[Jukebox-list] Rockola Tempo2 Speed

[John Robertson]

Bob Ellingson wrote:
> At 02:52 AM 11/5/2007 -0500, you wrote:
>   
>> Bill, keep it simple. If the tape increased your speed to the correct
>> speed, that tells you that the ratio is slightly off between either the
>> motor end piece which engages to the idler wheel, or the idler wheel is
>> slightly too small. 
>>     
>
> The size of the idler wheel will not matter!  If you calculate
> the ratio of the idler wheel to the motor spindle, and then 
> the ratio of the turntable to the idler, you will see that it
> cancels out:
>
>        Spindle         Idler            Spindle
>       --------   X   ----------   =    ---------   =  Speed
>         Idler         Turntable         Turntable
>
> The problem has to be friction, slippage, or mis-match
> of the spindle-to-turntable size.  This isn't in a 50 Hz
> area, is it?  Maybe the spring that enlarges the spindle
> for use in foreign areas has fallen off?
>
> --Bob
> =======================================================================
> Bob Ellingson					bobe at halted.com
> Halted Specialties Co., Inc.			http://www.halted.com
> 3500 Ryder St.					(408) 732-1573
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>
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>   
The only turntable drive wheels where there is a problem with ratios are 
the two step idlers that were used in the 50's. There they divided the 
motor speed by the ratio of the two wheels on the idler as well as the 
ratio between the turntable and the motor spindle. As I recall the 
Wurlitzer 1250 through 1650 all used this, as did Rockolas up to the 
early 60s (or is it the late 50s?) the 1454 for one used the two step idler.

However by the time of the Tempo they only used a single wheel idler. So 
then lack of enough friction is the only thing you have to sort out when 
the speed is low - assuming the turntable motor and the turntable main 
bearing are both running freely. A few drops of nail polish remover will 
revitalize those idlers - use the non-acetone version though.

John :-#)#

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