Hi, I have a old Panasonic VP-5720A DSO that power up but keys is locked and CRT display nothing. I have try to disconnect deflections (plus removed "SCOPE" board) and CRT display one big center dot, therefore HV supply is working. I suspect that digital control section is defective, considering inactivity of front panel switches (some lights indicators lights up, always the same, but pressing switches make no changes). Someone has experience in repairing this DSO? Otherwise I can find schematics diagram?
Thanks.
Paolo.