I have a Farnell 2ch DTV20 oscilloscope that hasn't been used for years. Now, when powered up all that works is screen grid illumination. No amount of swapping probes and switches has any effect. I can't see any swollen or leaking electrolytics and I've also removed and tested 3 large cap's nearest the transformer and they're ok.

 

Service manual here..

https://elektrotanya.com/farnell_dtv20_2x5mv,20mhz_2x1mv,10mhz_oscilloscope_sm.pdf/download.html

 

Thanks for your help. It was a loose connector ~ must have dislodged it when desoldering the adjacent the power supply capacitor.

Took a couple of minutes for the traces to stabilize but all seems well now.