Search found 31 matches

by fenugrec
January 18th, 2018, 8:06 pm
Forum: Other or Discontinued Oscilloscopes
Topic: Tek 455 scope issue - low +95V
Replies: 2
Views: 16

Re: Tek 455 scope issue - low +95V

Not familiar with that scope, sorry. Just some ideas: - if the 95V is produced from a voltage doubler, suspect the diodes + caps there. Caps especially... - if the 95V is just rectified + filtered from an AC winding, and indeed something abnormal is loading it down to 70V, then you should see huge r...
by fenugrec
January 16th, 2018, 7:28 pm
Forum: Other or Discontinued Oscilloscopes
Topic: TDS540 Blank Screen
Replies: 9
Views: 418

Re: TDS540 Blank Screen

charlyd wrote:
January 16th, 2018, 2:12 pm
any suggestions where to get the dsyDiagVscDiagReg diagnostic
To quote myself,
Have you tried entering dsyDiagVscDiagReg on the service console port ?
I'll repeat again, have you even tried the service console port?
by fenugrec
January 9th, 2018, 7:24 pm
Forum: Other or Discontinued Oscilloscopes
Topic: Need error info to repair donated Maker Space TDS540A scope
Replies: 18
Views: 1377

Re: Need error info to repair donated Maker Space TDS540A scope

shot in the dark - make sure you have RTS/DTS flow control still enabled
by fenugrec
January 9th, 2018, 7:12 pm
Forum: Other or Discontinued Oscilloscopes
Topic: TDS540 Blank Screen
Replies: 9
Views: 418

Re: TDS540 Blank Screen

The KEMET (T583D336K016AHE060) polymer for space applications [...]Fun with optimal replacements and potential improvements. I think that's a a mostly a waste of time and effort - they certainly didn't spec the absolute lowest ESR types available in the mid-90s when these were new. I'd say just ins...
by fenugrec
January 6th, 2018, 11:48 am
Forum: Other or Discontinued Oscilloscopes
Topic: Need error info to repair donated Maker Space TDS540A scope
Replies: 18
Views: 1377

Re: Need error info to repair donated Maker Space TDS540A scope

Got the console board built and managed to get the log which helped me solve the problem Nice. What was the fix ? It looks like we'll need a GPIB card, etc to use TekTool. We don't have that. I'll look into copying the NVRAM with a programmer; I have copied NVRAM that way before but never for a Tek...
by fenugrec
January 1st, 2018, 7:40 am
Forum: Other or Discontinued Oscilloscopes
Topic: TDS7xx cal software with other ISA cards
Replies: 0
Views: 144

TDS7xx cal software with other ISA cards

Hi all It's a well-known fact that the Field adjustment software for the TDS6xx/7xx scopes is very fussy about the ISA-GPIB interface they need in order to work. But luckily there's more than one alternative. I've listed them in a post on eevblog which I won't duplicate here . The most groundbreakin...
by fenugrec
December 31st, 2017, 12:24 pm
Forum: Other or Discontinued Oscilloscopes
Topic: TDS600B Waveform Processing Flow?
Replies: 12
Views: 2476

Re: TDS600B Waveform Processing Flow?

hexley ball wrote:
December 29th, 2017, 1:36 pm
The waveform issues noted in my original post in this thread have been resolved.
Awesome ! Well done.
Would you mind sharing details on your homebuilt replacement NVRAM ? If you need somewhere to host drawings / notes / schematics, I could place them on my github repo.
by fenugrec
December 10th, 2017, 6:50 am
Forum: Other or Discontinued Oscilloscopes
Topic: 2430A HV PSU variants
Replies: 4
Views: 889

Re: 2430A HV PSU variants

I think my U227 chip is faulty at the moment. I have followed the manual for the fault-finding of "no-intensity control" Does the schematic give any clue as to what it is / does ? It could be just an opamp... I assume you've tried searching the net wit the tek IC #, but if you're lucky other parts ...
by fenugrec
November 27th, 2017, 5:00 pm
Forum: Other or Discontinued Oscilloscopes
Topic: TDS600B Waveform Processing Flow?
Replies: 12
Views: 2476

Re: TDS600B Waveform Processing Flow?

I looked at the analog signals going **in** to the ADCs, and those look OK. Ah yes, I misunderstood. I'm not sure how you figure the ADCs run at 8MHz though ? They'd have to be a few hundred MSPs each ( I forget the exact specs on the 644B)... Nice job on the clock summary, it's always nice to have...
by fenugrec
November 24th, 2017, 6:20 pm
Forum: Other or Discontinued Oscilloscopes
Topic: TDS600B Waveform Processing Flow?
Replies: 12
Views: 2476

Re: TDS600B Waveform Processing Flow?

