I cannot find any spec's on the GTK device. However the G20N60C3D comes up an an IGBT 600V 45A 164W TO247 case. An IGBT is not a MOSFET but a bit in between a MOSFET and transistor with an emitter, gate and collector. If the servos are identical, the GTK is probably a sub and you'll have to...
It can go either way. Over the years when I was fixing stereo receivers that were hit by lightning, sometimes they were repairable without too much damage. Other times the whole thing was fried ; power supply, amplifier, tuner, etc.
My internet just came back on yesterday after the storm and am catching up on things. If you follow the posts we made, I suggested over 2 weeks ago to use the light bulb to check for excessive current draw and also remove the outputs so they won't blow, check voltages and compare with the good...
I wouldn't use a resistor - just a light bulb in series with the AC line to keep those FET's from blowing. If they blow within 5 seconds when you turn it on without the light bulb, you have a short. Although there are better ways, I would use an ohmmeter to check all the transistor junctions...
Do not remove R470 and R471 and expect the outputs to draw no current. Those transistors are FET's and can stay in full conduction without voltage on the gates to turn them off. You can try the variac to limit the voltage and compare readings with the good side, unless like you say it might need...
Do a google for "schematic diagram for LSG-16 signal generator" and the first match at the top is the owners manual and schematic. Supposedly they're identical.
You can wire an incandescent light bulb in series with the power cord. If it glows brightly when turning on the amp, the amp is drawing a lot of power and still needs troubleshooting. I would use a 100W bulb which would limit current to about 1A (assuming you have 110V). 1A shouldn't blow up the...
It looks like these people have a Numark slide pot but $35.00! https://instrumentalparts.com/numark-spare-parts/all-numark-units-spare-parts/numark-tt-500-tt500-spare-parts/
Years ago I was given a very expensive power amp which had a blown channel and had gone through several repair shops without success. All of the semiconductors tested OK, yet every time you turned it on, the outputs fried. The fix? I replaced every single transistor, bias diode and coupling cap...
Yes they look like part of a current sensing scheme. As the drain on Q445 conducts heavily, it looks like it will turn on Q443 which appears to turn on Q444 also. The output of Q444 is labeled OCP which, I'm guessing might mean Over Current Protection.