Repair Fried EHX Nano Small Stone

[jbar93]

Hi guys,

The other day I wasn't paying attention and accidentally plugged my 24V centre positive power plug into my EHX nano small stone which uses a 9V centre negative plug.

Since then the pedal just makes a high pitched whine when engaged, regardless of switch/knob position and no guitar signal sound comes through.

I have been looking for a schematic online to check whether it has reverse polarity protection or not to decide whether it would be worth attempting to repair.

Does anyone have any advice regarding a schematic or where to begin regarding the repair?

Cheers

[bluebunny]

Small Stone schematics are well-known and widely available, but they may not show protection devices (like they may not show jacks).  We would be better off seeing some pictures of the board.  If the magic smoke escaped, it should be easy to spot.

[jbar93]

Attached are the images of the board. The diode does not look visibly damaged. I also tested it with a multimeter and it appears to be functioning normally. Only passed current in one direction and the multimeter displayed 0.666 which I believe is within normal limits.

[duck_arse]

is D2 missing a corner of its epoxy?