Boss OD-1B no sound

SuperHorndog · Post by **SuperHorndog** » 25 Mar 2022, 12:12

I have a Boss OD-1B on the bench. Passes signal in bypass but nothing when circuit is activated. I've traced sound up to pin 5 on the RC3403adb chip but I have no sound on pin 7. Is it safe to assume the chip is bad?

CheapPedalCollector · Post by **CheapPedalCollector** » 25 Mar 2022, 14:10

Yep the chip is bad.

SuperHorndog · Post by **SuperHorndog** » 27 Mar 2022, 01:16

I found one on ebay for around $20. Let's hope it's the real deal!

SuperHorndog · Post by **SuperHorndog** » 02 Apr 2022, 21:55

Got the new chip in and I have the same results. I've checked all resistors and diodes and all are good. Maybe a cap?

mauman · Post by **mauman** » 03 Apr 2022, 00:34

Maybe C7 is shorted? Sounds like something connected to that IC pin 7 pulling it down, maybe the OD pot or the wiring to it. Gotta be close by if you have no sound at all on pin 7. Does turning the OD pot change it? If so, it may be something closer to pin 6, maybe as far away as C5, but if so I think you'd hear at least something on pin 7.

Fender3D · Post by **Fender3D** » 03 Apr 2022, 18:18

what's the voltage at pins 5-6-7?

Manfred · Post by **Manfred** » 03 Apr 2022, 21:30

Unsolder the gain potentiometer and connect pins 2 and 3 of the board.
Then you got minimum gain, and the potentiometer as a source of error excluded.
Actually signal should come out then.
Measure in advance with the ohmmeter pin7 with respect to ground to make sure that there is no short circuit.

SuperHorndog · Post by **SuperHorndog** » 05 Apr 2022, 00:14

Pin 5 - 3.85V
Pin 6 - .076V
Pin 7 - .006V

SuperHorndog · Post by **SuperHorndog** » 05 Apr 2022, 00:30

Bypassed the pot and now I have sound on Pin 7 and the pedal works!

Manfred · Post by **Manfred** » 05 Apr 2022, 11:10

SuperHorndog wrote: ↑05 Apr 2022, 00:30 Bypassed the pot and now I have sound on Pin 7 and the pedal works!

I suppose that there is a faulty connection to the potetiometer.

SuperHorndog · Post by **SuperHorndog** » 05 Apr 2022, 15:13

Redid the wiring to the pot and all is good.

Manfred · Post by **Manfred** » 05 Apr 2022, 21:31

Did you also check the potentiometer function with an ohmmeter?

Fender3D · Post by **Fender3D** » 06 Apr 2022, 11:34

0V on pins 6-7 suggests you have a short between pot's pin(s) and GND (enclosure perhaps?)