Thorens TD 124 restoration

Morzh

Active Member
Hi, guys,

It's been awhile since I last posted, so....

A few years ago, like maybe 6 or so, I bought me a Thorens TD124.
I knew it would need some TLC before it could take place of my Technics.

So, now that I am happily biding my time waiting for myself to be recalled while on furlough, I decided to take a stab at it.

I am not a turntable man. Have to confess.
However, I am a 1) EE with experience in absolutely any type of electronics, and 2) fairly experience tube radio restorer (electronics, no cabinets).
So I am an ignoramus only in part.

This said, I knew the turntable made attempts to turn when I bought it.
Today I took the platter off.
Immediate ovservation: the motor runs fine. Big whew! Even if it needs some lube (perhaps), it is running.
Here is the idler:



Here is the idler in 78 rpm down to 16 rpm positions.
20200428_164705.jpg
20200428_164748.jpg
20200428_164757.jpg
20200428_164806.jpg

20200428_164814.jpg



As you could see,

1) the idler has cracks
2) in the 16 rpm (photo #4) it does not touch the shaft, and then it will touch it when pushed (#5).

Also, the pushing force is not strong.

Another thing, one of the ser screws that holds the idler hub down, refuses to come out.
I have tried PBlaster, together with heatgun....no luck. I hate to drill it out.

So, what are my next steps?

Here is the bottom pictures.

20200428_170329.jpg

20200428_170333.jpg


Also:

What is a good source for idlers?
 
Good news on your motor running. Suggest servicing the motor at some point in your restoration process. I would clean the pulley surfaces, bearing well, and underneath linkages with denatured acetone. One good idler wheel source is audio silente on ebay. No affilation. Best with your project.
 
Thanks, I think I saw theirs, those are O-ring alu inum idlers, right?
How do they perform as compared to the original
 
I completely rebuilt a TD135 some years ago. The thread is here and may help you a bit. https://audiokarma.org/forums/index.php?threads/thorens-td135-refurb.447529/
Not that I’m suggesting that you do a tear down! Don’t drill out that stuck screw for now. Is it a grub screw? I’d give it regular applications of penetrating oil for some days. I doubt if you’ll ever use the 16 rpm function so don’t worry about that for now.

Do the cracks in the idler wheel affect its rotational accuracy?
 
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When you get the idler off, I recommend that you send it to Terry's Rubber Rollers for a retread. I had him do the idler on my Garrard Lab 80. It is like brand new, now.
 
The idler will not contact the 16 RPM step and the idler arm will hit the chassis because....the platter has been removed.

With the platter in place, all speeds should work. The thickness of the platter pushes the wheel away so that screw doesn't contact the chassis. That's normal for the 124.

The only thing about the idler you have to adjust is where the rim of the wheel contacts each step of the pulley (height). The flat of the tire should contact each level squarely while it's sidewall does not rub on the lower level.

Look at the 124 long enough and it will make sense.

BTW..the idler on my 124 is cracked too, but it's concentric, runs true and does not adversely affect performance.

Good luck and enjoy!
 
I completely rebuilt a TD135 some years ago. The thread is here and may help you a bit. https://audiokarma.org/forums/index.php?threads/thorens-td135-refurb.447529/
Not that I’m suggesting that you do a tear down! Don’t drill out that stuck screw for now. Is it a grub screw? I’d give it regular applications of penetrating oil for some days. I doubt if you’ll ever use the 16 rpm function so don’t worry about that for now.

Do the cracks in the idler wheel affect its rotational accuracy?


I did put some PB Blaster on.
I cannot say about the accuracy, as it does not rotate with the platter on.



The idler will not contact the 16 RPM step and the idler arm will hit the chassis because....the platter has been removed.

With the platter in place, all speeds should work. The thickness of the platter pushes the wheel away so that screw doesn't contact the chassis. That's normal for the 124.

The only thing about the idler you have to adjust is where the rim of the wheel contacts each step of the pulley (height). The flat of the tire should contact each level squarely while it's sidewall does not rub on the lower level.

Look at the 124 long enough and it will make sense.

BTW..the idler on my 124 is cracked too, but it's concentric, runs true and does not adversely affect performance.

Good luck and enjoy!


The only thing I know, the platter did not rotate, while the moror runs fine.
It is possible something there needs a lube but so far all parts on their own rotate without effort.
 
I second the recommendation for an AudioSilente idler wheel. Wish I had gotten mine sooner.

There are several possibilities for why your platter isn't turning. First is slippage at any one of several interfaces - motor/motor pulley, motor pulley/belt, belt/stepped pulley, stepped pulley/idler wheel, idler wheel/inner platter rim. A little bit of oil or misalignment at any of these places could be the culprit. I once oiled my stepped pulley from the top while doing some maintenance and then experienced speed and torque issues until I figured out the oil was oozing slowly out the top of the stepped pulley with centrifugal force and seeping down the sides, making the mating surface for the idler wheel slippery. Another possibility is your main bearing binding up. Have you oiled it? The spindle should turn smoothly and easily by hand. It's also possible for your motor to turn when not under load, but not have enough torque to do its job. If it's been sitting for a long time, I'd recommend a motor rebuild. It's easy to do and you can buy a kit from Jim Campbell for reasonable money. Finally, you might just need a new belt if yours is loose. All of the links in that chain have to be right for it to work, but if you take them one a time it's not difficult.

