PPI A600.2

[Jason Smith 616]

Does anyone know what would cause these resistors to burn and the amp to power up with only power and ground hooked up ?

 

[Jason Smith 616]

With just power and ground connected here's what i get on the SG3525A

Could the 3525 be defective or any ideas what might cause this ?

Pin 1:2.60
Pin 2:2.59
Pin 3:0.01
Pin 4:0.15
Pin 5:2.07
Pin 6:3.77
Pin 7:2.06
Pin 8:4.92
Pin 9:1..24
Pin 10:0.00
Pin 11:0.98
Pin 12:0.00
Pin 13:12.50
Pin 14:1.00
Pin 15:12.50
Pin 16:5.19

on the gate legs of the power supply fets i get 1.20 volts

This is with no remote applied just power and ground

Any ideas?

 

[Perry Babin]

It appears that the power supply is producing rail voltage. Is that correct?

Confirm that the remote terminal is at 0v.

If so, the 12vsw line probably has a shorted PNP switching transistor. The attached image shows a generic PPI turn-on circuit.