GE13PF6504 no picture but green splotches

[JohnCT]

Originally Posted by technoman9

I checked the horizontal output transistor D1453 and found complete continuity (just one ohm) between the base and emitter, but I need to pull it out to see if that's the circuit doing that or not.

It's normal. The emitter and base are across the secondary of the horizontal driver transformer. The secondary is very low ohms. Besides, horiz outputs are pretty much binary go/no go, and since it produces a picture however briefly, you can assume the horizontal output transistor is good.

The green blotches are what RCA used to call "afterglow". This is just stray emissions from the gun that light up the screen because the TV has no HV bleeder to bleed off the HV. That plus some residual voltages at the gun show this.

As others have said, it sounds a lot like a HV shutdown. I used to be a LG ASC and repaired a lot of these. The two most common problems are a bad LV regulator and the B+ bypass capacitor. That cap is connected to the B+ input at the flyback, typically a lower value and higher voltage - 33uf@250 give or take. The regulator might be an "STR" device, either in a TO-3 case or an inline IC although some versions used discrete transistors for regulation. If you can post the pic of the power supply schematic someone will show you what to check.

A way we used to troubleshoot these is to *remove* the horizontal output and put in a 60W incandescent bulb from the collector to the emitter. The regulated B+ should hold steady at the schematic value as the AC is adjusted up and down 10 volts.

If the voltage drifts more than a volt, the regulator is probably shorted. If nothing else, I would change the B+ bridge filter cap and the B+ flyback bypass caps.

John