If this is an SMPS it should never be really hot. The only things that can cause that are an overload or not enough drive.

If you really can't get a print you have to ear reverse engineering. To know the output terminals, now get to know the input terminals.

Figure out if it has a shunt resistor and/or a series resistor, and determine where that is coming from. You figure out what kind of drive it needs and you figure out the device. Then you can work on a replacement.

Termy secret 25. Take about a hundred watt audio amp, hook u a generator and feed it with like 3KHz. Almost anything will work. But crank it out ad see if you get the voltages on the other end.

The reason I say to do this live test, even if it is a bit of a bitch to do it is because if it is not bipolar drive problems are rare.

Before SMPSes came into vogue I used to use a variac. Just feed ANY winding of that transformer and see what happens. I think you are going to find something shorted. HA, if you got a good enough amp you can make the smoke come out and find the bad part quick.

I made a good life out of fixing what others could not. Now you don't have to buy a function generator, if you got a smartphone there is a app for that. You get a plug, plug it into a stereo with respectable power, and you got yourself a dandy piece of test equipment there.

if you need a 100 WPC amp I can sell you one for fifty bucks, but what it costs to ship might be out of this world. You got Craigslist where you are ? Deal locally in cash. Best way. Paranoid ? Get a gun.

Actually for the best bang for the buck get a Crow. Audiophiles don't seem to like them so they are not that expensive and you ru them into a short circuit they do not fry. They might trip a circuit breaker at your electric panel but they will be fine.

I have more advanced methods, but no time to type them out Just try that. THEN we talk about the transistors, I will need to know just how they are driven and you will have to run it and have it at east try to start to see what it puts on those gates or bases or whatever they have. That will tell us.. Then we got it. All we have to do is accommodate it...