Hmm. I'm curious, how did you go about checking the ADC data outputs ? If your LA is fast enough, can you watch the data bus from the mux ICs to the memory banks to try to see the glitches ? They would probably also appear on the D1 bus thru the ~100pin connector but there may be a lot of other stuf...
by fenugrec
November 24th, 2017, 4:16 pm
Forum: Other or Discontinued Oscilloscopes
Topic: TDS600B Waveform Processing Flow?
Replies: 12
Views: 2476

Re: TDS600B Waveform Processing Flow?

Hi, did you disable ET on those tests ? Also, if you go to max acq length (not sure if you have the 1M/2M options?), do the spikes appear everywhere, or with any kind of pattern ? Hopefully trying to see if it can be isolated to a part of the address space of the sample memory. I think there's suppo...
by fenugrec
November 23rd, 2017, 5:47 pm
Forum: Other or Discontinued Oscilloscopes
Topic: TDS754D Processor Fail after Dallas swop
Replies: 4
Views: 2111

Re: TDS754D Processor Fail after Dallas swop

@charlyd: have you tried clearing the error log (over GPIB or the service port) *after* swapping the NVRAM ICs ? I doubt your problem is caused by the X24C02 chips. @strick : interesting comments re DC accuracy. One option I'm contemplating is an eval kit for an 20-bit DAC by Analog: http://www.anal...
by fenugrec
November 23rd, 2017, 5:33 pm
Forum: Other or Discontinued Oscilloscopes
Topic: How to decipher error logs TDS544A
Replies: 4
Views: 2808

Re: How to decipher error logs TDS544A

minor addition - it is also possible to clear the error log from the internal "service console" port, if GPIB is not an option. IIRC the command is "scopeErrorLogClear"
by fenugrec
November 23rd, 2017, 5:22 pm
Forum: Other or Discontinued Oscilloscopes
Topic: TDS 540B not responding to CATS Initialize DUT
Replies: 9
Views: 10248

Re: TDS 540B not responding to CATS Initialize DUT

Disclaimer : I own a TDS744A, but haven't calibrated it or any of these scopes (yet). What I have done is spent time reverse engineering the adjustment software. The PC2A card uses an unusual series of ports, all with the same lower 10 bits "0x2E1". The upper bits are selected by the jumper switches...
by fenugrec
November 23rd, 2017, 5:02 pm
Forum: Other or Discontinued Oscilloscopes
Topic: TDS600B Waveform Processing Flow?
Replies: 12
Views: 2476

Re: TDS600B Waveform Processing Flow?

I don't have much to add in hard facts on the signal flow, but I would guess the issue is somewhere before the sample data makes it to the CPU board. If you haven't already, I'd suggest testing all kinds of permutations of single/multiple channel, varied acquisition depth, samplerate, with / without...
by fenugrec
November 23rd, 2017, 4:51 pm
Forum: Other or Discontinued Oscilloscopes
Topic: TDS460 Power supply fixes
Replies: 1
Views: 861

Re: TDS460 Power supply fixes

Thanks for sharing ! your troubleshooting is probably applicable to other TDS scopes of that generation too.
by fenugrec
November 23rd, 2017, 4:41 pm
Forum: Other or Discontinued Oscilloscopes
Topic: Please help!! Tek 2445 not working
Replies: 1
Views: 865

Re: Please help!! Tek 2445 not working

"is it worth the repair" depends on value to you, vs replacement / resale value, and how much you value your time. For a small time investment you could at least pop the case open and do a good visual check - how dirty is it, evidence of cap leakage / burnt parts, quick check of DC supplies... if th...
by fenugrec
March 21st, 2017, 4:27 pm
Forum: Other or Discontinued Oscilloscopes
Topic: tds540 repair
Replies: 20
Views: 24938

Re: tds540 repair

and would like to monitor the console port as you do. Could you let me know how to set it up, both physically (connection points) and software related (bauds and such)? See these https://forum.tek.com/viewtopic.php?t=138100 https://forum.tek.com/viewtopic.php?f=568&t=138489&p=280292 https://forum.t...
by fenugrec
March 21st, 2017, 4:17 pm
Forum: Other or Discontinued Oscilloscopes
Topic: TDS-524A NVRAM backup
Replies: 31
Views: 25207

Re: TDS-524A NVRAM backup

I built one of the serial debug connections using the option 13 card and use it for monitoring power on self tests and SPC. Gives a lot more info than the simple diagnostics for finding and fixing problems. However, I've never tried to use it to give commands. Funny you should mention this now, I s...
by fenugrec
February 6th, 2017, 1:59 pm
Forum: Other or Discontinued Oscilloscopes
Topic: TDS 744A strange 2GS/s behavior
Replies: 11
Views: 11438

Re: TDS 744A strange 2GS/s behavior

I finally opened the case and did a lot of visual inspection inside, as well as some probing. - front panel , and A10 processor board : SMD electrolytic caps have been replaced at some point by radial caps. I could find no trace of leakage or corrosion on the boards so it was probably done as preven...

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