Help needed - restoring a Schulte Compact Phasing "A"?

Well … I found one of these in my basement. I remember using it back in the days and it was working fine. I just dug it out and it seems to be not working as it should.


The LFO seems to be running very fast at almost every setting of the “OSC.-Period”-knob, the red light bulb on the front panel is almost constantly lit. The light bulbs on the inside (under the black tape) seem to get just a very, very low voltage. They light up, but hardly to be seen. If I turn the “Modulation”-knob, the sound fades away on the left channel of the stereo-return. I already tried to start/control the LFO by the wiring that was printed on the back panel. No success yet. And it was working fine without anything connected to that DIN-port back in the days. Something bad is going on there.

I’m sure that some of you know the Schulte-Phaser. The schematics can also be found online. But I just can’t read them good enough. :(( What is wrong with this one? How can I fix it? Any idea of where to start? I’ll have to say that I’m a little bit scared of this one because it runs on mains-voltage (230V) …

There shouldn’t be mains voltage anywhere other than in the metal cube, so keep your hands out of there :wink:

(Be careful anyhow)

Have you inspected all the caps? They are usually the component with the shortest lifespan… :slight_smile:

No, I didn’t, although my first guess was a “dry” capacitor, too. Well, they all look good, but what the … :wink:

I guess I’ll have to buy a better multimeter to check them. Do I have to desolder them or can they be checked inside the circuit? Maybe not. Sorry if this is a dumb question. I don’t know anything about electronics as you can see …

Well, just watch a few tutorials on it. :slight_smile: It’s best to know your tools. You shouldn’t have to desolder them just to check the values. Make sure to use as little amps and volts as possible. And make sure to let it rest for a while after unplugging it.