Hickock OSC-4 oscilloscope troubleshooting.

[maxhifi]

I've been doing a lot of service work lately, and my oscilloscope has got worse and worse. Basically, keeping it in synch has become extremely critical. I have to mess with the Vernier and sync amp a lot to get it to be stable, and then when the amplitude of the signal changes, it again goes out of synch. I did a quick replacement of all the paper capacitors today, but the electrolytics are still original. Also, I have tried swapping tubes around, and replacing them, to no end.

Of course, I would like to check the waveforms the synch amp is making, but unfortunately this is the only scope I have.

Any help would be appreciated, it's my first time working on the scope.

Ref: https://www.oscilloscopemuseum.com/o...4s40-1437.html