This Roland CR-78 CompuRhythm Vintage Drum Machine came in with just one pattern playing and some strange behavior when pushing fill in etc. Belive it or not but someone (previous tech?) did not carefully solder it`s repair or modifiction and left over some tin which then fell in between two legs of an IC which created a short between two legs and a resistor. Well, taake a closer look yourself…
After removing this tiny bit of tin the Roland CR-78 came back to life and all presets could be selected. But I noticed, that not all instruments were playing (correct). This was a mixture of bad components (trimmer) and bad solder joints.
So I corrected that. What I then found were all electrolytic capacitors were leaky (here’s one example)
and were replaced with new, good, quality brand of capacitors.
Finally I cleaned all potentiometers, switches and jacks
to make good solid connection. Just to clarify, I did NOT do this mains modification
Leads me to this…
There are lethal voltage exposed in electronic devices. Unless you know what you are doing, don’t try this. If you following along, you doing so at your own risk.
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!