Fender Hot Rod DeVille 'More Drive' Channel Problem

[stereomonostereo]

I've worked on a lot of HR DeVilles, but this is the first i've seen this problem. The amp is working properly, except for when it's switched to the 'More Drive' setting. The indicator light switches off of green, but doesn't go to red. It's not illuminated at all. And neither the drive or volume has any effect on the signal. I've checked the LED itself, and by jumping it with a battery i can get the red the light, so that seems to be working. Has anyone encountered this before?

[Enzo]

SOunds liike a bad LED.

LD1 is a dual LED. Green and red. Green and red together makes yellow. Maybe not in paint, but they do in LEDs.

WHen the drive channel is selected, BOTH LEDs are on to make yellow. Turning OFF the green makes it red for more drive. The relays involved get their coil current THROUGH this LED. Open LED or broken connection to it can render the relay unswitched. If you are seeing green, that means the red side is not working.

The schematic has many test points, in particulr check TP33 and TP36. But I still suspect the LED itself.