Boss CE-1 chorus/vibrato LED not working

[pontiacpete]

The LED not working is the Normal/Effect, the other works fine. The LED lights up when on the diode checker of my meter. The switch is good, tried another in its place. I re-soldered the area of ‘22’. Q8 and Q9 aren’t shorted and resistors off them are good boss_ce1-chorus.pdf Does anyone what this problem could be? I wonder what the little arrow at ‘21’ is suppose to connect to.

[Jazz P Bass]

Are you working on D101?
That is driven by Q14.
21 looks like 'circuit ground'.

https://archive.org/details/manualli...p?view=theater

[Helmholtz]

"21" looks like -14V supply to me.

[g1]

edit: I thought this was a regular boss stomp pedal that ran off battery, but I see it is not.

Your schematic is for an ET-10 unit, is that the same as the CE-1 ?

[g1]

I see elsewhere that 'ET-10' is printed on the CE-1 circuit board.
In case there is any difference, here is what seems to be a slightly later (D) version of the schematic:

[Helmholtz]

Back to the facts.
What voltage do you measure at point 21?
This voltage supplies both D101 and D102.
Do I understand correctly that it is D102 and not D101 which doesn't work?
Does the unit work otherwise?

[pontiacpete]

-12vdc at 21. It’s D102 that’s not working

[Helmholtz]

-12vdc at 21. It’s D102 that’s not working

That might be just a bit too low (i.e. not negative enough).
Are you getting the +/- 13V supply voltages?

[pontiacpete]

On the anode of D102 there’s-14

[Helmholtz]

On the anode of D102 there’s-14

So you have -14V at point at point 22 and -12V at point 21?

[pontiacpete]

Yes that’s it. The effect is working, don’t know if I said that already. Anyway I have gig to head to

[Helmholtz]

So the LED is reverse biased and can't light.
Actually it's not plausible that point 22 would be more negative than point 21.

[pontiacpete]

It wouldn’t surprise me if I’m interpreting my readings in reverse. I’ll check that

[Helmholtz]

Make sure the cathodes of D101 and D102 are connected.
If D102 doesn't light, try a new one (might have drifted somehow).

[Helmholtz]

You could also try swapping D101 and D102 for a test.