Author Topic: Conversion Tektronix TDS500 to TDS700 color oscilloscope  (Read 4253 times)

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Offline zxase258

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Conversion Tektronix TDS500 to TDS700 color oscilloscope
« on: February 02, 2018, 04:11:33 pm »
In model TDS500B/C/D has been successfully tested.
TDS500 and 700 series, in the same model, they have the same firmware and acquisition system, and similar processor board.
Only need to add and change some components, you can change TDS500 series to TDS700 series.
Before you upgrade, you should first install the color LCD monitor via the VGA out connector.
(A similar project (Simmconn Labs) to this topic, he uses FPGA reads display memory, and "color" the data. This solution is too complicated and expensive. :-BROKE)
TDS520B -> TDS724A
TDS540B -> TDS754A
TDS520C -> TDS724C
TDS540C -> TDS754C
TDS580C -> TDS784C
TDS520D -> TDS724D
TDS540D -> TDS754D
TDS580D -> TDS784D

For TDS500B series(All changes are on the processor board).
remove:R12(model ID) R151 & R152 & R153
replace:U251 74F04 to U250
install:U837 & U835 & U836 & U834       TC528257J-70   Video RAM













For TDS500C/D series(All changes are on the processor board).
It has been a long time since I finished this work. I have forgotten which resistors I changed (for the model ID).
The following two pictures are used to compare their differences, please try it yourself. :palm:
replace:U251 74F04 to U250
install:U834 & U835 & U836 & U837       TC528257J-70 or M548263-60J   Video RAM

















Soldering SOJ packages is a bit difficult, make sure they are soldered reliably. Otherwise there will be a vertical line or flashing display.





enjoy it.  :D
« Last Edit: February 02, 2018, 04:17:59 pm by zxase258 »
 
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Online Jwalling

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Re: Conversion Tektronix TDS500 to TDS700 color oscilloscope
« Reply #1 on: February 02, 2018, 08:44:08 pm »
I always knew this was possible, but I never attempted it as it was way too much work given what these are worth now!
You sir, get a high-five! :-+

If your scope has an acquisition raw board (700C/D and 500C/D I think) that only has 64Kb SRAMs and that's capable of using 1Mb SRAMS, your next mission could be to replace all the memory and get option 2M!   ;)
Jay

System error. Strike any user to continue.
 

Offline chihaxinh

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Re: Conversion Tektronix TDS500 to TDS700 color oscilloscope
« Reply #2 on: February 05, 2018, 08:48:03 am »
Hi zxase258

I have one osc 520B like you . Scope have error Display and can't complate boot , can you share me your firmware of TDS 520B ?

And when hacking mod 520B to 724A only replace position resistor ?

Thank so much !
Nam Nguyen Hai
 

Offline zxase258

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Re: Conversion Tektronix TDS500 to TDS700 color oscilloscope
« Reply #3 on: February 12, 2018, 10:30:18 am »
Sorry, TDS520B transformation completed in 2015, at that time I do not know the firmware can be backed up. Later this scope was sold by me. :-//
Of course, in my experience, the oscilloscope's firmware is rarely damaged. Can you talk about the symptoms?
 

Offline zxase258

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Re: Conversion Tektronix TDS500 to TDS700 color oscilloscope
« Reply #4 on: February 12, 2018, 10:39:29 am »
The principle should be feasible, but to solder a lot of SRAM chips, some difficulties, and SRAM prices are not cheap.
For the DPO series, fv6.6 firmware (or higher) is shipped from the factory and 2M optional SRAMs are normally installed, so these models can be directly enabled with the 2M option.
 

Offline chihaxinh

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Re: Conversion Tektronix TDS500 to TDS700 color oscilloscope
« Reply #5 on: February 23, 2018, 09:09:31 am »
Hi zxase258

My scope fail display PCB , i disconnect connector from main pcb to display pcb, and using LCD external . Display in boot process very slow and display green color . No relay clicking , and no led front panel blinking. Boot process not complate

Many tks you !
Nam.
 

