Tek CSA7404/TDS7000 repair project (Upgraded memory/CPU)

[colorburst]

I'm not familiar with the actual board or the trigger chips, so can't help you there unfortunately.

However, my opinion is that with the acquisition hardware from a TDS7254, your scope is effectively a mislabeled TDS7254. I'd see about fully converting it to a 7254 instead.

Lower BW models tend to have extraneous filters in the signal path and sometimes skip steps in the factory cal. ASIC grades might be different. It can be a very involved modification with many unknowns.

[calibrationfixture]

Hi,

Contrary to the TDS5000B and Non-B Series and the later DPO, DSA and MSO Series there is, as far as I know, no Memory Erasure and Nonvolatile Parts List for the CSA/TDS7000 Series. Later Documents are labeled Declassification and Security. There is a 077-0524-00 Declassification and Security Document which should list these Parts for the earlier TDS6000 and CSA/TDS7000 Series, but concentrates mainly on the TDS6154C.

Calibrationfixture

[charlyd]

for those who are struggling to get there ACQ in line with the unit model. Here is what to do.
in the corner is a bridge array where selection can be made.
This can be done  by planning a zero Ohm resistor over the right pads.  for selection TDS7404  only a R1069 is "0" ohm (bridged)

for tds7254  R1069 and R1062 need to be bridged. so in my case removing R1062  got my board shownieuws as a TDS7404.  and in that family the units 7104,7254,7404  have the same boards apart from the generation number.

[coromonadalix]

@charlyd

thats for the non B models  right ?

thats the question you asked earlier,  how did you find out 

[charlyd]

hi yes this is for the none B  version.
i found out by compare the board with two other 7404 boards i have laying arround.
and these sort of bridge rows are mostly meant for these adjustments.
After removing R1062  (0 ohm)  reinstalling the board and booting up, the board messaged like 7404 and the option key was pickup straight away.

[charlyd]

and for my trigger chips. they seems to be dead. dropping this message...
even thought all diagnostics test are pass

[coromonadalix]

sad for you  and getting these .....   

In the 7404 i restarted, theses chips dont have any hs on them,  and they seem good for now, no discoloration

all tests passed and all channels where fine with a 3.2Ghz  sig generator


i may re-play in it  ...  since we may buy an sds7000a scope soon, the 7404 was a plan B  loll

still had an crazy idea to put an intel 815 in it ... very very tight fit,  but seems to miss a voltage to start ??

[charlyd]

a Quick advise:  add heatsinks better yesterday,... then tomorrow, i did some measurement with the flir, chips temps are way too high, without heatsinks they will die eventually.
but i type this  message over and over here....