msg wrote:

Greetings:

I just acquired a Tek 7603 scope with 7A18 dual-trace vert. and 7B53A
timebase plugins...
snip

The display is very corrupted: odd blanking and sawtooth displays
appear with no vertical input and horizontal sweep width changes with
timebase selection in a drastic way. A vertical input signal modulates
the strange displays in a fashion that suggests the vertical section
is functional and the vertical position controls do work.

The problem was a defective C811 (14000 uf / 25v), the -18V filter
capacitor for the -15V supply.

Scope works well now.

Regards,

Michael