I had to laugh when you said you were an EE and tube guy. Neither of those things will do you any good at all here! ;) :dunno: The TD124 is almost purely mechanical, which is why a troglodyte like me can even work on it.

From the pictures, yours looks nice and clean. Take it slowly and logically and I bet you'll have it up and running in no time.
 
I see two versions of the stepped pulley
TD_9011_c.JPG

s-l400.jpg

Yours looks like the bottom version and I don't think they are interchangeable.
Can you get the idler wheel to engage with the 16RPM step if you guide it by hand? Is the sidewall of the tire rubbing against the adjacent level? All is clean?
 
I had to laugh when you said you were an EE and tube guy. Neither of those things will do you any good at all here! ;) :dunno: The TD124 is almost purely mechanical, which is why a troglodyte like me can even work on it.
.

And this is why I said:

"I am not a turntable man. Have to confess.
...........
So I am an ignoramus only in part."

If I didn't realize this turntable mostly mechanical, I wouldn't write any of that.
PS. Knowing electricity always helps where you see at least a pair of wires.
PPS. Old radios do have plenty of mechanics, some pretty complex, especially where it comes to tuning mechanisms or band switching on high end models. In fact some of it is probably as complex as this one.
Just noticing.
 
I see two versions of the stepped pulley

Yours looks like the bottom version and I don't think they are interchangeable.
Can you get the idler wheel to engage with the 16RPM step if you guide it by hand? Is the sidewall of the tire rubbing against the adjacent level? All is clean?

Heyraz, yes I can engage it by hand. It touches....barely.
The 5th photo I showed was to show exactly that.

PS. I am still applying PB Blaster. Cannot seem to move that screw. Trying to be patient.
 
Heyraz, yes I can engage it by hand. It touches....barely.
The 5th photo I showed was to show exactly that.

PS. I am still applying PB Blaster. Cannot seem to move that screw. Trying to be patient.
Honestly, if 33 and 45 work, I wouldn't risk damaging that screw.
 
Honestly, if 33 and 45 work, I wouldn't risk damaging that screw.
They don't work, though of course it might be through no fault of the idler.
I do not like it all cracked anyway.
Someone did try to get it off before as the other screw was loose.

The screw, if it comes to it, is a metric set screw and could be replaced. M2 possibly?
 
And this is why I said:

"I am not a turntable man. Have to confess.
...........
So I am an ignoramus only in part."

If I didn't realize this turntable mostly mechanical, I wouldn't write any of that.
PS. Knowing electricity always helps where you see at least a pair of wires.
PPS. Old radios do have plenty of mechanics, some pretty complex, especially where it comes to tuning mechanisms or band switching on high end models. In fact some of it is probably as complex as this one.
Just noticing.

Didn't mean to offend. Just found it ironic.
 
They don't work, though of course it might be through no fault of the idler.
I do not like it all cracked anyway.
Someone did try to get it off before as the other screw was loose.

The screw, if it comes to it, is a metric set screw and could be replaced. M2 possibly?
My guess is metric.
Worst case scenario is the previous owner damaged the threads with the wrong screw. Hopefully he just used loctite.

So you can't loosen the set screw on the collar holding down the idler wheel? You might have to remove and replace the entire rod and collar, if I understand you correctly.
 
The inside of the platter will hold the idler against the pulley when the platter is installed, don't worry about that.

I would not worry about those cracks too much at this point, since they're not on the part of the idler which actually touches anything.

What you're going to need to do is:

1. lubricate the motor
2. Lubricate the platter bearing
3. Lubricate the idler and intermediate pulley shafts
4. Replace the belt
5. Clean the outer diameter of the idler with rubber renew, or at the very least isopropyl alcohol
6. General cleaning of the whole unit inside and out

For loosening the set screw, first make sure you have a very tight fitting correct sized screwdriver, and have let it sit soaked in penetrating oil for a few days. I would be very surprised if this doesn't make it come loose.

Lots of advice about how to fix the 124, and lots of parts available. I think you will have some fun!

Good Luck
 
Thanks guys.
What also goes againt the idler is the penetraiting oil might get onto rubber...never good.
This said, the kind of money this thing costs, might as well change the tire :)
 
For loosening the set screw, first make sure you have a very tight fitting correct sized screwdriver, and have let it sit soaked in penetrating oil for a few days. I would be very surprised if this doesn't make it come loose.


Good Luck

I am not sure how to get it to "sit soaked i oil".

The sole thing I could do it add a drop while keeping it upright so gravity works it down the thread...even this is kinda....it is a spray can (yes with a straw). I soak a qtip and then try to squeeze it onto the screwhead.
 
I am not sure how to get it to "sit soaked i oil".

The sole thing I could do it add a drop while keeping it upright so gravity works it down the thread...even this is kinda....it is a spray can (yes with a straw). I soak a qtip and then try to squeeze it onto the screwhead.

Put a bit of paper towel under the screw to catch the excess, and then put a drop of oil on it every few hours over the course of a day or two, to keep it wet in oil. It won't seem like this is going to work until it does, so don't give up :)
 
Put a bit of paper towel under the screw to catch the excess, and then put a drop of oil on it every few hours over the course of a day or two, to keep it wet in oil. It won't seem like this is going to work until it does, so don't give up :)

Yep, I have it wrapped around in paper towels ( an expensive thing to do today, it is Bounty brand !!!).
And drip the PB on it.
 
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