hitachi v525 help

[Priestblood]

Hi all
I bought a Hitachi v525 of eBay and I got stung,The problem is running a single channel and the crt is ok but not great  but if I turn 2 channels on at same time the crt goes very dim to the state where you need to turn off lights and squint to see it am new to problem solving I have the schematics but its abit double Dutch .The curser tracker is dim no matter what the settings are.I have tried probing to see any power drops when both channels are on ,also if I increase divisions it dims with each down step
any help would be appreciated    ,haven't got funds to replace not sure to strip and bin if cant fix

Regards

[true]

If in doubt, check voltages

Probably a bad cap or damaged component, there isn't much to these scopes IIRC