Poly-61 MIDIfied!

Finally, after two years, I installed the CHD Elektroservis Poly-61 MIDI retrofit kit!
So why did it take so long? First and foremost, I'm lazy, OK? Takes me forever to get my thumbs out and actually do something that I really want to do.
Second, and this is a practical reason, I didn't have any good way of making a 16mm diameter hole for the MIDI connector, and I sure wasn't going to have a dangling MIDI-connector next to the synth.
Most people don't have drilling machines that can handle drills with 16mm diameter.

One way could be using a conical drill, preferably stepped. That seemed like a good way to screw everything up since I don't have anything to keep everything in place with. No vise, no pillar drill...
So, after winning a 5/8 inch (15.875mm) hole punch on an online auction, I got to work the same day it arrived in my mailbox. If you don't know what a hole punch is or how it works, look it up.
It's really great!

Conductive discs for Poly-61 keyboard

Tried a new keyboard repair

I had ordered a keyboard repair set for keyboards using the "rubber membrane with carbon peg against PCB traces"-style contacts.
These are used on many keyboards such as the Juno-2, JX-8P, Polysix and of course Poly-61.
Cleaning the PCB and the carbon only seems to remove the very worst of the grease and dust but I didn't get a feeling that the keyboard was really "like new" in terms of triggering afterwards.

So, I decided to try these things...

You can see how thin they are. They come pre-punched with an adhesive so you peel them off of the tape, like little stickers.

Some recapping on the Poly-61

Nasty caps
So, while I had my Poly-61 open and I replaced the buttons, I noticed some of the caps didn't look too healthy...

Poly61 key rejuvenation

Replacing the buttons

The two boards with the 17 buttons. Replacements in the bag. Red write button cap already pulled.

Enough idling! I decided it was time to replace the set of buttons on the Poly61.
I had previously ordered a set of switches for the buttons from vintageplanet.nl but never took the time to replace them.

Why does everybody hate the Poly 61? Even my cat..

Well, I'm gonna spare you most of the details. But..

One of my cats just puked on the keyboard of my Poly 61.
Come on! No synthesizer deserves that kind of disrespect!
Luckily it was easy to clean off.

Any negative comments about cats will be removed.
I love my cats.

Replace Poly-61 battery with Lithium battery

Just a quick update. I made a small board out of strip board and placed a holder for the coin type Lithium batteries that are so common (CR2032). I put a schottky diode in series with it to prevent the reverse charge current.

I'll just put a photo here and then if you're interested you can read the rest of the boring details :)

Poly 61 is "almost" working now

Dead keys
Normally you'd expect an old synthesizer to have problems, for example scratchy pots, dead voices, leaking batteries and dead keys.
Well, the Poly 61 was completely silent when I got it. It lit up and I could edit the presets and store them and everything, but there was just no sound anywhere. Also, I saw the leaking battery.
I was expecting a lot of hopeless searching for errors but I was pleasantly surprised...

Korg Poly-61

One of three synthesizers I bought at the same time.
It is also one of two (the other one is the Matrix-6) that does not work.