Korg Forums

karmaR3 · Joined: 25 Sep 2016 Posts: 2

I've had my Korg R3 for about 8 years and never had any problems with it until now. It will power on and the five backlit screens on the top right of the keyboard will light up, but it does not continue booting up. Confused

Yes, I've tried adjusting the contrast knob, but that is not the issue... and none of the other button lights, etc. turn on and there is no sound.

Is there some key combination that I can hold down while powering on so that it will revert to the factory presets? I couldn't find anything useful in the user manual. Any help would be much appreciated... the keyboard is in great condition externally, but I'd prefer to find a fix before going down the route of opening it up and trying to figure out if a circuit burned out, etc. Thanks! Smile

voip · Platinum Member Joined: 27 Nov 2014 Posts: 3769

Do the backlit screens show anything, such as text, or random pixels?

Failure of the R3 to start up could be down to one of a number of possible causes. Bad power quality e.g. power supply voltage too low or electrically noisy, program corruption in flash ROM, a CPU issue, or SDRAM problems.

It would be easiest to start with the power supply, by measuring the 12V output from the mains power supply with a multimeter, and also trying an alternative, known good, stable 12V supply capable of delivering around 0.5 Amps. The connector on the R3 is centre positive.

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karmaR3 · Joined: 25 Sep 2016 Posts: 2

Thanks, voip. The backlit screens do not show anything, just the usual reddish light but no black pixels.

I did notice recently that the power adapter seemed to be overheating. I checked the voltage, and lo and behold it is at about 2.55V instead of the 12V it should be. Looks like I can pick up a replacement Korg KA310 switching adapter for the R3 at about $35 from online retailers. Do you think buying a new AC adapter will be the right fix? Thanks!

voip · Platinum Member Joined: 27 Nov 2014 Posts: 3769

2.55V is way too low. I would have expected at least 12V without a load. Some of these power supplies can come in at well over 12V off load, though the better ones regulate the output rather better.

Replacing the power supply is almost certainly going to resolve the problem.

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