Re: Tektronix TDS754D - failing acquisition module tests
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jlacerte: that's the exact direction I started heading from a point on. I realized the "short" between pins?2 and 3?of the SRAMs was not a solder?bridge, but something internal to one of the chips. I was actually?measuring a little under 10 ohms between those address buses (A14 and A16).?
I got to this?last night and I have a quick update?on this. I've replaced at this point seven of the eight SRAM chips on that address bus (U201-U208, only U204 is still the original part). This is because once I replaced U203, the low resistance condition between A14 and A16 (a bit less than 10 ohms) ceased occurring. I am pretty confident this was an issue and it was causing part of the errors?(those directly?pointing to "U20X" ICs).? I still have a failed acquisition module.?
I currently have two errors: - ERROR: diagnostic test failure digHFStepDiag
- ERROR: diagnostic?test failure digDataFormatDiag, ERROR!!BYTE mode, in demux 200, i=4... (the rest of it is out of view; can anyone recall how to wrap/unwrap error codes text?).
Ideas welcome. Thank you.? Radu.?
I have a 754D and a 784D.? I really like these scopes except for the display size. I occasionally will hook up a 13" to 15" color display and set on the edge of the bench while I am working.
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If I remember right there are a bunch of mods that can be done with jumpers, caps and recalibration. You can turn a 754D into a 784D.? May try this one day but I have a good working 784D already.? You may want to look into the upgrades once you have gotten all the fixes done to your current scope.
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T. Gerbic
Central California
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