Hello Damon. Sorry for the long delay in responding, but I've been busy (sold my house, then moved, then replaced my old PC with a new Mac Mini).

As for the info about those spacers, I replaced them as soon as I bought my MP4 because there were some keys already "flaky" when I got it.

If I remember right, I was looking for plastic (nylon) washers, or spacers that I had lying around in my stuff. I found only about 4 of them, but it was enough to see if they were the right thickness to bring the PCB a little closer to the keys. They were about half the thickness of the originals, and the right diameter. So after a successful experimentation, I when to my local hardware store and bought the 8 more needed to replace all of the originals (12 in all).

The thickness is not too critical, as long as it's not less than half the thickness of the originals (we don't want the keys to push too hard on the rubber contact so as to not damage them). So, just take one out and compare to what you can find. Don't worry about the two little clips of the originals, they're just there to hold them in place. The new ones will be held by the bolts going through them so it doesn't matter, they'll just be a little harder to install.

Like I said before, since doing that mod, never once did any key refuse to play. Only drawback: the keys start playing a little earlier in their travel downward, but I can live with that.

Note: it's very important that the new washers/spacers be of non-conducting material (such as plastic) in order to prevent any shorting out of electrical signals on the PCB.

Alain.

--- In korg_mono-poly@yahoogroups.com , "scituate_mass" <sneakyflute@...> wrote:
>
> Hi Alain,
>
> If you have the info on hand, it would be great if you could supply information about the parts (e.g., what thickness worked, part number or source, etc.) that you used in modding the contacts, as mentioned below:
>
> "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. "
>
> Thanks!
>
> Damon
>
>
>
>
> --- In korg_mono-poly@yahoogroups.com , "Alain" <hubertalain@> wrote:
> >
> >
> >
> > 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.
> >
>