I recently bought a used Prophet 600. Several of the keys would "clack" when I
depressed them, which is super annoying. I've re-done the bushings on several
J-wire keybeds, and those bushings are readily available. But I couldn't find
any info on this later membrane-type keybed, or anybody who carries new bushings.

I ended up finding some heat shrink tubing that was the exact right fit for the
bushings, and worked perfectly. Below you'll see the process I used to replace them.

**Note** I understand later Pro-Ones had this same keybed, and I'm sure other synths
do too. Hopefully this will be useful to others than just P-600 owners.

The first step is to take off the wooden end cheeks. 5 Philips screws hold in each side.

Next, I flipped up the hinged top to expose the full keybed.

The keys are held in by spring tension and some plastic tabs in the rear. To remove them,
simply push down gently on the rear of each key and push it towards the front of the synth.

The key will lift away. Be careful to not let the spring go flying.

Remove the spring. I put mine in a bowl so I wouldn't lose any. The springs are the same
for all keys, black and white. There's an "Ebony and Ivory" joke in there somewhere.

You need to remove all the white keys first, as they restrict the movement of the black
keys. Chuck D would have something to say about this. I welcome his input.

Here I've removed all the white keys, now ready to start with the black.

Once all the keys are all removed, you can see my bushings were in sorry condition.
Some were missing entirely.

Here's all my keys and springs in bowls. The keys are marked with the note on the bottom
so it's no big deal if they get all mixed up.

Next I took all those dirty keys to the kitchen sink and gave them a bath in warm soapy water.

All laid out to dry.

While the keys are drying, back to the keybed. I've removed all the old bushings, so the
metal tabs are bare.

Here's the label for the shrink tubing I found works best. I ordered it from McMaster-Carr.
Their part number was 7132K74. Inside diamter before shrinking: .25". After shrinking:
.125". Wall thickness after shrinking: .025" (this is key. No pun intended). PVC material.

I cut pieces of the shrink tubing with scissors to fit the metal tabs. One $2.62 pack
of tubing was enough to do the whole keyboard.

Here you can see the tubing on the tabs before shrinking.

Next I used a heat gun to shrink up the tubing. A hair dryer might work for this job, but
I can't promise. Also one of those blowtorchy-lighters held a ways away would probably work.

After shrinking. They don't have to cover the metal completely, but they should come close.

My keys are dry and it's time to put them back on. Black first. All the black keys are the same.

There are little stamped nubs on the sheet metal keybed. The springs HAVE to go on these.
This is probably the most challenging part of the job, but it's not that hard. The ones
that are farther back are for the black keys, which makes it easy to keep track.

Start by positioning the bottom of the spring over the nub.

Then push the key down into place, sliding backwards right at the end to lock in the tabs.

If the key is in correctly, it will move up and down freely and have good spring. And not clack!

I did all the black keys before I started on the white.

Here's the bottom of a key. This is a B. The only key on the P600 that's different is the
High C all the way to the right, and it's totally obvious.

I lined up all the keys in chromatic order so I wouldn't have to go fishing each time.

The white keys go on the same way as the black, but now there's less room to work. First
get the spring positioned over the nub.

Angle it down as far as it will go without raising the spring.

Push down on the rear of the key and slide the tabs in.

Shazam! Make sure the key moves freely down and springs back.

all the keys are done!

Voila! The control panel can be closed and mad synth shredding can begin. This keybed feels great!