Re: TDS 380 won't trigger
It's alive!toggle quoted messageShow quoted text
The parts arrived today.
I replaced the acquisition RAM with a MB8464 - not the original part, but it appears that the original part was unobtainium. The 'scope now displays traces correctly at all sweep rates, and the offset and calibration are again correct.
Thanks again for pointing me to the information on EEblog, and the technical manual.
Sent: Sunday, June 24, 2018 6:32 AM
Subject: Re: [TekScopes] TDS 380 won't trigger
On Sat, 23 Jun 2018 at 20:45 Gary Appel <garyappel@...> wrote:
Thank you Siggi.
At low sweep speed, where the trace rolls across the screen, the 'scope isIf you've tried to run signal path compensation after the acquisition
system wonked out, this could be working as intended. The acquisition
system will have been used to measure the DC offset to compensate, and it
could have measured a large "ghost" offset.
Most of the IC's have a '95 date code. The Dallas chip has a '96 date code.
It is certainly on borrowed time. I have seen a number of references toI'm not sure it's worth the effort to preserve the memory contents of the
NVRAM, as the calibration procedure for this scope looks like a piece of
All you need is some DC and a "fast rise" (<10ns) pulse generator. This is
pretty typical for the CCD-based scopes, it was easy as pie to calibrate my
2430 using what I already had around the lab, plus some spit and bubblegum.
I do have an analog 'scope as well - a 2465A, that is also likely onPiffle - my 2467 has a keeper with an '85 date code in it, and it's still
going strong :). Of course I'm set to calibrate it, should the keeper give
up the ghost, so I'm not too bothered - I'm quite curious to see how long
the battery will last.
It sounds like my first task should be to replace that acquisition memory.Yups, sounds like.
Meanwhile, in my impatience, I just ordered a replacement 'scope. It'sGood luck!