An (almost) new keyboard for my Prophet

gstopp at fibermux.com gstopp at fibermux.com
Tue Apr 2 17:54:54 CEST 1996


     Hey Juergen,
     
     Are you thinking of putting a Pratt/Read keyboard assembly into your 
     OB-8, to replace the Panasonic keyboard? If you are please let me know 
     because I have a spare Prophet 5 keyboard and I've been thinking about 
     doing the same thing. The OB keyboard tends to get dirty if not used, 
     and whenever I'd take it out to play somewhere I'd have to disassemble 
     the keyboard for cleaning before hand.
     
     I know that the OB uses a diode-isolated octal group select, and that 
     the P-5 uses the same thing, but wouldn't it be great if the 
     connectors were the same?
     
     Physically I think there's room - I seem to remember a couple of spare 
     inches between the back of the keyboard and the circuit boards (the 
     P-5 keyboard is deeper than the OB's).
     
     The OB's circuitry does not seem to detect the rubber contacts well 
     unless they have been recently cleaned (like a few hours). I have used 
     the same rubber contact keyboard assmebly in my own digital designs, 
     and they NEVER have a problem, so I wonder if the OB circuitry will do 
     better with J-wires.
     
     Another rainy-day project, I guess....
     
     - Gene
     gstopp at fibermux.com


______________________________ Reply Separator _________________________________
Subject: An (almost) new keyboard for my Prophet
Author:  Haible_Juergen#Tel2743 <HJ2743 at denbgm3xm.scnn1.msmgate.m30x.nbg.scn.de>
at ccrelayout
Date:    4/2/96 11:05 AM


Hi!
     
This weekend my Prophet 5 was kind of "born again".
It is astonishing what a few tiny pieces of rubber can accomplish - 
but let me tell you one by one.
     
I always thought the keyboard action of my Prophet 5 was rather good;
at least in comparison to many other synths I have played. But when Rich 
Marshall came to visit me last year, he said it could still be improoved 
by replacing the bushings. Now he has sent me a set of these rubber 
pieces, and last Saturday I disassembled the Prophet and replaced them.
     
It was a lot of work, mainly to remove the keyoard from the Prophet 
(I wished they were built like Oberheims- sigh!). Then I removed the 
black and white key caps (and also cleaned them by this occasion). 
Now there was a decision to make: should I disassemble the keyboard 
completely, or use a dentist tool to get hold of the old bushings.
The manual as well as Rich seemed to highly prefer the dentists tool method, 
but I wasn't so sure. I decided to remove one key at least to see what I was 
going to do, and things became much clearer then. Removing and replacing
the keys isn't that difficult at all, IMO. So I removed another four keys 
and
practiced removing the bushings on these keys. I found that with a thin 
screwdriver it worked very well: pull the screwdriver between the metal and 
the rubber, then cock the crecdriver a little to get susufficient friction 
between
srewdriver and rubber, and then carefully draw back the screwdriver and the 
rubber with it.
As I found that the method worked, I removed the other bushings without 
disassembling the keys. It worked fine on most of them. Two or three were
a little reluctant, but instead of cutting them to pieces and then removing 
the
parts (as suggested in the manual), I simply removed these few keys 
like with the first ones. Easy.
I highly recommend this method, which is a mix of the manual's method 1 and 
2.
If you haven't worked on a keyboard action before, replace a few keys
to learn what you are doing and to practice, and then you can do it blindly 
(i.e. with keys in place) on most of the other ones.
     
The results - absolutely great!
A smooth and precise action. No more sound of metal striking hard on metal, 
but all nicely softened by the rubber pieces as it obvoisly was intended
by the designers.
Rich, you have not promised too much - it is wonderful!
I think that many people simply don't know (I didn't either), how their 
synthesizer's
keyboard action was when the instrument was new. You only get the impression 
when you see the difference.
     
Is it worth the money? If you really *play* your synth with your hands (and 
not
only by Midi) it is worth it all for sure. "It all" means the money and the 
time for
work. As often, the work is by far the larger amount than the cash.
This set of bushings was a gift from Rich, so I didn't take much risk. But 
I won't hesitate to buy another set - and I surely *will* as soon as I can 
get
a new keyboard for my OB-8. It's high time to replace the Obie's ugly 
rubber contact keyboard ...
     
JH.
     




More information about the Synth-diy mailing list