Preset Management LED Not Working

[who]

Pressing the Preset Management button results in the appropriate menu being displayed.  However, the LED does not light up.  As you may know from my other thread, I replaced the ribbon cable between the main chassis and the front panel and successfully tested continuity for each of the 60 pins.  Here's what I've done since:

1. Reflowed the connection of the LED connector soldered to the front panel PCB
2. Replaced the LED with a new LED

Any ideas what might be wrong?  Thank in advance!

[AvD]

Hello,

As my EIII is open and the leds are working I tested the LED module:

Quick test on PCB solders.
If the module is switched off (led off) all 4 pins have a 0V current.
Switched on, I can read 1.74V DC on pin 2 and 4 (neutral on pin 1 - 1st at left).
Note that my PS is calibrated at 5V.

If you have the same reading when ON, the led should probably light up if the new led is of a correct specs and seated in the right direction.
If you changed the led itself but not its socket I would try comparing the voltage at PCB with what's going out of the socket.
problem may be oxydation/bad contact within the socket.

If the PCB reading is not the same, I would search for an oxydation on the PCB tracks as this one is more exposed to moisture.

Otherwise if your 60pin ribbon is OK, the schematics indicate that leds are driven from the main CPU but that would be a different story.

Hope this helps.