MarkL

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1438 on: February 14, 2019, 08:22:36 pm »
...
Has anybody looked into how the 6264 RAM could be reprogrammed with cal data if the worst happened and it was corrupted or cleared accidentally?  I guess you could solder wires directly to the chip with a CR2032 and diode, and transfer it between a programmer and the A5 board after reloading the cal data.  Does the cal data sit at the same address in RAM (0x1E00 to 0x1FFF) as on the DS1225?
The cal data still sits at those locations.

If you have a EPROM programmer, it should be possible to write a very simple 6802 assembly program to set up the ROM SELECT and PAGE SELECT latches, and then write the 512 bytes directly into 0x1E00 to 0x1FFF.  I made a couple of attempts at writing the program, but someone else was trying it on their scope because I didn't have an A or B scope to test it.  I do now.  It's on my list.  But if you can do 6802 assembler, it should be a no-brainer.

Quote
Could the 6264 RAM be replaced with a DS1225 - pinout is the same apart from pin 26 which is CE2 on the RAM and NC on the DS1225?
I don't have the 2445B schematics to know for sure, but after looking at the 2445A schematics which use a keeper battery, and the 2465B schematics which use the DS1225, it looks like it would work.  CE2 is only used as an enable once the +5V is stable and nRESET is high.  The DS1225 has an internal enable controlled by the Vcc voltage so it doesn't really need the protection function that CE2 provides.
 
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Online BravoV

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Tektronix 2465
« Reply #1439 on: February 15, 2019, 07:45:14 am »
New upcoming "home-work"  ::), a dead fail to power on, 2465 with Option 10 & 11, missing 2 front feet, 4 front knobs and also top cover thin plastic that covers the opening for accessing the filter screen, looks like previous owner replaced the blue with clear acrylic, and forgot to install it back.

Anyone got spare knobs ?  :P
« Last Edit: February 15, 2019, 07:50:09 am by BravoV »
 

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1440 on: February 15, 2019, 10:38:13 am »
Hello all: End of the long A5/NVRAM/recalibration/restoration of my 2465B/2467B rebuild:

HOR and other CAL seem OK.  But Vert Cal. CH 1/2 cal  ~ 2-5% error consistent error per scope/channel on all deflection factors.

Test Equipment: TM510, PG506, TD pulser, 50 ohm atten, precision cable, etc.

Asking you veteran TEK gurus for tips or pitfalls in CAL 02, I have seen posts with errors in various CAL procedures, but lost track the exact sections and errors. 

Many thanks!

Jon
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Re: Tektronix 2465B oscilloscope teardown
« Reply #1441 on: February 15, 2019, 12:40:18 pm »
I stumbled across this video 2 days ago and all I can say is "Wow!" |O  It took him 3X as long to service those RIFA caps than it should have. He didn't realize that the entire Regulator/Inverter board assembly would pull out as one unit just by removing 2 screws on the back plate and 3 screws down by the heat sink.   :palm:

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Online med6753

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Re: Tektronix 2465
« Reply #1442 on: February 15, 2019, 12:58:09 pm »
New upcoming "home-work"  ::), a dead fail to power on, 2465 with Option 10 & 11, missing 2 front feet, 4 front knobs and also top cover thin plastic that covers the opening for accessing the filter screen, looks like previous owner replaced the blue with clear acrylic, and forgot to install it back.

Anyone got spare knobs ?  :P

I've used these guys in the past for some Tek parts and they seem to have a good selection of knobs for the 24XX series.

https://www.qservice.tv/
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Offline jonpaul

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1443 on: February 16, 2019, 10:05:22 am »
Dear med6753 and others: Many thanks for the notes. Before CAL 02, doing CAL 01, HOR, the timing off  ~ 3%.

Reading the CAL 01 procedure, some steps have confusing instructions, I  found the forum note re CAL 01  3 undocumented steps "..manual shows 31 steps for CAL 01, but the 2465B actually has 34 steps. After  completing the 31 steps, advance through 32, 33,  and 34...

Am using TM501, any other pitfalls or tips for a novice in CAL 01?

Many thanks again!

Jon
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Offline jonpaul

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1444 on: February 18, 2019, 10:17:06 am »
Hello all:  RE U800, temps

Scared to overheat U800 during full CAL.

