ME-25 - Beware the reverse polarity PSU hazard...

Started by elmo7sharp9, May 09, 2017, 05:52:51 AM

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My ME-25 now operates only on battery power, following the accidental connection of a Yamaha PSU.
That fact that it's still working at all is a bonus...

Suspecting a blown protection diode, I tried bridging each diode near the power socket with a known-good diode. No luck... I've no idea what's wrong and I reserve SMD surgery for when I am certain of what I'm doing. If it ain't TOTALLY broke, don't attempt to fix it  ;) 

I will now bodge a second 2.1mm power socket in between the battery pack and the PCB. Crude, yes -  but I can't continue on batteries.


I've just blown another one of these.  ::)
Same symptom, different cause...

This time, I used an old Roland supply for a keyboard.
It's unregulated and measures 14 volts off-load.
All other devices (Including the ultra-choosy TC Electronic Ditto) work well with it.

Down to batteries-only operation, again.

At least I know what to do to fix it...