[sdiy] Roland CMU-800R transformer query

[Todd Sines]

I have two CMU-800R’s, one 120v, the other 220v. The 220v model is rock solid, whereas the 120v model is somehow DOA but in mint cosmetic condition. 220v has a 245-231D (21114A) transformer and 117v has a 245-231C (30414A) transformer. I can swap the 291-451 power supply boards to either unit and get the main PCBs to function correctly; but I cannot get the 117v transformer to function at all. There’s not much happening on that 052H348B sub board; a thermal fuse, a glass fuse, AC in, power switch, and DC output (white, brown, red)

When I measure the PSU board from the 220v I get l 20v, GND, 45v, GND, and 15v off CN1 pins 1-5. When measuring the 117v transformer, I get nothing on all pins. 

Where might you investigate— or find a compatible replacement 117v transformer, which I suspect to be the culprit?


Todd

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20230226/d1f0bfb9/attachment.htm>