Fixing a Boss DM 2 led check light

[soma89]

Hey there,
Just replaced the led of an old l boss dm2 analog delay and still not lighting up. Its being powered by 12v as its a aca pedal. I've replaced these before and never had this issue.

Can anything else be causing this? Perhaps another part that may be damaged?  Its working well and sounding great..just no light

[iainpunk]

have you double checked the polarity of the LED?
might be wise to ask a moderator to move this thread to 'building your own stompbox' board, it has way more traffic.

cheers

[soma89]

have you double checked the polarity of the LED?
might be wise to ask a moderator to move this thread to 'building your own stompbox' board, it has way more traffic.

cheers

Yup double, triple checked polarity

[ElectricDruid]

Does it switch between effect/no effect correctly?

The LED is powered by the flip-flip, so if the flip-flop isn't working, nothing will happen with the LED. But that would make it impossible to switch on/off too, so it'd be pretty obvious.

[soma89]

Does it switch between effect/no effect correctly?

The LED is powered by the flip-flip, so if the flip-flop isn't working, nothing will happen with the LED. But that would make it impossible to switch on/off too, so it'd be pretty obvious.

Yes works fine

[imJonWain]

Is there voltage across the LED/a voltage drop?  Is zener D3 failed?

If the flip flop is working there aren't too many options.  Do some voltage probing around the LED and flip flop.

[ElectricDruid]

JonWain is right. There aren't many options.

If the flip flop is working, the zener D3 or the 3K9 R40 resistor are about the only candidates. Bad joint on one of those, or a cracked trace on the PCB, maybe? Dead zener? Could even be a cracked resistor. Voltage checks from the top (+V) down should help you find where the problem is.