Hey guys! I'm not new here, I've been a long time stalker, but now I definitely need help.

[cush man]

I've seen a thread on here before about this same MCD360 Clarion Xover, that has a notoriously prone to failure power supply.

I was wondering if you guys can help me find a solution.

 

[rayma]

Needs a schematic.

 

[cush man]

This was all I could find.

 

[steveu]

Looks like they paralleled two BJT transistors without separate emitter resistors, which is kinda stupid. Each transistor needs a separate emitter resistor (R1a R1b and R2a R2b). Alternately larger transistors instead of a pairs. Also note that 2SC9013 is only rated 20V and a P-P transformer drivers need to be at least 2x VCC, ie you need higher voltage transistors, more stupid? I might suggest a pair of BD135 ... 139.
But the real cause may be something drawing too much current, ie diodes or a chip.

 

[cush man]

Looks like they paralleled two BJT transistors without separate emitter resistors, which is kinda stupid. Each transistor needs a separate emitter resistor (R1a R1b and R2a R2b). Alternately larger transistors instead of a pairs. Also note that 2SC9013 is only rated 20V and a P-P transformer drivers need to be at least 2x VCC, ie you need higher voltage transistors, more stupid? I might suggest a pair of BD135 ... 139.
But the real cause may be something drawing too much current, ie diodes or a chip.

Thank you, do you think an op-amp is drawing too much current? Or maybe the TL 494 is bad, but I checked it. And it's outputting the PWM 4 volt drive for the transistors.

I only have a pair of C1318 on hand, will they do? I also have to do some leg crossing.

 

[cush man]

Looks like they paralleled two BJT transistors without separate emitter resistors, which is kinda stupid. Each transistor needs a separate emitter resistor (R1a R1b and R2a R2b). Alternately larger transistors instead of a pairs. Also note that 2SC9013 is only rated 20V and a P-P transformer drivers need to be at least 2x VCC, ie you need higher voltage transistors, more stupid? I might suggest a pair of BD135 ... 139.
But the real cause may be something drawing too much current, ie diodes or a chip.

I had these MOSFETS, so I used them. I also placed 2 1k ohms resistors from pins 9/10 to pin 7 for the pulldown circuit. I used 2 100 Ohms resistors for the gate drive, but for some reason I'm only getting 1.5 volts on the gate drive. Also the oscillating frequency is over 100K.

 

[Perry Babin]

The FET solution is typically the best. More work but it will never fail. I typically used a clamp with a button head screw so the crossovers (mostly Coustic crossovers) would sit flat.

The high frequency is due to the small core. Small cores require a combination of higher frequencies and more turns.