Hi John,
Best would be to swap the trigger hybrid from one of your
2465 family scopes that does work into the one that doesn't
work, as a test. (as long as you restore the original to the
calibrated scope, there will be no affect on calibration.)
The trigger hybrid is crucial to everything in the parametric
functions.
An additional place to look would be to follow the signal from the
DAC to the trigger hybrid threshold inputs (TLA, TLB). The 4051's
and the TL072's and their associated sample and hold gate parts go
bad sometimes (U2521, U2520, U2420, C2421, C2621).
One repair/calibration blurs into the next. If you think I didn't
repair something correctly, send it back, and I will fix it gratis.
I know I tested the parametric functions on the unit I calibrated.
It is a standard part of the tektronix calibration routines.
-Chuck Harris
John Ferguson via Groups.Io wrote:
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Hi Chuck,
The parametric functions do not work on one of my 2445Bs, the one you didn't
calibrate.? It also doesn't sync on signal on start-up but does work well manually.?
I chased this around? on EVblog a few years back, but never arrived at what to look at.
Is it possible that cleaning up the contacts and gently re-seating a hybrid could
resolve this? Would it make sense to buy a replacement hybrid just in case the
clean-up doesn't produce the desired result?
best regards
john
