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MMD > Archives > June 1999 > 1999.06.24 > 08Prev  Next


Kimball Model F Problems Resolved
By John A. Tuttle

Hi All,  As I said I would, here's what I found out about the Kimball
Model F problems I encountered.

In both instruments, the problems were in the relays which are attached
to the power supply circuit board.  In one unit, the problem turned out
to be a spider's web which was built around the moving leaves, prevent-
ing them from closing correctly.  It's discovery also answered why the
problem was intermittent.  As Bob Baker will verify, spiders and elec-
tronic player pianos do not get along at all! Bob has told me on a few
separate occasions that spider webs were responsible for burned out
note drivers in the Pianocorder system.

In the second unit, the problem was corrosion.  Two of the relays were
so corroded that the relays were frozen.  So, the unit would rewind but
would not roll forward.

Repairing the first unit was a breeze once the culprit was identified.
And I advised the customer to be a tad more vigilant about house
spiders <grin>.   (Like anyone can stop them!)

Repairing the second unit was a mega challenge.  After exhausting
all the player industry parts suppliers, and those having any
connection to Kimball, I contacted the company that made the relay.
They had stopped making it years ago.  So, off to Radio Shack.
Surprise, surprise, they sold a small 12-volt DPDT relay, but the
pin layout was totally different.

After playing with a few ideas, I decided to make a short extension
cord of sorts using single strands of copper telephone wire.  After
soldering the strands to the circuit board and wiring up the relays,
I used clear silicone basin, tub and tile sealant to secure the relay
socket to the board, in exactly the same location as the original
parts.  Since the relays are about 1/2" taller than the originals and
the socket another 7/16" tall, I had to make standoffs so the power
supply could be put back in the piano in the same location without
damaging the new relays.

Once the piano was playing again, the owner told me the whole story
about the unit.  (Why people don't tell the truth from the get-go is
always a mystery to me.... maybe they think someone will try to get
over on them or something).  Anyhow, he told me that the piano had been
in a minor flood.  After it dried out, two other player technicians
were called in separately to fix the unit.  Both swore it was a waste
of time and that it couldn't be fixed since Kimball was out of
business.

Ultimately, the unit was given to the current owner.  He repairs
antique cars, and like me, has a "Never say die" attitude.  After
ballparking an estimate of $400 to fix the unit, I started working.
The rest is history.  The final cost of the repair to the relays was
$280.00 including parts, evaluation and installation.  And now he's
going to start buying rolls ... yeah !

As a final remark, I'd like to say a big thank you to Bing Gibbs in
California, who sent me a copy of the Kimball Model F Service Manual.
Thank you again Bing!

Musically,

John A. Tuttle

By the way, the info from the Smithsonian concerning hide glue is
on it's way.  Same for the info from Bjorn Industries.  More on that
topic later.


(Message sent Thu 24 Jun 1999, 19:41:33 GMT, from time zone GMT-0400.)

Key Words in Subject:  F, Kimball, Model, Problems, Resolved

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