Offline induzer

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Re: Conversion Tektronix TDS500 to TDS700 color oscilloscope
« Reply #6 on: February 28, 2019, 07:59:32 pm »
I did a conversion of my TDS540D to TDS754D some weeks ago.
I can state the modifications zxase258 wrote to be partly correct, but maybe not complete.

Adding the VRAM - soldering was easier I thought.

Swapping U251 to U250 - rubbish on CRT (like lost sync, ic handles some picture timing signal, see service manual), no picture on VGA [timing critical part, my replacement ic was some nanoseconds too slow  :-[ ]

Swap back 250/251 - i belive it was white blank on CRT, but colour scope screen on VGA.

So far, fine.
But the scope boots up with one minor error about missing or wrong VRAM registers. Think there is some further action needed.
Maybe its missing the circuitry for the NuColor shutter system, a QFP and 3  VRAM-like footprints in the video section are not populated. Factory 745D have them populated.

serial boot debug:

Quote
dsyPM011RegMem ................. ***FAIL*** ..error details:
ERRORID: 163 diagnostic test failure dsyPM011RegMem ** addr = 0x75ed808  exp data = 0x7f00  actual = 0xff00
Failure in first PM011 vdramal register

Apart from that and after replacing a brick CAL-EEPROM and recalibration, the scope works fine with a 19" color screen via the rear VGA port.

Lucky me, so I can read the screen without my glasses, which I often set off while debugging :-DD

greeting, induzer   :-+
 

Offline induzer

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Re: Conversion Tektronix TDS500 to TDS700 color oscilloscope
« Reply #7 on: February 28, 2019, 10:41:52 pm »
Had a quick look at the schematics.

It's definite the missing frame buffers VRAMs U820 to U822 and the ASIC U2011 (National ADG281)

U822 is also called PM011, see my fault code in the last post. Missed that until now  :-[


So the following Parts need to be modified for 540D to 754D conversion (all on CPU board):

- CHANGE the ID resistors like shown in picture and table

- INSERT U834 & U835 & U836 & U837 + U820 & U821 & U822 == TC528257J-70 or M548263-60J   Video RAM

- TRY REMOVE U251 == 74F04
- TRY INSERT U250 == 74F04 (use fast ic or save U251)
  (crt picture, see my earlier experiences)

- INSERT U2011 == ADG281 == MM9351-VCE

If you can live with error an selftest and are happy with external screen only, leave U2011 & U820 & U821 & U822 open.
As far as I can speak for my own scope, it does not affect the meaurement.


Maybe someone will proof that I got confused while playing around with U250 / U251 for saving the internal screen functional. :-//

induzer :-/O


« Last Edit: February 28, 2019, 10:55:48 pm by induzer »
 

Offline PerpetualWalnut

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Re: Conversion Tektronix TDS500 to TDS700 color oscilloscope
« Reply #8 on: March 03, 2019, 12:38:35 am »
Do you know any good places to find the vram chips and the ASIC? I guess I could wait and find a fried 754C CPU board on ebay.

I also tried just changing the jumper settings without the other mods and it boots up as the 754C with a flashing color screen on the VGA output and a completly white CRT the first time I booted it up, then on the second time I booted it up the CRT was mostly white but had the text on display.
« Last Edit: March 03, 2019, 12:43:06 am by PerpetualWalnut »
 

Offline PerpetualWalnut

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Re: Conversion Tektronix TDS500 to TDS700 color oscilloscope
« Reply #9 on: March 08, 2019, 01:29:51 am »
Okay! I've substituted the TC528257J-70 vram chips with TC528267J-60 and it works just fine. The TC528267J-60 chips where half the price on ebay. As for the ASIC I haven't been able to get one yet. The scope powers on in 754 mode with the built in CRT displaying Text on white background with no waveform, and the VGA out displays full color without error.

It does fail the processor self test when run manually but everything else seem to work fine. I guess this might have something to do with the missing ASIC chip. Maybe if someone here has a dead board they are willing to de-solder one of the ASICs and send one my way? Ill buy! Plus beer if your in the DFW area.

I guess I would also need U193. Lots of NOS tlc34075 on ebay from what it looks like!

