"Al Schapira" wrote in message
...
On my Tek 465 scope, I notice a peculiar variation of the intensity of
the trace at fast sweep rates. The intensity decreases during the sweep
for about 200 ns near the beginning of the trace and returns to normal
for the remainder of the sweep. It is most noticeable using ALT sweeps.

Please see the pictures at

http://home.att.net/~a.schapira/pix/...cope_.05us.jpg
http://home.att.net/~a.schapira/pix/...scope_.1us.jpg
http://home.att.net/~a.schapira/pix/...scope_.2us.jpg
http://home.att.net/~a.schapira/pix/...scope_.5us.jpg

You can clearly see the intensity drop off for about 200 ns and come
back up. For each picture, the inputs are the same; only the sweep
rate was changed according to the name of the picture file.
Its as if some of the sweep or trigger signal is leaking into the Z axis
circuitry.

If you could suggest a cause (and remedy) for this I would be grateful.
I do not have a service manual or schematic (I would like one), but I am
generally good at troubleshooting and repairs. I just don't have any
experience troubleshooting Tek scopes.

Thanks for any help you can provide with this.

-Al Schapira, KC2HRH,


Something out of kilter in the bright-up/blanking/fly-back suppression
circuitry ?

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
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