I have a Tenma model 72-300 oscilloscope with no trace or sometimes a pinpoint trace. Capacitor C308 heats up with unit turned on. I removed capacitor and it test out fine on my short/open tester. It's a .01uf 1500wvdc cap. It measures 22nf on my meter which is a little high ( .01uf=10nf). It's part of the CRT circuit so I suspect something is loading the circuit causing the cap to overheat. Any thoughts?

 

Please post the service manual here. Saying that cap C308 heats up tells us nothing without the schematic.