Re: 2465B - Weak Readout Intensity


Chuck Harris
 

That means that the trigger hybrid, which does all of the
time and frequency measurements in the "B" model, is having
trouble triggering on the signals you are presenting to it.

You can try removing the hybrid, and putting a drop of
deoxit on each of its terminals, but most times I find that
the hybrid is bad.

On the bright side, all of the 2465 family trigger hybrids
work in all of the models.

One note, hybrids are wicked easy to break. Be sure that
you have rotated, and wiggled, and set the hybrid flat
down on the board with hand pressure as you are spinning
up the nuts. If you don't, it will sometimes catch the
edge of the ceramic substrate, and crack! You are done.

I use a plastic nut starter, like Heathkit used to include
in their kits, to do the initial nut setting, and finger
tightening: Set all of the nuts, head up, star washer down
on your bench where you can reach them one handed. Install
them, and tighten them as much as the plastic nut setter
will, all the while holding the hybrid down with your other
hand.

When you have done that, use a nutdriver to tighten the nuts
an additional 1/8 to 1/4 turn. This is only to keep the nuts
from working loose due to vibration.

The tightness of the nuts has nothing to do with the quality
of the connections to the hybrid!

-Chuck Harris

flanneltuba@... wrote:

I am finally getting this scope to the point of getting ready to do a full, albeit low precision calibration (+/-10% will be fine for my purposes, and within my reference equipment range). I am seeing one issue with the built in Time/Freq Measurement function. Regardless of the purity of the signal I apply, in the case of the picture, a 5 MHz sine wave from a good source, when I select wither T or 1/T Measurement the alert text "CHx: NOISY OR APERIODIC SIGNAL" is show and no time or frequency measurement is given.

I searched the internet and scoured the manual for any reference to this message, but found nothing.

Perhaps one of you might be familiar with this message/symptom. I will note that I have not yet attempted to do a full calibration on this, but most of the readings are well within reason, if measured by the cursors or screen graticules.

( I posted a picture of the screen shot of this, among others, in the Photos directory on the TekScopes@groups.io web page, but don't know how to link to those pictures here.)

Thanks,

- Scott



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