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Thorens TD160: New belt - wobbling start

p.robustini

p.robustini

Active Member
Hi guys!
I need help or opinion on this one.
I just bought a Thorens-branded new belt for my TD160 off eBay in Germany.
It was about time I replaced the belt after 5 years...
But woth the new one installed, when the turntable starts rotating, it wobbles strongly a few seconds, then goes on rotating normally. It never happened to me before. I setup a couple of TD160s and 165s in the past. I've never seen this.
When I bought this TD160 in 2015, I instantly replaced the belt with a new Thorens-branded one. The bounce was ok, the platter was horizontal and centered. I've never experienced any issue with this deck. So I've never disassembled it in order to adjust the suspensions.
After 5 years, maybe late, I finally replaced the belt and the starting is wiggly and wobbly, everythings vibrates for a couple of seconds, then it is ok.
Maybe I replaced the belt too late and the suspensions got unbalanced because of the slack belt? Will I solve it readjusting the suspensions? Or should I give some time to the belt to wear out? But it never happend before...
The new belt is 496 mm long and 4 mm high. It measures correctly (am I wrong?) and the old one is quite longer.
I bought the old one off the German eBay, too, I think it had the correct serial on the bag, this one has none. I didn't measure the old one at the time. I just replaced it and it worked. Today it just fails to switch to 45 rpms. The new one switches correctly but wriggles at the beginning...

Advice appreciated! ;-)
Stay safe!
Pasquale
 
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Mount the platter upside down and watch the belt as it starts, is it in the correct position on the pulley.

Perhaps the belt is a little sticky and grabbing the pulley?
 
Paul-H said:
Mount the platter upside down and watch the belt as it starts, is it in the correct position on the pulley.

Perhaps the belt is a little sticky and grabbing the pulley?
Click to expand...
Done: at the start-up, I can see the "Thorens" white label on the belt going rapidly back and forth 4-5 times before finally start going ahead.
 
try it again, this time w/o the belt. see if the motor pulley (touch it if you have to) rotates back and forth a few times under slight load. If yes, the phase shift capacitor needs replacing. If no, adjust motor spindle azimuth.
 
I will a
tnsilver said:
try it again, this time w/o the belt. see if the motor pulley (touch it if you have to) rotates back and forth a few times under slight load. If yes, the phase shift capacitor needs replacing. If no, adjust motor spindle azimuth.
Click to expand...
I will as soon as I can, thanks tnsilver.
But I don't think the motor does that (no start-up problems with old belt).
I'll let you know...
 
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tnsilver said:
try it again, this time w/o the belt. see if the motor pulley (touch it if you have to) rotates back and forth a few times under slight load. If yes, the phase shift capacitor needs replacing. If no, adjust motor spindle azimuth.
Click to expand...
It doesn't... it's not the capacitor...
 
The old belt was likely stretched out with less tension. Talc can't hurt and sure is easier than goofing around with the motor azimuth adjustment, but if that doesn't work, post a frontal pic of the pulley against the subplatter.
 
The motor pulley has a clutch system where it starts slowly to first get the 7 platter moving. That slow start helps to keep your belt from wearing down from getting the heavy platter up to speed. That's normal!
 
Ilikevinyl said:
The motor pulley has a clutch system where it starts slowly to first get the 7 platter moving. That slow start helps to keep your belt from wearing down from getting the heavy platter up to speed. That's normal!
Click to expand...
Thank you!
Yes, the worrying thing is not a slow start, but a trembling of the whole suspended assembly at start-up for a couple of seconds. Something I've never experienced before...
 
IMG_8459.JPG IMG_8460.JPG
tnsilver said:
The old belt was likely stretched out with less tension. Talc can't hurt and sure is easier than goofing around with the motor azimuth adjustment, but if that doesn't work, post a frontal pic of the pulley against the subplatter.
Click to expand...
Not sure the pictures can show the real tilt if any....
(Just found out there's no talc powder at home)
 
p.robustini said:
Thank you!
Yes, the worrying thing is not a slow start, but a trembling of the whole suspended assembly at start-up for a couple of seconds. Something I've never experienced before...
Click to expand...

The sub chassis should have a piston up and down motion when you push down on the right side of the label near the last run out groove. Shouldn't have any side to side motion!
 
ddarch said:
How old is the belt? If literally a couple days, give it 10-14 days to wear in. Don't adjust anything until that amount of time passes. Also, have you checked the clutch motion is working?
Click to expand...
Thank you Dave!
The belt has just arrived. Just installed. I'll leave the turntable going for a while...
I was in fact beginning to suspect the clutch. How do I check it? The platter takes less than a round to go to a stop. I thought it meant it's working...
 
New belt:
Paul-H said:
Any chance of a video showing the issue.

And one showing it working fine with the old belt
Click to expand...
I am trying but or my videos are too large or the file extensions are not allowed.... it's becoming more annoying than the belt problem....
 
Hahaha, I know about the annoying part of trying to post videos here....I had to first create a youtube account and post my video there and then link to it. Then, I was able to post that link here and folks could view it if I remember correctly as it's been a while.

Here's something to try: wash the new belt thoroughly with soap and water, then dry with a clean cloth or paper towel by just dabbing it as you advance it through the cloth or paper towel. Once you have done that, remove the drive platter, clean the bit of oil that will be on the spindle from the well, and using very fine steel wool go around that platter (sub-platter as I believe it is called) a time or two to remove anything that may have accumulated on it. Afterwards, with a clean cloth, go around the platter a few times to make sure there is no residue from the steel wool left. Ideally, then you would drop the belt in a bag with talc powder, shake a few times and then re-install everything. PS - I have used foot powder as a last resort....it looks and acts the same as talc and provides the same function. Even without any talc, my 160 has functioned just fine so give it a try.

Good luck and health & safety over there.....
 
I wouldn't use steel wool on the spindle.
Use a fine grade synthetic pad , like 2000 grade , get em from car finishing shops.
While you are at it clean out the inside of the bearing housing with q tips and naptha. Dry and recharge with oil of choice.
To check the clutch in the pulley remove the platter and belt , hold the nylon outer part and switch on. You should be able to see the central part of the pulley rotating. If it is not you will probably feel a slight judder as the motor combats you grip.
Prob just needs a lube , couple of drops only of fine machine oil.
 
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