Type 453A No HV


kc4bga
 

Hi everybody! I have a 453A with no HV. I actually have2. One's for
parts. Anyway it did work but the HV would suddenly climb way up, it
would crackle and then the trace would start flickering until I
powered it off and then on again. It done this after warming up
about 15 to 20 minutes but not every time. If it was in a cool
enviroment it didn't always do it. Thinking it was the Regulator
section I tried freeze spray on the Z axis board with NO luck. Then
one day NO trace at all. I have since swapping Z axis boards and HV
modules with still no luck. Even new transistors...checked
everything. All voltages are in spec except around the HV trans area
and feedback area. I have only 1 HV transformer since that was the
reason I bought the 2nd one for parts.

Any answers or advice anyone on this one. I think it's the HV
transformer again. Am I right?

Thanks in advance.

Patrick