Fresh Yamaha psr ew400 keyboard power issue

Jun 5, 2018
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I just bought a yahama psr ew400 serieskeyboard yesterday. The seller delivered it to me himself but because it was late in the night, we couldn't test it before he left. I brought it home and that same night connected the adapter and turned it on. It only lasts for barely 5 seconds then it goes off again. Have turned the 'auto power off command' too off yet it keeps going off after I have turned it on. Please help me out. I'm stuck. Is it adapter problem, keyboard problem or what else may the problem be? Fresh Yamaha psr ew400 keyboard series. Please help me out. Thank you.


I meant to play that note!
Jun 6, 2014
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Is it the correct adapter? What's the label on it say?

I suppose you could see if buying a new adapter for it resolves the issue, and I generally like to think the best of other people unless they give me a reason to think otherwise-- but I can't help wondering if the person who sold it to you was aware of the problem and hoped to leave with your money before you noticed the issue and refused to buy the keyboard?

If it's a problem with the keyboard itself rather than simply a bad adapter, then it's possible that it might be a simple and fairly inexpensive fix for someone who has the correct replacement part(s) and the know-how to perform the maintenance. But I don't know anything about repairing keyboards or other electrical/electronic equipment, so if it were me then I would either return it to the seller for a full refund if that's possible, or take it to a certified repair person (if the keyboard is still under warranty), or buy the Service Manual and see if I could find someone with the knowledge and tools to diagnose the issue and repair or replace any faulty parts.
Jul 2, 2017
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Hi there, audio tech here. Could well be just a dry solder joint on the power input socket, or if is not the original power supply adapter, it could be that the current is not enough, even though the voltage could be marked as correct. It may be enough to just start the processor and light up the display, then not enough to operate the sound amplifier if you play the keys etc. Just try to gently put sideways pressure on the power jack to see if the power will stay on, that could confirm a bad solder connection on the socket. I have had my 400 opened recently and other than an umpteen hundred screws, it is an easy operation for even a basic tech to do. The power socket is easy to get at the solder points to rework them. But, first, check the power supply for the current supplied, mine is 16 volts DC output @2.4 amps current. If it is not the original Yamaha power supply, even the plug could be the wrong size center hole, making it too loose to make a good connection. You can use after market supplies, but they need to be a proper fitting plug, at the correct polarity, and the same voltage, or very close, and at least 2.4 amps current. If I can be of any further help, please ask. Cheers Geoff

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