Ron is correct that most idler wheel designs are such that the diameter
of the wheel does not affect the speed at the platter. These wheels are
common and used where the motor drives the outer diameter of the wheel and
that same outer diameter drives the platter. The exception to the idler
affecting the platter speed is when the idler has more than one outer
diameter such as those wheels used the the early RCA 45rpm changers RP-168,
RP-190, and some similar changers. These designs have two tires on them
with different outer diameters. The motor drives one diameter while the
other diameter drives the platter. On these type idlers it is critical to
maintain the RATIO of the two diameters when resurfacing the rubber parts as
it is this ratio that affects the platter speed.
Greg Bogantz
- Original Message -
From: Ron L'Herault lhera...@bu.edu
To: 'Antique Phonograph List' phono-l@oldcrank.org
Sent: Monday, September 03, 2012 3:03 PM
Subject: Re: [Phono-L] Anyone know an early electric phono repair man?
I'm sure someone will come in definitively on this one, but I am almost
positive, that a true idler wheel is not an influence on the speed of the
turntable. The rotational speed of the turntable is determined by the
ratio
of the motor shaft to the turntable. It might be motor shaft diameter or
circuference -or maybe it doesn't matter which you choose. I'm math
challenged. The function of the idler is to provide traction to transmit
the rotation of the motor to the turntable but not to change its speed.
Proof of this would be a stepped motor shaft driving one idler such that
changing the position to a different step changes the speed of the
turntable.
Ron L
-Original Message-
From: phono-l-boun...@oldcrank.org [mailto:phono-l-boun...@oldcrank.org]
On
Behalf Of Andrew Baron
Sent: Monday, September 03, 2012 1:03 PM
To: Antique Phonograph List
Subject: Re: [Phono-L] Anyone know an early electric phono repair man?
I would add to Ron's comment about substitute rubber for the idler wheel,
that an O-ring will indeed provide sufficient traction and makes an
attractive alternative to get your platter running smoothly and quietly
(provided that the turntable bearings / bushings are well cleaned and
properly lubricated).
As Ron noted, size (I think in this case diameter) is not critical, as
long
as it fits the steel idler disc snugly so it can't slip. However the
thickness of the O-ring or other alternative tire should be as close to
the same as it is on the original tire, or your turntable speed will be
too
fast or too slow.
Andrew
On Sep 2, 2012, at 8:54 PM, Ron L'Herault wrote:
And if it has an idler wheel between the motor's rotating shaft and
the turntable edge, its actual size is not critical. You can
substitute a rubber O ring. However, a little internet searching will
turn up places that will replace the idler's rubber with new to the same
size as original.
Ron L
-Original Message-
From: phono-l-boun...@oldcrank.org
[mailto:phono-l-boun...@oldcrank.org] On Behalf Of Andrew Baron
Sent: Sunday, September 02, 2012 8:08 PM
To: Antique Phonograph List
Subject: Re: [Phono-L] Anyone know an early electric phono repair man?
You're welcome Edward.
The rubber idler wheel can sometimes be reconditioned -softened and
surface-dressed with a chemical. If it has a notable flat spot (from
decades resting against the inside of the turntable rim under
tension), it will need to be replaced. When these get hard it
transfers all kinds of noise to the platter which then acts like a
diaphragm to magnify the noise.
The motor board, if the motor is bolted directly to it, then acts like
a sound board, further amplifying the rattle.
The original stylus might have been a metal alloy. One such was
called Osmium, which would give more plays than an ordinary steel
needle. It could also have been a jewel-tipped metal shank.
Electric Admirals from that era with no radio are pretty rare.
The repairs are pretty straightforward. Best of luck, Andrew
On Sep 2, 2012, at 5:42 PM, keeper...@aol.com wrote:
Andrew,
Thank You for taking the time to respond as you did, with all that
helpful information! I guessed aright that if the symptoms were
described, someone who knows them would indicate a prognosis. I
think that since these machines are fairly rare, and yet when working
properly play records with a lovely, iconic sound, they should be
restored. They're easier on the old records than a Victrola, also,
if you like to play them a lot, as I do. I have a great GE
phonograph, with an AM radio, that I would estimate to have been
available in the 40s, extrapolating from your description of this Admir
al.
The original stylus must be gone. I got it with a standard steel
needle in it. And yes, the garbled music was from the record. There
is no radio with this unit, it only plays records.
I'll wait and see if anyone in the area responds, but appreciate
