Orion XTR 1500.1

[allaroundsound]

what are the odds that a failing gain pot could cause all of this erratic behavior?

[Perry Babin]

It's possible that a bad/intermittent gain pot could cause enough of a pulse to make the amp go into protect.

[allaroundsound]

Interesting. There definitely is something happening at about 1\3 through rotation. However that does not explain the huge voltage spike on the speaker terminals when pressing the subsonic button and/or the Phase

[Perry Babin]

Have you checked the output pins of all of the op-amps to see if any had excessive DC voltage?

[allaroundsound]

might u be able to id the op amp from the pictures on page #1?

[Perry Babin]

They are the 8 pin SMD ICs. They are marked 072. There are 5 on the bottom of the preamp board. It may be difficult to check them. If you want to check them, you may have to remove the board, solder wires on the output pins of the op-amps and then plug them back in. Another option would be to remove the board and find vias that connect to the output pins and check those vias on the other side of the board instead of probing the output pins directly.