Re: 7904 excessive shadow/flare

Roger Evans
 

To my eye each of the shadow peaks and troughs of the sine wave lies on a straight line joining the real peak/trough to the CRT centre, but farther out. This should be very obvious at say 100msec/div. I would guess the probable cause is the CRT cathode voltage dropping out of regulation due to a HV capacitor failure. If you don't have a HV probe you should be able to see the ripple on the feedback to the regulator.

Regards,

Roger

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