Tektronix TDS 540 repair

[feedback.loop]

Hi!
I am trying to repair Tektronix TDS 540 (with no A).
Mostly successful, but cannot figure out the last(?) problem:
Fully recapped and cleaned the boards in the process.
Desoldered DS1245Y-120 NVRAM, backed up in a programmer, soldered a socket, put the NVRAM into the socket.
Now it shows only one error: "FAIL ++ Processor", but seems to work fine. Passes SPC and other tests.
Seems to show all waveforms just fine. I don't see any problem with that.
After clearing the error log (using a GPIB command) and rebooting, two lines show up in the error log:
SEVERE INTERNAL ERROR diagnostic test failure pu_diag sequence
SEVERE INTERNAL ERROR diagnostic test failure extended cal librarian reset

I don't think this model has a calibration EEPROM on the acquisition board. Everything must be in the NVRAM. Is it possible that nothing is wrong with the hardware, and this is just a matter of clearing some error condition in the NVRAM?
Does anyone have a working dump of the NVRAM for this model? Firmware v1.10e
I would appreciate any help very much.

[Tantratron]

I've never seen so far any no suffix or A or B serie for these TDSxxx, I just know C series and D series.

Since it is takes little time, maybe open your TDS cabinet then remove the Acquisition board to verify if there is or there is not the two small EEPROMs.

As for you NVRAM dump, did you save their content prior desoldering and did you have already that Fail ++Processor ?

[feedback.loop]

I don't see any EEPROMs.
The error was there from the start together with a few more that went away after recapping and cleaning.

[wn1fju]

If it is anything like the 2-channel TDS520 I recently repaired, the cal constants are stored on the "firmface" board, the board that sticks down vertically
between the front panel board and the processor board.

You should be able to find the NVRAM binary at   http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=01_ROM_Images_and_Drivers
Enter TDS540 in the search box at the top of the listing.

I guess I was lucky with mine - after the recap, everything worked fine with no errors and calibrated nicely.

You can also search around in the various Tek forums and will find a cute way to alter a couple of bytes in the NVRAM to enable the FFT processing.

[wn1fju]

Here's the link to that forum entry on enabling the FFT:

https://forum.tek.com/viewtopic.php?t=136932

Worked fine on my TDS520, although the splash screen at startup says nothing about the options now being enabled.  Yet, all the FFT menus are now present and everything works.

[CaptDon]

I went through the CAL screen and did 'Run All Tests'. It finally cleared the problem.
Sadly your NVRAM went partially braindead before you backed it up. The data in the
chip WILL BE SCRAMBLED after de-soldering!!! You cannot use the data in a 20 year
old de-soldered chip as backup!! You need a clean copy of the data (available here
on the forum from members) and reprogram your replacement chip. Hopefully you
bought the re-designed replacement and not the bogus Chinese garbage!!!

[feedback.loop]

If it is anything like the 2-channel TDS520 I recently repaired, the cal constants are stored on the "firmface" board, the board that sticks down vertically
between the front panel board and the processor board.

You should be able to find the NVRAM binary at   http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=01_ROM_Images_and_Drivers
Enter TDS540 in the search box at the top of the listing.

Yes, there is a separate board with flash chips, but I don't see EEPROMs there.

Indeed I found a couple of NVRAM dumps, but for firmware 2.16e. I am not sure if it is compatible with my firmware 1.10e, and if it would make sense for me to upgrade my firmware at this point. It probably will require calibration. And I am not sure how to do it and if it is compatible with my hardware.

Thanks for your help.

[madao]

Have you  NI & Agilent-GPIB -Stuff and  Windows PC ?

 If yes, you can dump  old firmware and give me. I check it on my  TDS540 (2.16e) if  it runs fine with  old firmware,  you can upgrade it to newest firmware. 

unified tektool  (download of tool is at bottom of  frist theard)
unified tektool

greetings
matt

[feedback.loop]

I have Agilent USB GPIB adapter. As I understand, it won't not work with this software.

Have you  NI & Agilent-GPIB -Stuff and  Windows PC ?

 If yes, you can dump  old firmware and give me. I check it on my  TDS540 (2.16e) if  it runs fine with  old firmware,  you can upgrade it to newest firmware. 

unified tektool  (download of tool is at bottom of  frist theard)
unified tektool

greetings
matt

[Tantratron]

I have Agilent USB GPIB adapter. As I understand, it won't not work with this software.

Myself have been using a Macintosh connected to the NI interface, it worked fine after I've compiled these tektools and tekfwtools, see for the @ragge excellent repository https://github.com/ragges/tektools

Check but as far as I know, @ragge used an Agilent interface but you might see with @madao who improved the self-detection memory type for older TDSxxx as yours.

I do no have an Agilent to test for you but it should work easy if you know how to compile C code then launch a terminal shell

[madao]

I have Agilent USB GPIB adapter. As I understand, it won't not work with this software.

Have you  NI & Agilent-GPIB -Stuff and  Windows PC ?

 If yes, you can dump  old firmware and give me. I check it on my  TDS540 (2.16e) if  it runs fine with  old firmware,  you can upgrade it to newest firmware. 

unified tektool  (download of tool is at bottom of  frist theard)
unified tektool

greetings
matt

It is possible, it works with Agilent, probably: You must enabled NI VISA in your agilent GPIB software. But, i didn't know about it, because i have only NI-GPIB stuff.
One member has checking my unified tektool with agilent  USB.-GPIB adapter and it runs good (and slow, normal by USB-GPIB)