7834 horizontal jittery readout

Gordon <tekscopes@...>

Hi All. Just trying to sort out a jittery readout on my 7834. The ramp outputs of the horizontal board look very stable and the trace itself doesn't appear to be jittery, at least nothing like the readout. In inches I'd say it's jittering about 0.040" maybe a bit less but only horizontally. The supplies don't appear to have significant ripple and putting an extra 4.7u on the 130V doesn't make any difference.

Checking TP12 and 13 on the readout board (x and y out) reveals a rather odd waveform http://www.mgcsoft.com/tek/7834_tp12_readout_bd.jpg. The waveforms in the manual aren't really clear enough. Could someone confirm whether or not the waveform is something like normal please.



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