I purchased a used Audiobahn A16000V amp off Ebay some time ago. It was worked great till this morning. It's used to drive a RE SX12, 2-ohm mono load.
Like all Audiobahn amps, the thing gets smoking hot at it's lowest rated impedance when playing for 30+ minutes.
I didn't think much of it, as my other amp (Audiobahn A8002) will just shut off for awhile when it gets too hot and power back up on it's own.
Well this morning was the first time the A16000V went into protection, which I knew it would eventually because I have an hour drive with the music up. Problem is, it didn't come out of protection.
Now that it's later on in the day, it's had sufficient time to cool down. The amp powers up, but the protection light still stays red.
What gives? Is there something I need to do to reset the amp? Fuses and connections are all fine. Please help.
Update-- I let some of the smoke out of the amp today. With the amp in protection, I removed the RCA cables which sent smoke out the sides of the amp. Please help me fix this thing.
Being quite handy with electronics, I ripped the amp apart to see what happened.
A) The power transistors look good. No scorching or burning of any kind and secured solidly to the aluminum frame for heat dissipation. Thermal interface material used throughout.
B) Two wire wound resistors are fried. By the looks of things, there is one resistor per output transistor. This amp uses six 8A PNP and NPN output transistors.
I'll try to explain the layout of the PCB. The power MOSFETs are on the left, 6 on top, 6 on bottom. There's two transistors on each side of the center of the board, but I'm not sure their purpose.
The output transistors are on the right side of the PCB, 6 NPN type on top, and 6 PNP type on bottom. There is one wire wound resistor near each output transistor. Two of the wire wound resistors are fried for some reason. If X is an output transistor, and R is a working wirewound resistor, the blank spot is the fried one as located on the circuit board:
XXXXXX RRRR R RRRR R XXXXXX
What would cause the fried resistors? The amp was working fine until it went into overheat protection. The rest of the circuit board and components look flawless.
Anyone with electronics knowledge chime in. If there's anything further I can test, let me know. Comments / ideas / suggestions would be greatly appreciated.