Super Overdrive Circuit Diagram & help needed!

[mcclano]

PLease can any one give me a Boss SD-1 Super Overdrive circuit diagram?!?!
It broke and I need one to try and fix it!
any help on where to get one would be really helpfull!!!!

you don't realise how good a pedal is till it breaks!

[mcclano]

Re: Super Overdrive Circuit Diagram needed!

Dude you rule!!!! I didn't think any1 would give me one!
Hopefully my dad can use that to fix it!
anymore would be great from any1 else.

[Kent S.]

Re: Super Overdrive Circuit Diagram needed!

Dude you rule!!!! I didn't think any1 would give me one!
Hopefully my dad can use that to fix it!
anymore would be great from any1 else.

Ah, dude, it's not like multiple schematics are going to change or anything ..lol
That actually came out clear, download it, save it as a bitmap, and then you can resize it in photoshop. The SD-1 is pretty simple.

[mcclano]

Re: Super Overdrive Circuit Diagram needed!

You might have an idea why it aint working.
1st off, there is no sound at all with or without the switch on.
2nd is, there is no sound when Im puting the lead into the input meaning that no signal is getting from the imput to the output.
The check light is lighting up so power is at least getting to the light. Maybe something is stoping the power getting thru the whole pedal?
3rd it feels like when I put the lead into the output that it doesnt fully click in properly (sort of like it clicks then slides the rest of the way) hehe.
Anyway My dads an electrical engineer and he looked at it for an hour and could figure it out he said he need a diagram.

[mcclano]

Re: Super Overdrive Circuit Diagram & help needed!

Great! Thanks for your help!

[Kent S.]

Re: Super Overdrive Circuit Diagram needed!

You might have an idea why it aint working.
1st off, there is no sound at all with or without the switch on.
2nd is, there is no sound when Im puting the lead into the input meaning that no signal is getting from the imput to the output.
The check light is lighting up so power is at least getting to the light. Maybe something is stoping the power getting thru the whole pedal?
3rd it feels like when I put the lead into the output that it doesnt fully click in properly (sort of like it clicks then slides the rest of the way) hehe.
Anyway My dads an electrical engineer and he looked at it for an hour and could figure it out he said he need a diagram.

The third one doesn't have much to do with it, unless the connection to the tip is gone, or a wire from the input or output connection has come loose. Then the pedal wouldn't get any input signal, but you should still hear more hiss when the effect is engaged with the controls cranked.
If the output buffer is gone you will get no output (or if the output connection has come loose, if the input is gone, you should still get some output hiss (if the output is functioning properly), because of the noise of the circuit itself.
The switching fets could be gone, either one or both locked in one state ...as they either let the signal thru, or block it ...they work in pairs to determine if you have effect or direct signal.
Does the led turn on and off when you click the pedal, if no (it stays on) then the flip-flop has a problem, if yes then the switching Fets may have the problem.
I forgot to label which are the inputs buffers and Fet, and which are the output buffer and Fet; but I think it's pretty clear. It's getting power so you know that's not an issue, it could be the bias supply or a filter in it, but I doubt it would offset it enough to mute it. Download both copies and print out this text for your dad.

[Norman_T]

Re: Super Overdrive Circuit Diagram & help needed!

This might also help if you want to mod it as well, might be an idea if your dad is an engineer and can get the parts.

[STRATDELUXER97]

Re: Super Overdrive Circuit Diagram & help needed!

Have your Dad first check the power supply diode up alongside the 9v power supply jack..It's a very common source for no pedal operation on Boss pedals...Next check all wiring connections on the board and all diodes in general....If you have no LED when you step on the pedal and no sound at all,you more than likely have a power supply problem..If you can't fix it,send it to me and I will...I Mod these pedals all day long and I've seen alot of the same problems that the pedals exibit..

John

[mcclano]

Re: Super Overdrive Circuit Diagram & help needed!

Thanx guys!

[mcclano]

Re: Super Overdrive Circuit Diagram & help needed!

Ok we've got sound but there are two problems!
1 is that we've got the wrong transisters so it sounds like a weak fart!
2 there is no difference with the overdrive on or off (maybe due to the transisters?)
Anyway could some1 please tell me the exact specs of the Q5 and Q6 transisters? I'm pretty sure they are both the same.
Thanx!

[Kent S.]

Re: Super Overdrive Circuit Diagram & help needed!

Ok we've got sound but there are two problems!
1 is that we've got the wrong transisters so it sounds like a weak fart!
2 there is no difference with the overdrive on or off (maybe due to the transisters?)
Anyway could some1 please tell me the exact specs of the Q5 and Q6 transisters? I'm pretty sure they are both the same.
Thanx!

Ouch! I've been away for a few days, First off your switching fets aren't switching and /or you filp-flop circuit isn't functioning (that's the TTL logic array that gets the fets to switch ...if the LED goes on and off when you switch the pedal, but it doesn't change the effect on or off, then it's more than likely one or both of the switching fets ... that's that in regard to switching) ...
Q5 & Q6 ... 2SC732
Q3 & Q4 (flip-flop) ...2SC1685
Q1 & Q2 ... 2SK30A ... The source connects to the 22k resistors, the drains are the other connection (effect out, or direct off the first buffer {Q1}), the gate hooks the the collectors of the flip-flop array, Q1 switches the effect side,Q2 switches the direct side, the cathode of the LED hooks into this also (off of Q3's collector).
2SC2458-GR can be subbed for 2SC732; 2SK118 can be subbed for 2SK30A
Also, other possiblities are 2SC2240, 2SC2459-GR for the 2SC732; However they normally run them off of 8V at the collector instead of 9V (bias must change to reflect this, further a 2SK184-GR could be used in the 8V scheme as well ... drain takes place of collector, sourse takes plae of emitter.
I would go that route though, you should be able to find the others, I think even Radio Shack can order them, they just list them as Japanese transitors, but any electronics supplier will have them. Or look up a sub for them on the web from one of the manufacturers.

[mcclano]

Re: Super Overdrive Circuit Diagram & help needed!

Woah thanks alot for all you help! Why would all these things just go at once?

[Kent S.]

Re: Super Overdrive Circuit Diagram & help needed!

Woah thanks alot for all you help! Why would all these things just go at once?

They don't! That's generally speaking of course, unless someone does something to really (forgive the analogy) screw the pooch. You don't know that all of these things have happened yet, your dad is an EE, so he'll be able to figure out what's what. End of story.