A pricey used pedal arrived non-functioning - is it a simple fix or a return?

[GibsonGM]

Just that with the person re-selling in between the manufacturer, it's neither the reseller nor the manufacturer's issue any longer.  I agree whole heartedly with the complaints - guys, a protection diode was too much to include??  That is a chump oversight, hell I put them on a 1 transistor buffer.   And a small "Warning: this pedal uses positive ground power supplies ONLY" isn't much to ask for.  But if you break it, you buy it.

[amptramp]

How much damage would there be here?

You have two electrolytics that would have been reverse biased but that isn't too much of an expense to replace.

You have three transistors but they are germanium - they don't suffer the same damage as silicon when they are reverse biased, so they may be OK.  In fact, the first two could be replaced with silicon with no changes to the circuitry.

The last stage uses leakage current bias with a germanium bleeder diode from base to ground.  The idea here is as the temperature increases, the leakage current from collector to base increases but the germanium diode leakage also increases, so you get some cancellation of bias changes.  You would have to change the design to add biasing resistors if you wanted to change to silicon.  That always seemed like a dubious way to bias things when leakage current bias first showed up in transistor radios and it isn't any better here.  The sound will definitely change with temperature.  It might be cheaper to rebuild than to go through the hassle of returning it then fighting about who is responsible for the damage.

Of course, if you rebuild it, add a series protection diode and resistor just to make sure this doesn't happen again.

[Ben N]

I feel for you. The idiot that designed that pedal to use the exact same plug/socket as the near-universal boss power supply, except with the polarity reversed needs taking outside and throwing into a lake! If they think that one badly-phrased message is clear enough, they're a fool. And they didn't even think to add any reverse polarity protection to the circuit, despite having made virtually certain that this pedal would be subjected to reverse voltage. It's so, so stupid. Gagh!

Gee, I wonder who that idiot might be? 🤔

Sorry, do we know?

Fuller puts his name on it, so...

[Delicieuxz]

I have a positive update on this. While the pedal is still not working, Reverb, where I bought it from, with their shipping coverage, has offered to cover the cost of taking it to a tech to be repaired. They were informed that I had used a centre-negative adapter initially.

How much damage would there be here?

You have two electrolytics that would have been reverse biased but that isn't too much of an expense to replace.

You have three transistors but they are germanium - they don't suffer the same damage as silicon when they are reverse biased, so they may be OK.  In fact, the first two could be replaced with silicon with no changes to the circuitry.

This is really interesting. And I hope the transistors are OK, because I trust the original matching and leakage to be good and I liked that this Soul Bender had higher HFE values compared to a lot of others, and also so Reverb won't have a higher bill to cover in the end.

[Delicieuxz]

I've had a tech look at the pedal, and they said the pedal works fine when they tried it with an AC adapter of the correct polarity. They said it didn't work when I tried it with battery power because the 9v power jack is faulty and only works with an AC adapter. Replacing the power jack should fix it.

That's some really good news. The tech thought all the components on the board are still good after being hit with the wrong polarity. I hope it won't have worn the transistors and that the pedal won't produce more noise or anything. I read a post somewhere that said they can become noisier as a result. But then, I've also been told that it shouldn't affect them at all.

The tech will swap the power-jack wiring to centre-neg, and add a polarity-protection diode while they're at it.

[Ben N]

Best possible outcome! Your pedal is probably better than new, but even if not, you know what issues you may have and how to deal with them. Enjoy.

[VSmolsky]

I've had a tech look at the pedal, and they said the pedal works fine when they tried it with an AC adapter of the correct polarity. They said it didn't work when I tried it with battery power because the 9v power jack is faulty and only works with an AC adapter. Replacing the power jack should fix it.

If it's true what your tech says, then the transistors didn't fail even though current was flowing to them with the wrong polarity. The pedal was fine, and the only issue it had was the battery power.

[johngreene]

I've had a tech look at the pedal, and they said the pedal works fine when they tried it with an AC adapter of the correct polarity. They said it didn't work when I tried it with battery power because the 9v power jack is faulty and only works with an AC adapter. Replacing the power jack should fix it.

That's some really good news. The tech thought all the components on the board are still good after being hit with the wrong polarity. I hope it won't have worn the transistors and that the pedal won't produce more noise or anything. I read a post somewhere that said they can become noisier as a result. But then, I've also been told that it shouldn't affect them at all.

The tech will swap the power-jack wiring to centre-neg, and add a polarity-protection diode while they're at it.

If you wire it with a center negative power jack then you must remember that the chassis will be connected to +9V with respect to the outside world. So you still have to use a separate, isolated power supply. You cannot split a power supply between this pedal and another 'boss-type' pedal as it will short the power supply.

[Chillums]

I've had a tech look at the pedal, and they said the pedal works fine when they tried it with an AC adapter of the correct polarity. They said it didn't work when I tried it with battery power because the 9v power jack is faulty and only works with an AC adapter. Replacing the power jack should fix it.

That's some really good news. The tech thought all the components on the board are still good after being hit with the wrong polarity. I hope it won't have worn the transistors and that the pedal won't produce more noise or anything. I read a post somewhere that said they can become noisier as a result. But then, I've also been told that it shouldn't affect them at all.

The tech will swap the power-jack wiring to centre-neg, and add a polarity-protection diode while they're at it.

If you wire it with a center negative power jack then you must remember that the chassis will be connected to +9V with respect to the outside world. So you still have to use a separate, isolated power supply. You cannot split a power supply between this pedal and another 'boss-type' pedal as it will short the power supply.

Yeah if it were me I would just ditch the DC jack and just use a battery

[Processaurus]

What happens when the "fixed" pedal is daisy chained with others? The power supply (like 1 spot) is shorted out.

[merlinb]

"tip" meaning the tip of the pin inside the power socket. Seems pretty clear to me.