Tír Na HiFi

Right lads.... once again your help and guidance is required.

I mentioned to Derek a few weeks back that the turntable wasn't holding a steady speed. I cleaned the rubber belt with Pledge (the Roksan manual is less than subtle in its recommendation of Pledge!) and I thought things had improved a bit – this optimism was in spite of the fact that the drive spindle was clearly spinning off-centre and even had a few wobbles within that oscillating orbit.
Anyway last night it was confirmed that it really isn't playing right at all at all. Slowing down and speeding up all the time. Not good. I suppose I could limit my vinyl listening to slack-key Hawaiian lap-steel guitar tunes but that would wear thin after a few months.

What is good is that Roksan parts are easy enough to get (I think) and the motor itself just sits in place on a spindle and has, predictably enough, just 3 wires soldered to it.

See page 10 of the manual for explanatory pics.... http://www.roksan.co.uk/pdfs/XerxesSetupQ.pdf

I'm assuming it is the motor but could it be a problem with the separate PSU? The platter?

Could be:

belt
motor/pulley
main bearing
drive electronics

I'd say in rough order of likelihood.

BUT: When you say the drive spindle is clearly oscillating - do you mean the pulley on the motor?

The pulley might be loose on the motor shaft.......

Fran

Fran wrote:

BUT: When you say the drive spindle is clearly oscillating - do you mean the pulley on the motor?

I do. I don't know if the spindle that the drive wheel sits on is off-centre or what butit's not spinning 'true'.

Will give you a shout later....

Fran wrote:Will give you a shout later....

No hurry, I might be distracted by rugby goings-on today anyway.

Mmmmm I'm not so sure now. I cleaned the pulley/fly wheel and the inner platter where the belt makes contact and while the lack of consistent speed is still a clear issue I'm now not confident (if I ever was) that it's the motor. I suppose a spare belt is no harm to have although the current one looks fine if a bit flaccid (who am I to point and laugh?).

When you say "flaccid" - that may well be the cause of your problem.

I see from the service manual that the motor is mounted on a kind of spring loaded mech - that wouldn'tbe jammed or something causing the belt to be looser than it should?

I know ages back when I was using the ariston deck it had wow that I couldn't figure out. I cleaned the belt with some white spirits, then allowed it to dry, then rubbed in a bit of talc. Shook it all out so it was clean and dry and it worked wonders.

I suppose try a new belt (once its not crazy money).

Fran

Fran wrote:
I know ages back when I was using the ariston deck it had wow that I couldn't figure out. I cleaned the belt with some white spirits, then allowed it to dry, then rubbed in a bit of talc. Shook it all out so it was clean and dry and it worked wonders.

I suppose try a new belt (once its not crazy money).

Fran

Well I've done the belt cleaning (with Pledge as recommended!) but I didn't try the talc. As I say buying a belt is no biggie so I might just do that, I get the impression even genuine Roksan parts aren't that dear.

Hello Ivor

Couple of questions and suggestions if you haven't ordered the belt - which would be where I'd lay my bets, that or Big Zeb for the 3:20 at Cheltenham - yet and the problem still persists.

How old is the Belt? I'd be looking to change every 2 to 3 years even with light use. Your motor and Main bearings like constant regular forces. Once a belt starts to stretch unevenly the force it puts on the bearings starts pulsing and this accelerates wear.

With the belt off, if you run the motor does it spin smoothly? I'm not familiar with TT and there will be a certain degree running noise but does it seem excessive to you? Likewise with the main bearing when you hand spin the platter? Watch the platter when its close to stopping, is it still spinning and slowing down evenly.

Finally is the problem more apparent when you first start up, once the belt warms up the problem may ease slightly if it's the culprit.

Good Luck

Mike

I'll fire her up and try those checks later Mike thanks. The belt ain't new! I've had the TT a few years (light enough use) and I'd say it was around a while before I got it. Visually ithe belt looks fine but it does seem a little slack to me.