Detailed Boss OD-3 schematic?

[jayn]

I'm looking at a friend's OD-3 where a modder, pre-sale and with some poor workmanship, made some mods that I'm not sure are useful or correct, but the schematics I've found on-line does not cover all the components.  Does anyone know of a schematic that is more complete?

The key thing I'm trying to figure out is why R16 was removed and what the original value was.  I'm guessing it's to increase the brightness of the LED (which was replaced), but I'm not sure.

Also, D12 was removed.  I'm wondering if this is a good idea and/or whether it should have been jumpered.

Thanks to anyone who can help.

[theehman]

R16 was 1.2k.  If it was removed the LED wouldn't work.
D12 is one of the clipping diodes.

[Dragonfly]

The best mod, IMO, for a OD-3 ...

clip and remove D6 and D7... VERY slightly less gain, but a much less compressed tone.

[jayn]

R16 was 1.2k.  If it was removed the LED wouldn't work.
D12 is one of the clipping diodes.

Super, thanks.

That explains why the little LED PCB thingee was removed.  The LED is a super bright white one and it now floats and appears to be directly connected to the wires connected to the 3 and 4 position on the main board (appears because it's all wrapped in electrical tape and I haven't bothered to take it off since it works).  So, that resistor now appears to be doing nothing which, i guess, is why it was removed and jumpered.

Would anything happen, or stop happening, if I jumpered D12?  I will probably try some new diodes in there for kicks while I'm taking some of the tone section mods back to stock values and cleaning up some of the solder joints.

[jayn]

The best mod, IMO, for a OD-3 ...

clip and remove D6 and D7... VERY slightly less gain, but a much less compressed tone.

Thanks...I'll try that, also for kicks 

[theehman]

Would anything happen, or stop happening, if I jumpered D12?  I will probably try some new diodes in there for kicks while I'm taking some of the tone section mods back to stock values and cleaning up some of the solder joints.

If you jump it, there's a 1uf cap between the signal and ground.  Try it and see.

[stephanovitch]

is it this schematic that you have found?
http://www.axiomdrift.com/schematics/BossOD-3.gif

[jayn]

is it this schematic that you have found?
http://www.axiomdrift.com/schematics/BossOD-3.gif

Yes.  It is posted on a number of sites.

[jayn]

OK...here is my report back for anyone that is interested.

R16 - I tried a few values up to 1K8 and it didn't seem to decrease the blinding brightness of the white LED. Changing the resistors didn't seem to have any other effects.

D12 - tried jumpering it.  The pedal turned into a very dark clean boost without much boost (had to turn up all the knobs to get anything useable, but it sounded fine then).  I socketed this one and tried NOS Germ (from Small Bear), 4148, and LED.  Germ was a bit raspy and thin.  The other two sounded quite good.  I left the LED in as it had a bit more note "ping" to it and a bit less cliche hard rock tone (mild differences though).

I changed most of the modded values back to stock (or close...didn't have all parts on hand).  Cleaned up the soldering in places.

It now sounds quite good.  I like that pedal a lot stock, so I'm not surprised that it would sound better to me now.  The only issue that I'd like to fix is the audible pop when the switch is turned on or off.  It seems like it's related to the bright LED.  But, I might be wrong.

I wish I could describe all this in more technical terms, but I'm a noob and just learning.