Broken Boss Sd-1

[slmkn]

Recently I bought a Boss Sd-1 and tried to test it with a Zoom G3 multieffects powersupply ( AC 9V 500mA). Guess that wasnt a truly clever achievement from me... What did I sent to afterlife? Any help appriciated, thx!

[jdub]

It's a DC-powered device.  If you used an AC supply, the damage could be extensive.

[GGBB]

What I would do is open it up and look for burnt components. I'd replace anything obvious and see if it works. Beyond that it gets more complicated but blind replacement is always an option (ICs etc.).

[slmkn]

Yeah I opened it, couldnt see anything but maybe I busted the ic/transistors. Thought it was a common problem that someone connected wrong supply, though couldnt find anything about it. Thanks for the replies, guess I'll swap the ic first

[GGBB]

Check for continuity across diodes and resistors in the power section. It is fairly common, and usually a resistor or diode in the power section dies. A schematic will probably help narrow your focus. I don't think there's much in that circuit that could get fried by 9V AC except diodes, power supply resistors, the IC and polarized caps. Any tantalums in there? They'd almost surely go.

[jdub]

From R.G:

The worst thing you can do to a pedal short of melting it down in a pot of liquid iron or pounding it to bits with a sledge hammer is to connect up a power adapter that provides AC instead of DC. There are several commercial pedals which come with their own adapters that supply 9VAC, not DC. The adapters have the same power adapter plug as other DC pedals, so it's easy to plug them into a DC-only pedal. What this does is to first destroy any reverse-diode protection circuits. Then it kills the ICs, then the electro caps. After that, it may kill transistors and other parts.

If you don't know what killed the pedal, then first replace any obviously fried parts. Replace the reverse-protection diode, and any electrolytics with bulges or leaks. Power it up on a battery and read the DC voltages on the ICs. If the voltages are not within expected tolerances, especially if they are all almost 0, start replacing all the electro caps. Still not working? Start replacing ICs. Still not working? Start replacing transistors and diodes.

Link to the whole thread:

http://www.diystompboxes.com/smfforum/index.php?topic=55003.0;wap2

Good advice here.

From my own experience, how long it was connected is a factor.  In my case (I forget what effect it was) I luckily only had the AC connected for a second or two; it fried the protection diode across the power supply as well as the IC, but the polarized capacitors and transistors made it through OK.  Hopefully you'll get lucky!