Hi. Thanks for all the info here. Will the P250 even complete a factory reset without the ROM boards? Does it need them to complete the reset? I am wondering if this is my problem. This thing sits 45 min. then finally comes on and is screaming. I try to reset it and it never seems to complete.
Well, Iām back at it after a few years. I had to retire to find the time. I have Idād all the capacitors on the MA60 board and will order all parts and rebuild BOTH of the MA60ās I have. The Circuit Board number says Yamaha XQ393 and the part number box says VT144301. The board is an MA60 J-U meaning Japanese and USA model. (FYI, These AND the transformer are available online from All About Music Parts. Yamaha VT144301 VT144300 MA60 P150 Power supply and Amplifier CVP CLP | eBay ) Then I will recap the P250 DM Main Boardā¦(still not available anywhere). .That will be a bit more difficult with the small parts. Stay tuned! 
Well all 30 capacitors I have now been replaced on my āspareā MA60 power supply.
I was able to buy them locally in Burbank at TAW Electronics. That is a single-sided traditional circuit board. NOW looking at the DM Main Board there are 30+ surface-mount capacitorsā¦some close together. I do not have surface mount (SMD) capacitor removal/replacement experience. So I will do my research, get the parts and create my list and try to find a good SMD specialist here in Los Angeles. If you folks know of a better idea please chime in.! 
I done all the SMD caps on a CVP-501 to no avail and also done same on an Electone HC8 with no good result either ā¦ to find out why yours is not working I think itāll be better to chase down exactly what is wrong than just replace caps. If it comes down to a bad ROM chip then there wonāt be a solution anyway and you spent a lot of time, effort and money on ā¦?!
Hi Werner! There is one Rom Chip (WML or WMH) available on Syntaur. But how would I program it?
I do have another P250 here. I can swap parts to identify the bad part. I had done this before and it came down to the DM board. My wife wants me to toss the whole keyboardā¦or part it outā¦and Iām not ready to do that! And most folks know that the shipping these days for a very heavy P250 is not practical. and very expensive.
I just replaced most of the caps on the main board. It didnāt help mine in the least. Instead of replacing them all I used an in circuit cap tester. Some were very bad, some bad, some were good. In any event my issue is with something other than the caps.
Ah
And there are Rom boards.
I will try to swap those also
The recapped MS60 power supply resulted in the proper fast boot process! But the audio is distorted. Next full reset and the saga continues!