Side LEDs stay on when dimmer is off

[rv_bass]

I have a series bass with side LED markers controlled by a dimmer switch.  Today I found that half the lights stay dimly lit when the dimmer switch is rolled all the way off.  Has anyone encountered this before?  If so, do you know what is causing this to happen and is there an easy fix to resolve the issue?  Thanks.

Rob

[rv_bass]

Hmm...now the LED on the 21st fret doesn't work at all.  I checked all of the connections in the electronics cavity and the wire under the neck pickup, and everything looks good. It would be nice to get the LEDs to work properly again, and they are only about a year old so I'm not sure what could be causing the malfunction.  If anyone has any suggestions on how to start trouble shooting this I would appreicate it.  Thanks.

[jazzyvee]

I have a dimmer knob on my series II and it does not have an off setting. At the lowest level it is still usefully bright. On the hightest setting I can feel the warmth from the led on my thumb if I grip round the neck but they are all evenly lit. If one is not working I doubt if there is anything you can do from the cavity to fix it as there are only the trailing leads in the cavity. Might need a trip back to base. But maybe someone else has an idea.

[rv_bass]

Thanks, Jazzyvee, I'll call Alembic and see what they think my options might be.

[rv_bass]

Now that I think about it, the malfunctioning of the LEDs coincided with the fret ends extending over the edge of both sides of the finger board.  My hypothesis is that contraction of the fret board wood with dry winter climate pinched the LED connections in the routed out section of the fret board, causing the LED malfunction.  The null would be that fret board contraction has no effect on LED function.  I put a Herco humidifier in the case to see if the fret board absorbs some of the moisture and expands, and if so if that has any consequence on the functioning of the LEDs.  The humid northeast summers will add considerable humidity to the ambient environment, so I will see if the wood and LEDs react then as well.  If nothing else it's interesting to ponder.

[mica]

It actually depends on how the LEDs were installed.

Early dimmer controls didn't dim all the way. THe lights don't all come on at the same voltage, so dimming fulling will make some drop off sooner than others. If there is a switch too, then the dimmer doesn't ever go down to zero, we leave that job for the switch.

This is especially important for instruments that are battery only - if the dimmer was down all the way, but a tiny glow was still going on, then the batteries would drain down without you knowing.

What year is your bass?

[rv_bass]

Mica,
Thanks for the reply and info.  It's a 2015 bass with dimmer only.  I can call you to talk further.
Thanks,
Rob

[rv_bass]

Just an update...I found that the source of the issue is likely the small circuit board associated with the dimmer switch.  It appears that each LED has a wire that is attached to this board, and connection of the wires might be compromised slightly. The board is wrapped in fiber tape, when I compressed the tape around the soldered wire connections, the dimmer lights up all of the LEDs (formerly about three or four LEDs did not light up).  So, I think I'm on the right track with the trouble shooting.