Re: Tek 2467B

Chuck Harris

I am certain that you already know the answer to your question,
but I will answer it never the less...

It is possible that the last time the scope was calibrated was
when it was in pristine condition, and then it went from hand to
hand, and was used like a borrowed mule, until it finally broke
down and had a capacitor failure. In that case, replacing the
capacitors *may* improve the scope back to the condition it was
in back when it was last calibrated. But most likely, it will
need new shoes, and have some burrs in its mane and tail that
need brushing out, a harness in need of a stitch or two...

But what was the condition of the scope when it was last calibrated?
What else has degraded while those capacitors were being used up?
What else has been repaired since the last calibration?
Did the guy doing the last calibration really have his heart in it?

If, and that is a big if, the scope was monitored for its accuracy
and performance regularly throughout its life, and all of its previous
repairs, abuses, whatevers, were logged and could be analyzed, then
you could probably hazard a guess as to what the effect of some
repair you do might be... But who keeps such records? Especially
when they are avoiding doing regular calibrations over long periods
of time?

All we can do is guess. My guess is at any point in time, after most
any repair, calibration would be a good idea.

But as I have said numerous times before I am biased in favor of
calibrations. I look at the world through calibration colored glasses,
because I have the equipment, keep it calibrated, and calibrating these
scopes isn't a big deal to me. It is just 2 to 4 hours of time well

-Chuck Harris

OBTW, scopes have never been a hobby for me. That also colors my view
on calibrations.

tekscopegroup@... wrote:

Here's my optimistic view.

Imagine a scope that has not been calibrated in many years, last time was probably while it still was in its prime, and caps where up to spec, very little power supply ripple (within specs). Now move forward some years (or decades), during which the scope was ever calibrated again. This is probably the case of I would assume most recycled scopes sold on ebay, and I'll bet that its also the period during which the filter caps started to deteriorate. Wouldn't in this case recapping the power supplies, at least in theory, actually bring the scope back more towards correct calibration rather than worsening it? I understand there are many other factors to consider than the power supply caps, as it was pointed out earlier. But just for a minute and for the fun of it, lets consider this scenario only. And again, from a hobbyist perspective only.

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