Re: My M102 _rattles_

[Ted Thompson <tthompsn@mail.bcpl.lib.md.us>]

D J Neal wrote:
> 
> Vince Ryan has a squeaky M-100, but mine rattles as the startup motor tries
> to engage the main generator shaft. Sometimes it can take a good few attemps
> to start the organ.
> 
> Do experience people think its a mechanical failure (i.e. do I need a new
> start motor, or even a new generator(!) ...?) or is it lack of lubrication?
> The oil threads all seem to be intact. ... can I give an extra dose of oil
> down there among the cogs?
> 
> TIA
> -------------------------------------------------
> David J Neal,
> 16 Ffordd Gwynedd,
> Wrexham,
> LL11 2TF,
> UK                           david@neal.u-net.com
> -------------------------------------------------


The run switch has two sets of contacts, one set for on and one for off, 
this is not quite a double throw swith in the conventional sense.  In the 
one position power is supplied to the syncronous (sp?) motor, amplifier, 
etc.  But in the off position it shorts out a series resistor in the 
wiring to the start motor.  If this set of contacts fails, or (as on 
later model B3's et. al. ) there is a little jumper between the run and 
start switches that has broken, the start motor will do just what you 
described.  The purpose of the resistor/run switch circuit is to aid in 
the transfer of the load to the sync. motor by reducing the torque and 
speed of the start motor.  And if it isn't shorted during the initial 
power up of the start motor, the start motor won't have the "power" or 
magnetic field to "pull in".


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