2. analog
  3. 1407875908

VPI SDS 45 RPM malfunction

I have a brand new SDS unit that I've used for about a month now and it's been working fine at 33 rpm, but last weekend I tried to put on a 45 rpm record and the unit malfunctioned. I was able to adjust the frequency up to 80.80 Hz, which the strobe indicated resulted in correct speed, but the voltage would flicker between 72 and 115 V for several seconds and settle at 72. It seemed the turntable was holding speed at 72, but when I put the record on and the periphery ring, the SDS kept going back and forth in frequency between 33 and 45 (up and down between approx. 60 to 80 Hz and the motor would audibly "slip" when the SDS got to 80.80 Hz and then started going back down).

Is this a matter of adjusting the unit or is the unit broken? I sent an email to VPI, but I know they are very busy so I thought in the meantime I'd ask here. Any ideas or suggestions?
actusreus

Showing 4 responses by brf

brf
1,715 posts
 
I bet you have the 300rpm motor. It sounds like you will need to change the capacitor value within the motor assembly. VPI can recommend an alternate cap value that will prevent your motor from hunting for power when running at 45rpm speed.
brf
1,715 posts
 
Try stepping up the SDS run voltage from 72v to something higher. I would start at 75v and increase the voltage until the voltage stops varying between the run and startup voltage.
brf
1,715 posts
 
Go to VPI's website and download the SDS calibration manual. In the manual are detailed instruction on how to adjust the SDS "steady state" voltage (run mode). For 45rpm, the factory default should be either 90 or 102 depending on the software version. If your SDS is dropping from 115v to 72 v after startup when in the 45rpm setting, it needs to be adjusted higher. You cannot hurt your table by trying a higher steady state voltage. I hope this corrects your problem
brf
1,715 posts
 
Contact your dealer in which you purchased he SDS, perhaps they can simply exchange the unit or loan you a SDS while yours is getting repaired. Your Dealer should make the situation rate.
More to discover