Panasonic PT-53WX53G Flyback HV Lead Removal?

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slr_65's picture
Panasonic PT-53WX53G Flyback HV Lead Removal?

Hi Guys,

I have a Panasonic PT-53WX53G that I'm working on.  It has a high voltage problem - when you turn it on you hear a rapid clicking noise which I think is arcing, the screen turns blue with some fine white vertical lines running through it, and then the unit shuts down and then slowly flashes the front power indicator (it flashes once, pauses, flashes once, pauses, on and on).  All three guns are lighting up but they seem to be flickering.  Reminds me of a flourescent light when the bulbs are bad or the ballast is going out.

I got the unit off CraigsList and it was listed as being professionally diagnosed as a convergence problem and indeed when I opened it up I had a bad convergence resistor.  I replaced the amps and the bad resistor (the others tested and looked ok).  Once I tried to fire it up though I had this high voltage problem.

I hate working on things on the floor so I did disconnected the hv lead from the hv block but I've done that several times before on Sonys and it's the same setup - push in, twist a quarter turn cournter clockwise, let up and it comes right out.  I'm sure it's reinstalled correctly as it's fully seated (I marked the cable with a fine point sharpie where it exited the port on the hv block so I could tell if I had it fully seated when I put it back in) and it wont come out with a firm tug.  The focus block lead is just a round connector that slides over a pin so I'm sure it's installed correctly too.

It sounds likes arcing but I can't see it arcing anywhere when I tried firing it up in a darkened room.  I can't really tell where the noise is coming from either as it seems to be coming from everywhere (and I'm not really getting that close to it!).

I'm really suspecting the high voltage cable that comes out of the flyback transformer.  I can't pull it out of the flyback and it doesn't seem to be the same setup as the hv block as when I push down I don't feel a spring moving, but it can rotate fairly easily in the port.  I'm wondering if something is holding the jacket of the cable in the port but if the center conductor isn't broken?

Does anyone know if this lead can be taken out, and if so how?  Or is it a permanent part of the flyback?  (I can't find a part number for it on the parts list in the service manual).

Looking at the schematic it appears to me that I should be able to do an ohms test between the hv lead and the focus block lead.  Basically it appears to run through the secondary windings, some diodes, and a resistor/capacitor internal to the flyback, if that's the case then I should be able to get a reading one way and not the other (due to the diodes)?

Any thoughts, comments, suggestios would be most welcomed!


Flyback Schematic



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