Alesis Wedge No Power Repair

A Alesis Wedge reverb machine came in, stating it does not power on, no sign of life.

Diagnosis

First check the power. The power brick marked as 9V AC so it’s a bit unusual for modern DC usage. Upon testing, the brick is dead, no voltage output whatsoever. The brick is an unregulated transformer only converting from 240VAC to 9VAC.

The repair

The repair is obvious, we need a new power brick. However the connector is a rare DIN-4 connector, with two pins on one polarity and the other two on the other polarity. Since it’s alternating current, we first try a direct current to power the device: the LED turns on, backlight turns on, but no display.

Rechecked the diagram found the negative voltage is indeed needed.

The client asked for a permanent solution rather than spending money for just a special connector. I made this adaptor, so that the client can feed a 9VAC from an ordinary barrel connector.

The device is alive again.