I should also add that moving U251 to U250 causes the internal display to go out of sync while doing nothing for the VGA output. So for now I'm just going to leave it at U251. The Internal display is white but the VGA output is still in color. LUCKILY! Putting the jumper resistors back to the 540C config allows it to work fine even after adding the addition ram chips!
« Last Edit: March 08, 2019, 01:51:10 am by PerpetualWalnut »
 

Offline PerpetualWalnut

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Re: Conversion Tektronix TDS500 to TDS700 color oscilloscope
« Reply #10 on: March 25, 2019, 02:19:09 am »
So!! I switched out and installed U193 and now nothing appears on the built in CRT but the VGA out still works.  :-/O I probably still need the ASIC, probably. I also need U260 which is a 74F08. Weird that they depict it in the schematics as a NOR gate with inverted inputs. Does the same thing though.  :-// I went ahead and ordered a couple off digikey and should be here within the week. They can hitch a ride with my LED COB WHT 5600K 95CRI 1214-1267-ND for anyone interested, but that's for another project. >:D Hope this helps anyone else. My goal is to have a converted TDS 754 that still has a functioning CRT with the option of upgrading to a color CRT or LCD swap in the future. I could do an LCD swap now, but that's boring.
 

Offline zxase258

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Re: Conversion Tektronix TDS500 to TDS700 color oscilloscope
« Reply #11 on: August 20, 2019, 02:48:39 am »
Had a quick look at the schematics.

It's definite the missing frame buffers VRAMs U820 to U822 and the ASIC U2011 (National ADG281)

U822 is also called PM011, see my fault code in the last post. Missed that until now  :-[


So the following Parts need to be modified for 540D to 754D conversion (all on CPU board):

- CHANGE the ID resistors like shown in picture and table

- INSERT U834 & U835 & U836 & U837 + U820 & U821 & U822 == TC528257J-70 or M548263-60J   Video RAM

- TRY REMOVE U251 == 74F04
- TRY INSERT U250 == 74F04 (use fast ic or save U251)
  (crt picture, see my earlier experiences)

- INSERT U2011 == ADG281 == MM9351-VCE

If you can live with error an selftest and are happy with external screen only, leave U2011 & U820 & U821 & U822 open.
As far as I can speak for my own scope, it does not affect the meaurement.


Maybe someone will proof that I got confused while playing around with U250 / U251 for saving the internal screen functional. :-//

induzer :-/O

According to my tests, the ADG281 is not a required component and it is connected to the TLC34075. The TLC34075 is only used to generate the sync signal required by the NuColor LCD shutter. Even if you do not install ADG281, TLC34075, and VRAM associated with TLC34075, the oscilloscope can PASSED self-test
 

Offline zxase258

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Re: Conversion Tektronix TDS500 to TDS700 color oscilloscope
« Reply #12 on: August 20, 2019, 03:02:08 am »
Okay! I've substituted the TC528257J-70 vram chips with TC528267J-60 and it works just fine. The TC528267J-60 chips where half the price on ebay. As for the ASIC I haven't been able to get one yet. The scope powers on in 754 mode with the built in CRT displaying Text on white background with no waveform, and the VGA out displays full color without error.

It does fail the processor self test when run manually but everything else seem to work fine. I guess this might have something to do with the missing ASIC chip. Maybe if someone here has a dead board they are willing to de-solder one of the ASICs and send one my way? Ill buy! Plus beer if your in the DFW area.

I guess I would also need U193. Lots of NOS tlc34075 on ebay from what it looks like!

I should also add that moving U251 to U250 causes the internal display to go out of sync while doing nothing for the VGA output. So for now I'm just going to leave it at U251. The Internal display is white but the VGA output is still in color. LUCKILY! Putting the jumper resistors back to the 540C config allows it to work fine even after adding the addition ram chips!
Please check your oscilloscope ERROR LOG, if there is something like DsyMem, there are some broken bits in the newly installed VRAM. These chips are very likely to be junk, especially if the sellers selling them are located in mainland China or Hong Kong.
I am very sorry that my post was a bit sloppy. I didn't take notes in detail after I worked. It may have some errors, but I can be sure that if the VRAM is not faulty, even if the ASIC is missing, the oscilloscope can pass the self-test.

 


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