This AMS DMX 15-80S Vintage Stereo Digital Delay was sent to me for repair in a non working condition. The first problem I encountered was a malfunctioning fuse. If I measured the fuse it measured continuity. But the AMS still didn’t work. But every attempt pointed me to the fuse. So finally I broke the fuse to have a look inside. I my mind there was a lot of corrosion going on which passed the test of a meter but not the 4+amp of the 5V rail.
Main reason for the non working condition and blown fuse seemed to be an exploded tantal capacitor. Now looks a bit like a black muffin.
Next I encountered some heavy leaking electrolytic capacitors. Customer wanted me to re-cap the whole AMS and replace some edge connectors.
The MOSFET of the 5V rail got quite hot. After replacing the MOSFET, Re-Cap the whole AMS, I also renewed all heatsink compount and the mica. I also cleaned the potentiometer.
I’m documenting repairs for my reference and yours.
I do synth restorations and repair with a specialty in vintage synthesizers, drum machines and other vintage gear, based in Düsseldorf, GER.
Get in touch about your synth situation!