Record player runs slow - Motor problem? - UK Vintage Radio Repair and Restoration Discussion Forum

Vakito227 · 27th May 2016, 10:53 pm

I was recently given a fresh new idler wheel from Alan SP15 which was a very kind gesture of him. After giving the wheel, spindle and inside of the platter a good clean out and checking for any tight spots in the mechanism, I put everything back together and gave it a test. The turntable now has more torque and the juddering has gone completely. only problem is the speed is about 5% slower than what it should, can't be anything to do with the friction drive ratios and it can't be caused by the idler slipping since it now grips better and resists force applied to it. The problem must lie in the motor, but here comes the weird bit, when I plug the record player into my modified sinewave inverter, it plays at the correct speed.

Perhaps the motor was always like this because before I got this new idler, I had to cover the motor spindle with a layer of duct tape to make it grip the rubber wheel, even though the tape was thin, it would have been enough to make a significant difference to the speed due to the tiny diameters on the spindle.

The inverter is a bit of a crappy one and pumps out 50Hz with 3Hz give or take so maybe the inverter gives 2 or 3 more cycles per second adding an extra 150 or so RPM to the motor which coincidentally brings it up to the correct speed.

I have 4 options really:

1. Reapply duct tape to the spindle
2. Replace the motor
3. Machine a new spindle with slightly larger diameters
4. Use the inverter to power the record player from now on

To be honest I'd prefer to stick with option 4 at present although this brings up a new question that you may be able to answer, does the modified sine wave inverter damage the electronics in my record player? I'm sure some of you will know better than me but I'm guessing that it's harmless since the only AC components is the induction motor that powers the turntable and the valve heaters, everything else goes through a rectifier. I understand not to use it on a radio since most if not all its components run on AC although the only differences I have noticed by running the record player on the inverter are a more intense buzzing noise on low volumes that disappear when turned up and the motor spinning faster.

I have some plans for the inverter over the next few weekends and I'll be posting the entire project on here if I ever get it finished.

Thanks
- Peter

jonnybear · 27th May 2016, 11:13 pm

Are you asking for information on the Technics SP15 as this deck appears to be a quartz locked direct drive turntable. IF it is a BSR or Garrard you could have a 60 cycle motor. this has been brought up before, if this is the case you may get away with a piece if thin shrink sleeve.
John

Chiltern · 27th May 2016, 11:42 pm

Vakito has a Garrard 209 changer.

Alan

Vakito227 · 27th May 2016, 11:57 pm

As Alan said, it's a Garrard 209. Should have specified before, my fault. As for the motor, I'm quite sure it's 50Hz since I bought it off the original owner from North Wales

leslie5555 · 28th May 2016, 12:10 am

I had the same problem with a Garrard 210. I checked the diameters of the spindle against another I had and they were all about 0.2mm smaller, so I made a new one at work with the correct diameters and it now plays the correct speed. Hope that helps.

Vakito227 · 28th May 2016, 11:41 am

I think that would be a good idea also.

27th May 2016, 10:53 pm	#1
Vakito227 Hexode Join Date: Apr 2016 Location: Yeadon, West Yorkshire, UK. Posts: 251	Record player runs slow - Motor problem? I was recently given a fresh new idler wheel from Alan SP15 which was a very kind gesture of him. After giving the wheel, spindle and inside of the platter a good clean out and checking for any tight spots in the mechanism, I put everything back together and gave it a test. The turntable now has more torque and the juddering has gone completely. only problem is the speed is about 5% slower than what it should, can't be anything to do with the friction drive ratios and it can't be caused by the idler slipping since it now grips better and resists force applied to it. The problem must lie in the motor, but here comes the weird bit, when I plug the record player into my modified sinewave inverter, it plays at the correct speed. Perhaps the motor was always like this because before I got this new idler, I had to cover the motor spindle with a layer of duct tape to make it grip the rubber wheel, even though the tape was thin, it would have been enough to make a significant difference to the speed due to the tiny diameters on the spindle. The inverter is a bit of a crappy one and pumps out 50Hz with 3Hz give or take so maybe the inverter gives 2 or 3 more cycles per second adding an extra 150 or so RPM to the motor which coincidentally brings it up to the correct speed. I have 4 options really: 1. Reapply duct tape to the spindle 2. Replace the motor 3. Machine a new spindle with slightly larger diameters 4. Use the inverter to power the record player from now on To be honest I'd prefer to stick with option 4 at present although this brings up a new question that you may be able to answer, does the modified sine wave inverter damage the electronics in my record player? I'm sure some of you will know better than me but I'm guessing that it's harmless since the only AC components is the induction motor that powers the turntable and the valve heaters, everything else goes through a rectifier. I understand not to use it on a radio since most if not all its components run on AC although the only differences I have noticed by running the record player on the inverter are a more intense buzzing noise on low volumes that disappear when turned up and the motor spinning faster. I have some plans for the inverter over the next few weekends and I'll be posting the entire project on here if I ever get it finished. Thanks - Peter

27th May 2016, 11:13 pm	#2
jonnybear Octode Join Date: Nov 2010 Location: Cullompton, Devon, UK. Posts: 1,435	Re: Record player runs slow - Motor problem? Are you asking for information on the Technics SP15 as this deck appears to be a quartz locked direct drive turntable. IF it is a BSR or Garrard you could have a 60 cycle motor. this has been brought up before, if this is the case you may get away with a piece if thin shrink sleeve. John

27th May 2016, 11:42 pm	#3
Chiltern Heptode Join Date: Dec 2008 Location: Somerset, UK. Posts: 555	Re: Record player runs slow - Motor problem? Vakito has a Garrard 209 changer. Alan

27th May 2016, 11:57 pm	#4
Vakito227 Hexode Join Date: Apr 2016 Location: Yeadon, West Yorkshire, UK. Posts: 251	Re: Record player runs slow - Motor problem? As Alan said, it's a Garrard 209. Should have specified before, my fault. As for the motor, I'm quite sure it's 50Hz since I bought it off the original owner from North Wales

28th May 2016, 12:10 am	#5
leslie5555 Heptode Join Date: May 2015 Location: Reading, Berkshire, UK. Posts: 692	Re: Record player runs slow - Motor problem? I had the same problem with a Garrard 210. I checked the diameters of the spindle against another I had and they were all about 0.2mm smaller, so I made a new one at work with the correct diameters and it now plays the correct speed. Hope that helps.

28th May 2016, 11:41 am	#6
Vakito227 Hexode Join Date: Apr 2016 Location: Yeadon, West Yorkshire, UK. Posts: 251	Re: Record player runs slow - Motor problem? I think that would be a good idea also.