Panasonic CT-1310M keeps blowing horizontal output transistor

[luRaichu]

Originally Posted by Alex KL-1

Normally, only the charred ones or with extremely bad original soldering due to overheating/thermal cycling. Measure some, and if all measure ok, don't need to continue. (again, is good to remove one leg to eliminate readings from circuit).

Dude, R804 has got to go. It's clearly gone sour and is probably bringing a supply line or component up too high.
Here's my replacement parts list for the important PSU resistors: https://www.digikey.com/en/mylists/list/PTPXQHEAGB ("Notes" column contains part numbers from the schematic)
I also have cap lists. I'll share them later, although I could not find a replacement for the one bipolar 3.3µF @ 160v cap that lives in the H circuit. They just don't make bipolar caps with that kind of voltage tolerance anymore.

[vol.2]

Originally Posted by luRaichu

Dude, R804 has got to go. It's clearly gone sour and is probably bringing a supply line or component up too high.

I think he just meant in general you don't have to test every single resistor. If you test a bunch that look okay, then usually all of them in the same area and/or of the same type will be okay. The main thing to look out for is burned or otherwise darkened areas on the PCB or the resistors themselves. Usually newer resistors (post 1960s or so) don't go bad unless they burn up.

I will add to that, resistors can have corrosion on them like rusted legs that can go inside the package and ruin them, and that's not always visually obvious from the outside. Also, resistors can burn up partially and you won't be able to see it from the outside either.

Just check anything that looks weird and anything close to a heat source like a transistor mounted to a heatsink or smaller resistors that are next to larger power resistors that are meant to get hot

I could not find a replacement for the one bipolar 3.3µF @ 160v cap that lives in the H circuit. They just don't make bipolar caps with that kind of voltage tolerance anymore.

It's possible to create a bipolar cap from two polar caps. Do a google search for the way to do it

[luRaichu]

Originally Posted by vol.2

It's possible to create a bipolar cap from two polar caps.

A bipolar electrolytic capacitor can also be made by connecting two normal electrolytic capacitors in series, anode to anode or cathode to cathode.

What isn't mentioned is that doing it this way should cut the overall capacitance value in half. Some also say it decreases the volt tolerance.
I'm not taking a risk with such a hack.

Originally Posted by vol.2

Do a google search for the way to do it

I use DuckDuckGo and you should too, if you respect your privacy. Which is already dead, I guess.

[vol.2]

Originally Posted by luRaichu

What isn't mentioned is that doing it this way should cut the overall capacitance value in half. Some also say it decreases the volt tolerance.
I'm not taking a risk with such a hack.

You can over provision the voltage handling to avoid any risk, and you up the starting capacitance to reach the target bipolar value. It's also fairly common to parallel a film cap across the electrolytics in order to keep the ESR impedance low.

If you do it right, it's not risky.

Also, you can probably just use a film cap instead and be done with it. There are some places in a set that you might not want a film cap because it will cause ringing or uneven brightness, but most places it's fine

It used to be many years ago that film caps were simply not available in higher capacitances as electrolytics were, and they tended to be more expensive, so they didn't use them. Nowadays, you can get them up into normal value ranges pretty high; although the very high ones are still pretty expensive