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MicroKorg getting power from batteries, not from DC jack
Posted: Mon Apr 22, 2013 4:21 pm
by nicjimbass
I see this is a common problem here, but it seems my problem is a little unique. Obviously, from the title, I can power my MK with batteries, but ever since I bought it (used) the DC jack hasn't worked. I tracked down a service manual, and, using the schematic, I have been able to successfully trace voltage from the batteries through at least the first 3-4 components with a multimeter. When I do the same for the DC jack, I get no voltage at all. In fact, when I have the actual DC jack unsoldered from the board, I get a perfect signal. As soon as the jack is in the board, whether soldered or not, I get no voltage. As soon as it makes contact with the board the power seems to vanish. I've tried 2 different DC jacks, and they both did the same thing. Obviously, since I am not getting voltage from the jack itself, I get nothing from the next components in line, and thus, the board will not power up. Any suggestions? Thanks!
Re: MicroKorg getting power from batteries, not from DC jack
Posted: Tue May 14, 2013 4:10 pm
by cynkh
It sounds like the line from the power jack input is shorting directly to ground which is why it's disappearing. It's probably a capacitor or voltage regulator immediately following the input jack in the signal. I blew a tiny cap on my Alesis Photon and it behaved exactly the same way: I could power it with batteries but the external power jack wouldn't work. The cap basically behaved as a rudimentary (and tiny) fuse.
Hope this helps. Good luck!
nicjimbass wrote:I see this is a common problem here, but it seems my problem is a little unique. Obviously, from the title, I can power my MK with batteries, but ever since I bought it (used) the DC jack hasn't worked. I tracked down a service manual, and, using the schematic, I have been able to successfully trace voltage from the batteries through at least the first 3-4 components with a multimeter. When I do the same for the DC jack, I get no voltage at all. In fact, when I have the actual DC jack unsoldered from the board, I get a perfect signal. As soon as the jack is in the board, whether soldered or not, I get no voltage. As soon as it makes contact with the board the power seems to vanish. I've tried 2 different DC jacks, and they both did the same thing. Obviously, since I am not getting voltage from the jack itself, I get nothing from the next components in line, and thus, the board will not power up. Any suggestions? Thanks!