Punch 500X part ID

[mbates14]

I need the part numbers/IDs for D3, R27, R41.

these are completely black/blown up and burned to smithereens.

 

[Perry Babin]

I sent you a 500x schematic but I don't know if it's right. R27 could not have burned. There isn't enough voltage in the amp to burn it.

 

[mbates14]

ok D3 and R41 look like they provide a false ground for the +/-15v regs, is that right?

What would cause it to totally burn up?

 

[Perry Babin]

The diodes commonly fail when someone allows a 12v line to contact the RCA shields. The resistor burns after the diode opens.

The ground for part of the preamp section is floating. This is done to prevent noise from a ground loop. The diode and resistor prevent the ground from floating too far from chassis ground when nothing is plugged into the RCAs or when a signal source with an ungrounded shield (MP3 players) is used.