Great, my VT52 is shot.

Chris Zach cz at
Sun Apr 19 17:09:38 CDT 2020

> As I wrote earlier in the thread I think it is a good idea to check the V
> sync and H sync signals to check that they are right in pulse length and
> shape.

Good starting point. From the schematics would that be scope probe to J1 
pin 5 for horizontal and j1 pin 9 for vertical? Also which is J1, and 
how are they numbered :-) Also is there a good ground reference point?

Also is there a document that links the part numbers on the boards with 
what's on the schematics?

> There are indeed electrolytic capacitors in the vertical deflection circuit
> but I am not sure if that would make the beam move much faster since for a
> faster move of the beam also requires a higher voltage over the deflection
> coil to create a faster ramp up of the current trough it. But it is
> definitely worth checking. Especially since the scan lines are sloping a
> bit and not straight as one would expect.

I would believe a capacitor failure due to heat, any ones in particular 
I should check?

> So do I. And now we need Chris to do some measurements on it to get further.

More than happy, just haven't worked on TV sets before and would rather 
not blow off my hand. I'm guessing the really dangerous voltage is the 
one on the bottom left that comes off the step up transformer over to 
the odd plug going into the VT52 rear bulkhead (HV to display)


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