Old Mitsubishi VS-405R big screen

[gstringe]

Old Mitsi VS-405T rear projection has acquired intermittant vertical
jitter. Hopefully not the IC as it is obsolete. Other than replacing
all caps in the vertical section, anyone remember this old circuit?

many thanks

 

[[email protected]]

Are you sure the yokes are not starting to have insulation breakdown
and short to the ground of the crts?

 

[Tech Data]

What vertical IC? That set uses a two transistor push/pull vertical
circuit. Best bet would be to find the pinout for IC201 and check any
caps or off value resistors around the vertical countdown/ramp pins.

 

[gstringe]

That is of course a possibility but I did a repair of all the yokes
years ago and I think they will hold forever.haha. Actually the jitter
is in all three colors so I would guess that it is a common cause. I
also resoldered a lot of the baord years ago and everything elso looks
great but when it is stable I can get it started by probing components
but I haven't been able to narrow it down to any one yet. I suspect
that I will replace a lot of caps and see what happens.

 

[gstringe]

Yes it does have two transistors as the output but the osc and sync are
part of IC201.
I do have a manual and esr so I will go thru it all but I was hoping
that it might have been a common problem that had a known solution.
Many thanks.