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VPI Scout - slow speed , help ?

Hi

I've recently purchased a KAB speed strobe which has indicated that my Scout is running very slow (notches moving counter clockwise); over 100 notches in 60 seconds.

I have the newer black belt with unknown time on it; I've cleaned the belt, motor grooves and platter grooves. I get power from a dedicated 15amp plug, through an Audience AR-6 conditioner and stock power cord to the motor. I've tried using different notches on the upgraded 300 rpm motor pulley, with little effect.

I suppose the cheapest experiment is to buy a new belt, and lube the spindle bearing (for which I'll have to purchase oil) and see if that changes things. Short of buying the VPI SDS, are there any other actions which may help here for little money? Perhaps a used Variac would essentially do what the SDS does?

Your constructive feedback is appreciated.

Regards,

Bryn
bshapperd
hifihvn
943 posts
 
Also, the P3 Kilowatt can be left plugged in, and you could watch the Volts or cycles readout. The cycles most likely will stay between 59.99 to 60.00 cycles. That's fine. If you have lights flickering, bulbs burning out, call your electric company, or electrician to get there quickly. That would be in case they left a loose connection somewhere. Not common, but possible, since new work was just done.
mofimadness's avatar
mofimadness
5,725 posts
 
Make sure the pulley is tight against the motor shaft. It has a set screw I think. Could be that the pulley is slipping a little bit.
hifihvn
943 posts
 
Oops, it's the P3 Kill A Watt. [http://www.homedepot.com/h_d1/N-5yc1v/R-202196386/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053]
markd51's avatar
markd51
765 posts
 
It won't so much be voltage that will cause your problems, (if it is a electric source problem) it will be line frequency varying.

While the VPI SDS can vary, and ramp down voltage, the Platter speed is set by varying the output frequency of the SDS.

While not impossible, it is rare that line frequency will vary that greatly to cause you a considerable slow condition one time, and then run fast another.

And I sort of doubt your KAB Strobe Disc is at fault.

I assume your Scout uses the newer style Inverted Bearing.
These are to be lubricated with grease, not oil. A simple Lithium Grease will be suitable.

I suspect your problem to be your conditioner. Plug direct to the wall, not the power conditioner, and then take a measurement with the Disc. If you have the stepped Motor Pulley (the one with a number of ridges on it), you can then set the belt upon the ridge-groove of choice to get as close to 33-1/3rpm as you can.
Hope this helps. Mark
bshapperd OP
84 posts
 
Ok, the platter is consistently measuring fast, now. I've taken measurements with the motor plugged into: a different circuit; wall receptacle of the dedicated 15amp; the power conditioner, all with the same results. I've tried using different steps on the pulley with no noticeable change. I've tightened up the set-screw on the pulley (which was loose) and used a 45 lp on the platter to replicate stylus drag.

I'll try measuring the speed of the platter at different times of the day, but as others have mentioned, voltage should not effect the platter speed?

Ok, new thread " VPI Scout running FAST, help?"

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