Re: Continuing Problems with 7704A Display


n4buq
 

Hi Albert,

I was hoping this might just be a calibration issue. No telling who has been fiddling around with those controls before I got it. I'll have to investigate that.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Albert Otten" <aodiversen@concepts.nl>
To: "tekscopes" <TekScopes@groups.io>
Sent: Saturday, October 9, 2021 12:17:19 PM
Subject: Re: [TekScopes] Continuing Problems with 7704A Display
On Sat, Oct 9, 2021 at 05:10 PM, n4buq wrote:


4. If the vertical values for the trace cause it to swing to the top and
bottom (and beyond) part of the screen, the readout characters will move
vertically in sync with the + and - swings of the trace. Even stranger, if the
input is a sine-wave, the individual readout characters will bounce up and
down but out-of-sync with each other (e.g. the first character will appear
low, the second character will display about 0.2 division higher, the third
character will be at the same height as the first, etc.). This is one of the
oddest things I've seen.
Hi Barry,
This is "normal behavior" when the vertical amplifier LF response is not
properly adjusted. The dot jump from trace to readout position has undershoot
or overshoot. Similar for horizontal amplifier and position.
Albert


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