Circut Guru's!(Boss Content)

SonofaMitch

SonofaMitch

New member
okays, I recently came into posession of an older Japan Boss SD-1(Super Overdrive), now here's my problem.....I get signal when the pedal's turned off...but when I switch it on I get nothing, Nada, Zip..

after Doing a continuity Test I found out that this 1 Fuse?/Diode?, Is giving me nothing while everything else is working fine...do you know where I could get one of these...anyone with an SD-1 got any spares?? I need help plz!!!

P.S. it's the one Circled in red..it says on the PCB; D2(5.1)

~Mitch~
 
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Re: Circut Guru's!(Boss Content)

Mitch:
I'm guessing that it is a diode. We have several electronics stores locally that I go to often. If you can find out exactly what you need I will get a few and mail them to you. Save you some time with catalogs, phoning, etc.

Dave
 
Re: Circut Guru's!(Boss Content)

wow thanks Greco....Unfortunatly the only "electronics" places around my place is "The Source"
.....If I can find what I need that would be Most Appreciated!!

~Mitch~
 
Re: Circut Guru's!(Boss Content)

That's a RD5.1EB-3 diode which is part of the LED limiting circuit. I don't think you should be seeing much voltage there at all because it goes to ground. The problem is somewhere else.
 
Re: Circut Guru's!(Boss Content)

I'd check the voltages around the opamp chip, the JRC4558DD. Make sure there's some juice there. Then I'd run an audio probe through it. You can make one from a diagram at diystompboxes.com or geofex.com. That probe saved my butt hours of troubleshooting many times.

The probe will help you find out where the signal is dying out by feeding it signal. Only catch is, you're providing the signal via that probe so you can touch it to all the spots throughout the signal path until you finally hear something. Once you do, the last part prior is the problem. Or, start at the output and word backwards until the signal dies.

If you're not sure what to do, get it to someone who can help you out. If I were local I'd be more than happy to take a look at it.
 
Re: Circut Guru's!(Boss Content)

ok, well I was probing around theOp amp chip and it's giving me signal...as is everything else...Except that RD5 Diode.....even the other RD5 Diodes give me something....and the LED comes on to signal that the pedals on...just absoutly no sound at all

~Mitch~
 
Re: Circut Guru's!(Boss Content)

ErikH said:
I'd check the voltages around the opamp chip, the JRC4558DD. Make sure there's some juice there. Then I'd run an audio probe through it. You can make one from a diagram at diystompboxes.com or geofex.com. That probe saved my butt hours of troubleshooting many times.

The probe will help you find out where the signal is dying out by feeding it signal. Only catch is, you're providing the signal via that probe so you can touch it to all the spots throughout the signal path until you finally hear something. Once you do, the last part prior is the problem. Or, start at the output and word backwards until the signal dies.

If you're not sure what to do, get it to someone who can help you out. If I were local I'd be more than happy to take a look at it.
Click to expand...

Thanks Erik, I learned a lot from this.

Dave
 
Re: Circut Guru's!(Boss Content)

No problem, Dave. I learned all this stuff from diystompboxes.com and geofex.com. Invaluable information if you're in to this kind of stuff if you ask me.

SpHj, what do you mean by "signal"? Audio signal or voltage? What's the DC voltage readings on the opamp chip with the pedal engaged? The pin order goes (according to the photo orientation above), bottom (1 2 3 4), top (5 6 7 8).
 
Re: Circut Guru's!(Boss Content)

it's giving me voltage:P..sorry gotta clear that up...as for what exactly the chip's giving me...I'll have 2 pull it apart agaun haha

~Mitch~
 
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