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.
(click on image to enlarge for better viewing)
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,