Well, Steve, this was a very interesting tale of the resuscitation of your MP4 indeed!

Upon reading this fascinating journey, I remembered having had similar thoughts about the weak design of the power supply, and the less than perfect calibration procedure from the service manual. Also, that darn Panasonic keyboard misfiring came to mind too.

Although I performed some definitive modifications on mine that will ensure proper contact for years to come. I simply replaced all the Nylon spacers with thinner ones to close the gap between the rubber contacts and the gold plated pcb. Since these contacts are very similar to the ones in TV remote controls, and having noticed that when those start to be flaky, they WILL still work when pressed down harder, I figured why not for the keyboard of my beloved MP4 also Since my modification (about six months ago) not a single key has misfired.

The transformer hum I had also noticed before (even on my USA model) so I've done another thing there too. I've added a grounded metal shield over the transformer (with some air holes to prevent the already hot thing to get even hotter), taking great care so it doesn't touch the PCB on top of it when the synth is closed up. It's not pretty, but it's inside and it cuts down the hum to almost inaudible levels now.

Anyway, all this to say that your 4 part story was very well written, absolutely pertinent to this group, and in many ways very helpful. I'm so glad that you could get it back to life so you can enjoy this gem again, and I'll feel a little more confident now that my own four SSM2033s could stand the test of time if yours didn't blow out at twice the power supply input !

Thanks again!

Alain.