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Repair and disassembly guides for electronic keyboards.

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Digital Piano - Power Unstable (Repeating On and Off)

After turning on, my digital piano (Yamaha Clainova CVP 83s) works for some time and then dies with power light off. After a while, the light goes back and works again but then dies. This repeats forever.

I have checked the power supply and changed the power plug of the piano. It does not work. What can I do?

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Thanks for your quick response. When I said “I have checked the power supply” I just meant I have tried the home power sockets on the wall just to make sure that it is not something wrong with my home supply.

Actually I’m not familiar with electronics. Can I ask -

a. How can I check whether “all these voltages are still available when the power “dies”?”

b. How can I check “that the Power switch is OK and that the contacts or the connections aren’t being “intermittent” ”? When the power light goes off, I switch the power switch button off and on again but the light does not go on and the piano does not sound.

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I turn on my keyboard and it stays on for 6-7 seconds and then turns off. I keep trying to turn it on and i checj the plug and everything seems to be fine. Please note that my keyboard is about 3-4 years old so it might just be that it's old.

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My piano turns on the light comes on but it goes of again

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Hi @fhcemothers ,

When you say that “I have checked the power supply…..”, what have you checked?

Looking at the service manual on p.6 indicates that the Power supply provides +5VDC, +8VDC, +15VDC and -15VDC to the piano circuits (see image below)

Have you checked that all these voltages are still available when the power “dies”?

Also have you checked that the Power switch is OK and that the contacts or the connections aren’t being “intermittent” (due to vibrations when the piano is being played perhaps).

With the power totally disconnected from the piano, use an Ohmmeter to test for stable continuity through the Power switch.

Just a couple of tests to hopefully try and isolate the problem.

Block Image

(click on image to enlarge for better viewing)

Update (12/23/2018)

Hi @fhcemothers ,

To check if the power for the piano (not only the AC supply power, but also the DC power, derived from the AC supply, for the electronics) is still available when the indications are that it is off, you need to gain access to the power board in the piano and locate the supply rails for the various voltages supplied to the other boards.

Then you need to check if all the supply voltages from the power board are present and of the correct value or not and go from there depending on results.

You need to be safety aware when doing this as you are working in a circuit where lethal voltages are present and also when testing for the DC voltages you can cause more problems if you don't know what you're doing, e.g. accidentally applying a short circuit between components with your test equipment.

You said that turning the Power switch off then on again doesn't turn the piano back on, how do you get it to turn on again?

Since you say that you are not experienced in electronics, it may be better if you contact a reputable, professional electronics repair service, preferably experienced in digital piano repairs and ask for a quote to repair the piano,

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I'm having the same problem, all my electricity and voltages are OK, could it be something to do with the piano itself and how do I fix that

さんによる

Same problem with my Clavinova CVP-7 .. sometimes the on off switch works and the piano turns on, sometimes it doesn't work and nothing happens/totally dead. Seems to have a mind of its own to when it wants to function. Is there a way to buy a new switch for this vintage 1985 product?

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Hate to discard this vintage piano for the price of a simple switch, but if it doesn't work, it's worthless other than to hold some knick knacks.

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@j_goltz ,

No service manual or part list is available online but access the switch on the piano to see what it looks like and how many connectors etc at then try here and check of you can find a suitable compatible replacement switch

Working out the configuration may be hard but if it only has the two connections most likely they are just a make contact. Don't know whether the switch locks down or not but if not then it will be a "momentary" make switch

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I'm having the same problem. My Kawai ES-8 is turning on and off by itself randomly. If it works for a minute than I can´t switch it off. The push button power switch doesn´t respond. On other occasions the power button works and switches the piano on and off properly. What can I do?

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Fhcem Others さん、ありがとうございました!
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