Thorens TD280 - motor problem

[HesNot]

Hello - hoping I can get some help from the knowledgeable members here (longtime lurker, first time poster) regarding my Thorens TD280 (mk I).

I haven't been spinning much vinyl due to the belt slipping - and I hadn't gotten around to getting a replacement. So I sourced a new belt - cleaned the pulley and sub platter well - and installed the new belt. The belt is no longer slipping - however when I start it up it will not spin up to full speed on 33 or 45. both with the platter in place, as well as without the platter - the motor assembly is clicking and stuttering. Basically it's slipping, but the 280 does not have a slip clutch mechanism so the motor itself is slipping. If I give the platter a little assist it will spin up, stop clicking and seemingly run fine.

I've lubricated the sub platter and it spins freely. I've blown compressed air around all components and lubricated what I can access of the motor assembly but it appears to be a closed unit.

The last time I had used it I did not have this issue so I'm not sure what has gone awry other than a period of disuse (several years).

Replacement motors such as I've been able to find (an italian site listed here actually) are very very expensive - $170 ish USD which is not worth spending when I can add a bit more and get something else (used Rega for example).

So - any suggestions on things to try that I haven't? I've read the Thorens overhaul guide but it is mostly difficult to follow and I think targeted at models other than the TD 280 since I cannot find many of the items referenced.

Is the pulley removable from the motor spindle? If so maybe some deoxit down the spindle?

I fear the motor is shot - that one or more of the brushs is bad for example such that under load it can't overcome the short - but once spinning fully it can turn past the bad spot.

All input is appreciated - if it is shot any suggestions for a replacement in the $200-$300 range? I am using a Shure V15 VMR which I like quite a bit..

 

[muovimies]

Forget about deoxit down the spindle....

Do you still have the old belt, does it spin up to speed with that? It might just that the new belt is too tight.

Does it change anything / help, if you gently push the motor axle towards the platter spindle, or further away from it - this will help you determine if too high or low belt tension has something to do with it (cover your finger with a piece of cloth to lessen friction so the motor can still turn).

 

[HesNot]

I do have the old belt - it does not spin up with that on as it slips off the sub platter assembly. I'll try the gentle movement of the motor spindle.

Tinkered with it some more last night - still clicking - on 45 it will spin up and judder a bit but then get to speed without the motor sticking. It seems to power past the stutter - but still no luck on 33.

 

[lini]

HN: Did you already check the check the electronics? The 280s are old enough now to already show problems with aged elcaps. Iirc besides the bigger one right after the rectifier there are only four more elcaps on the board, so it would seem wisest to just replace all five...

Greetings from Munich!

Manfred / lini

 

[HesNot]

HN: Did you already check the check the electronics? The 280s are old enough now to already show problems with aged elcaps. Iirc besides the bigger one right after the rectifier there are only four more elcaps on the board, so it would seem wisest to just replace all five...

Greetings from Munich!

Manfred / lini

I've not checked the electronics - really just tinkered with mechanical components. This is an interesting take - I'll have to take it to someone I think for diagnosis then - I'm only so so with a soldering iron and not knowledgeable enough to test the capacitors.

 

[lini]

HN: Actually I'd suggest to replace 'em all in any case. Because five new elcaps won't cost that much, and it would seem a good opportunity to do that while you're working on the Thorens anyway, and then you can rest assured that that front is cleared for another 25 years...

Oh, and there should be a table with the voltages at the various test points for several operating states in the service manual, iirc, which might be helpful for problem diagnosis...

Greetings from Munich!

Manfred / lini

 

[StephenS]

I'm lost in the forum posts. Can anyone find the post where someone suggests replacing caps and diodes to increase motor voltage from 10v to 13v? I'm interested in trying this to get my TD280 to start without having to hand start the platter. Thanks al.

Regards,

Steve

 

[lini]

Steve: I'd assume you're referring to this thread: http://audiokarma.org/forums/index.php?threads/thorens-td-280-start-up-problem.785621/

Given that you've replied to that thread and that this reply had been your only posting so far (before you've started this thread), the easiest way to find it would have been to use the "your content" option in the menu, that pops up, when you move the mouse pointer onto your name at the top of the page (i.e. the same menu that you'd also use to log yourself out) - but alternatively you could also use the "postings" tab on your profile page.

Greetings from Munich!

Manfred / lini

 

[Sandrews]

I had a problem with a TD280 MkII where the motor would vibrate but not spin. Tried replacing the two LM324 ICs, they were conveniently in sockets. This fixed the problem. I thought it might have been corrosion on the pins and unplugging and replugging the ICs may have fixed it, but swapping them around proved that one had failed. Just an avenue to explore if mechanical maintenance and electrolytic cap replacement prove ineffective.