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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

Showing 7 responses by bshapperd

bshapperd OP
84 posts
 
Well, I think I've just discovered some major power fluctuations in my 'hood!

With the motor positioned correctly, I tried Elizabeth's trick; I counted 103 1/3rd rotations in 3 minutes. I tried the KAB again and it was reading fast (????)!

My assumption now would be that the power to my home fluctuates greatly throughout the day? We have a new 200 amp panel, new wiring and a dedicated line to the TT. How do I check voltage from the wall socket; can I do this with a multimeter?

B
bshapperd OP
84 posts
 
The 300 rpm motor came with the table; it does have have a different value capacitor than the 600 rpm motor (also included with the table purchase).

I'm hoping VPI can help me from here on out.

Thanks!
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?"

What now?
bshapperd OP
84 posts
 
I'll try boiling the belt; I'm sure to get raised eyebrows from my wife! I'll also try installing the original 600rpm motor and re-measure the speed.

For skeptics of the KAB strobe disc, the supplied VPI strobe measures the same.

B
bshapperd OP
84 posts
 
Ok, for those of you following this thread: I've just switched out the 300rpm motor for the original 600 rpm model, and the speed is almost perfect! There must be some issue with the capacitor (as someone previously mentioned), or perhaps the pulley, or motor itself.

I'll contact VPI for further diagnoses.

Thanks for all of your suggestions!

Regards,

Bryn
bshapperd OP
84 posts
 
I thought I would update this post for future reference. Initially, the pulley was loose on the motor drive-shaft which caused the pulley to slip, resulting in slow platter speed. After tightening the pulley's set-screws, the platter ran fast.

At this point I contacted VPI who suggested I send in the existing 300 RPM pulley, as it was probably for a 12" platter, not the 11 1/2" acrylic, Scout platter.

So, I've just installed the new pulley, sent from VPI, and everything is perfect; solid speed, good sound.

Thanks for your efforts.
bshapperd OP
84 posts
 
Is it possible that the belt has stretched? Take the belt off, boil it in water, then reinstall and try again. VPI tip is to put the belt into a samall bag with a little bit of talc powder, give it a shake, then reinstall the belt; this powdered belt helps to negate any slippage between the belt and platter.

You say the pulley is tight; a loose pulley was my first thought? Take off the platter and confirm the thrust bearing is adequately greased ( I'm reaching here).

B
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