From Chuck Harris at https://groups.io/g/TekScopes/

...At 25C ambient, U800 runs 49C with the scope... 46C with case installed.... U800 would..handle 30C + 46C = 76C  max specified ambient.

1/ working on 2465/7B, with  original TEK U800s. U800 runs cool.
Continuous op at highest H sweep would be a worst case temp  of U800? Any temp measurements running on the 5ns/div sweep?

2/ Doing a full (or even partial) CAL requires cover off and preliminary 20 min warmup. Procedures can take hours and U800 and other hybrids on A1 could overheat.

3/ Placing an external fan on A1 mainboard could cool the A1 board below normal op temp in the case.

So there seems to be contradictions in cooling when doing long CAL.

I appreciate any recommendations and observations from the 2465B veterans  re cover/external fan/cooling  during a CAL 01/02 or full cal for cover, warmup and external fan.

Many thanks again!

Jon
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Re: Tektronix 2465B oscilloscope teardown
« Reply #1445 on: February 18, 2019, 02:50:45 pm »
Hello all:  RE U800, temps

Scared to overheat U800 during full CAL.

From Chuck Harris at https://groups.io/g/TekScopes/

...At 25C ambient, U800 runs 49C with the scope... 46C with case installed.... U800 would..handle 30C + 46C = 76C  max specified ambient.

1/ working on 2465/7B, with  original TEK U800s. U800 runs cool.
Continuous op at highest H sweep would be a worst case temp  of U800? Any temp measurements running on the 5ns/div sweep?

2/ Doing a full (or even partial) CAL requires cover off and preliminary 20 min warmup. Procedures can take hours and U800 and other hybrids on A1 could overheat.

3/ Placing an external fan on A1 mainboard could cool the A1 board below normal op temp in the case.

So there seems to be contradictions in cooling when doing long CAL.

I appreciate any recommendations and observations from the 2465B veterans  re cover/external fan/cooling  during a CAL 01/02 or full cal for cover, warmup and external fan.

Many thanks again!

Jon
See replies #6 and 12. Read carefully. All you need to know is there.  ;)
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Re: Tektronix 2465B oscilloscope teardown
« Reply #1446 on: February 18, 2019, 03:09:49 pm »
"See replies #6 and 12. Read carefully. All you need to know is there.  ;)"

Unsure you mean PAGE 6, 12 of the 58 pages or how to locate, by date?

Links to those replies appreciated!

MANY THANKS

Jon
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Re: Tektronix 2465B oscilloscope teardown
« Reply #1447 on: February 18, 2019, 03:12:00 pm »
"See replies #6 and 12. Read carefully. All you need to know is there.  ;)"

Unsure you mean PAGE 6, 12 of the 58 pages or how to locate, by date?

Links to those replies appreciated!

MANY THANKS

Jon
On page 1.
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Online med6753

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1448 on: February 18, 2019, 04:20:36 pm »
"See replies #6 and 12. Read carefully. All you need to know is there.  ;)"

Unsure you mean PAGE 6, 12 of the 58 pages or how to locate, by date?

Links to those replies appreciated!

MANY THANKS

Jon
On page 1.

As tautech just pointed out (Page 1 of this thread) and as I have said. Airflow is the most important element in keeping U800 cool.

Now, having said that. Yes, a full calibration can take a long time and the case is off. I personally have not had to do a full cal on either of my 2465's. But if I were I would rig a fan pointed at the A1 board. Now it may not be absolutely necessary but it certainly couldn't hurt.
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Offline jonpaul

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1449 on: February 21, 2019, 11:50:29 pm »
Hello there: Just an update: On 2465B, CAL procedure, HOR CAL was off ~ 1-4%.

1/  CAL 01: Good instructions, just a few that I puzzled over the routine.

Equip:  TM501, and 2467 as bench scope. 3 steps hit limits, fixed by the repeat of those steps.

About 1 hr for CAL 01. Checked HOR timing afterwards, perfect!


2/Cover off CAL cooling: During HOR CAL 01, about 2 hrs total, all IC, Hybrid HS and U800 temps just slightly warm, did not need an external fan.

Next for the easier CAL 02.

Many thanks to all for their fine CAL notes!

Enjoy!

Jon
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