JL Audio 500/1 Rev 11 Brd No -15VDC on Main Brd

[kds9591]

Have a JL Audio 500/1 amp with Rev 11 brd set that does not power-up. Troubleshooting found it has no -15VDC on pin 2 of P4. Traced it back to the main board. Top control brd, connectors are fine. No -15VDC on center 4.7 ohm resistor to the left of T601 on main board.

Any tips or info greatly appreciated.

 

[Perry Babin]

If you have +15 but no -15, the rectifier diode is likely defective since the positive and negative regulated supplies come from the same secondary winding. It could have a bad/open winding but that's less likely.