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Grand Piano synth project

This post is a work in progress

I saw this piano key bed on eBay for .99p no bids and no reserve and instantly thought, Why not turn this into a usable piano synth?

I picked them up from a lovely family near Dorking in a pretty little village called Shere. They were going to either throw it away burn it or turn it into a table, But decided instead to put it on eBay just incase some nutter like me would put them to some other use!

Planning the Piano Synth build

The inital idea was for this to be a

Inspecting the Technics Keyboard PCB

Technics PCM E33 Keyboard PCB
Technics PCM E33 Keyboard PCB

Looking at the PCB layout it looks like i would need to keep the existing PCB intact for this to work. The microswitch is part of the PCB and i would have to do alot of work to externalise the electronics, For that amount of work it would be easier to turn this into a simple MIDI keyboard. Its not really the end result i want.
I invisiond this to be a standalone, Unique, Custom piece that works on its own, maybe circuit bent or modified in some way to get some experimental sounds out of it.

Technics PCM E33 PKB Keyboard Circuit Diagram
Technics PCM E33 PKB Keyboard Circuit Diagram

I took the Technics keyboard appart and found what i imagined from the diagrams. The switching is done on directly on the PCB via the grey rubber pads which house an internal contact. The original keybed depreses the rubber cup and it makes contact across the two pads on the PCB.

Technics PCM E33 Keyboard PCB
Technics PCM E33 Keyboard PCB

Luckily fate has it that the PCB and Grand Piano keybed align pretty mch perfectly! This will definitely make things easier. Its going to be a case of mounting the PCB on a frame which the hammer action can engage with the rubber cup.

Technics PCM E33 Keyboard PCB
Technics PCM E33 Keyboard PCB

Restoring and repairing the Piano Keybed

The Grand Piano keybed wasnt in the prestinest of conditions. Apprently it couldnt be tuned hence why they had pulled the bed out of the piano frame. I tested each key and found the hammers where mostly catching on eachther, some of the Keys did not return from bent backchecks.

I repaired and restored all the actions on the levers ready for figuring out some kind of frame for the PCB to mount on. Some of the hammers i had to reglue being loose and some just needed a little adjustment.

As you can see none of the Backchecks or repetition levers lign up so some more servicing and repair might be needed to get these working 100% again.

Grand Piano Keybed Key Action
Grand Piano Keybed Key Action
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