Repairing Thorens TD125 MKII

h00kem

New Member
HI folks - new to the form and to Thorens TTs. Have a TD 125 MKII I purchased broken and want to repair. Motor pulses but does not turn. From reading threads on the forum I think the problem may be one or two things. First, the capacitors - specifically the two 1000mF capacitors on the main board, but if I'm going to replace those two then I might as well do all of them on the board.

Question #1 - I'm having a hard time finding the right capacitors. Have looked at Mouser and can't find what I believe to be the right ones. Any suggestion on sourcing the capacitors?

Second problem. The board has a small light bulb on it. The two issues with the light. First, unlike the reference pic I have found that shows a "strobe" light on the front face of the board, mine has a small bulb soldered to the back of the board. Looks like a prior owner may have done it. The bulb does not look like the one in the reference picture. Second, when power is applied the bulb does not light up.

Question #2 - Does it matter if the bulb is on the face or back of the board? Anyone know the correct type and a source for the bulb?

Thanks for reading my post and for any assistance you can offer.

Kevin
 
I have used these 50V/1000uF Nichicons (p/n TVX1H102MCD) to replace the power supply caps - which you should really replace.
The stock German golden caps were excellent at the time but are known to cause issues and instability at their end-of-life.
There's seldom a real need to replace the stock film capacitors - but have them checked out and replace if needed.
That light bulb on the PCB has nothing to do with the neon strobe lamp or even with illumination.
It's a 6V/20mA incandescent light bulb that serves as a temperature compensator for the Wien's bridge and it is crucial that you keep it's specs.
You may find it very hard to source a replacement for the bulb. I've used T5.5 telephone slide lamps in the past after custom slicing their leads to
fit the lamp housing on the Thorens. The eBay source I used at the time does not sell them any more but if you google "20mA 6V T5.5 lamp" you
might find a new source.

Follow the service manual to the letter and set the respective trimmers for the voltages it mentions for each of the speeds, at each of the
motor windings on the red and blue wires to the motor (rt/bl).

You can use my parts list if you need reference to other parts:

4eK9GRG.png
 
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Hi Tom,

Thanks so much for the great information. Most helpful! One last question regarding the lamp. Do you think it matters whether it is mounted on the front side of the board versus the back? Mine is on the back, but it appears to me that perhaps this was done by another owner.

Best,
Kevin
 
Neah, it doesn't matter. It's stock location is on the inside with the other components. Changing it may interfere with the bottom cover of that turntable. Not too much space there.
 
Thanks. I am not sure why a prior owner might have moved it to the back of the board from presumably the front. Best, Kevin
 
Ha! I'll bet it was a let-down. By the way, I did find the lamps on eBay from one seller and there are more if you need them.
 
I don't have a socket on the board. The leads coming out of the bulb are soldered onto mine ( see img850) and note mid board to the left. There is no bulb or socket on top of the board (img2291). Strange. But as long the existing one on the board is a 6v/20mA I can certainly improvise. I remove the existing one, test and reattach if its working. If not, I'll give the one you suggest a try. In any event, at least I now have a backup plan. I did find and order the capacitors you recommend. I guess even though the originals are 25V using a
50V is fine? Thanks again for your help !IMG_0850.JPG IMG_2291.JPG
 
Maybe I’m wrong, but it looks that one of the mustard yellow capacitors in your pic has a broken lead.
 
Yes, using 50V is fine. The stock PCB has a socket for the lamp. Maybe the lack of it was why it was positioned on the other side of the board. You could order a socket for the T5.5 or just do the same. I can't spot a fault on any cap in the picture but you could sure do with replacing the golden PS electrolytics. I don't like the scorch marks under the transistors near the op-amps. You need to make sure the transistors are intact and don't short and that the resistors hold their spec'd value.
 
Hi Tom,

I'm replacing caps using the parts list you provided (thanks!). Question, for C11, do you mean solder in two .10 caps in place of the one .20 cap in the original?

Thanks,
Kevin
 
Yup, if you solder two 0.1uF caps in parallel, you get 0.2uF capacitance.
Unless you can source a single good 0.2uF cap with at least 160VDC rating.

Notice this configuration. With the LM741 (8 pin) op-amps, instead of the stock LM709 (16 pin) you need to give up the
R/C network around the op-amps. The parts in red squares go out, the new op-amps are in green.

Ka3Vgwy.jpg
 
Yup, if you solder two 0.1uF caps in parallel, you get 0.2uF capacitance.
Unless you can source a single good 0.2uF cap with at least 160VDC rating.

Notice this configuration. With the LM741 (8 pin) op-amps, instead of the stock LM709 (16 pin) you need to give up the
R/C network around the op-amps. The parts in red squares go out, the new op-amps are in green.

Ka3Vgwy.jpg
Very cool. Thanks for the help. I'm getting there! Kevin
 
I am reading this thread again and again for the whole lot of useful information it contains and I just want to express my gratitude to tnsilver.
This information does apply to some TD160 models apparently (mine in this instance)
Thank you
 
Gentlemen. Not sure if this is the right place to ask this, but I’ve just got my hands on my first turntable ever. It’s an extremely well kept and sparingly used Thorens TD125 MKii.

I’ve had it serviced, it had a Shure M75 stylus attached to it. The technician says it’s fine, but since I have no TT experiences to compare with, I’m sure it’s lost it’s glory since 1980.

So a few stupid questions if I may...

1- Does this Thorens model have a MM or MC pickup?
2- Can a MM setup be replaced by a MC setup?
3- If I insist on replacing the cartridge and stylus both, what are your recommendations for both please, staying in the vicinity of 200$.
4- Will I need to replace the super cool stock Thorens headshell?

Thanks in advance.
 
Gentlemen. Not sure if this is the right place to ask this, but I’ve just got my hands on my first turntable ever. It’s an extremely well kept and sparingly used Thorens TD125 MKii.

I’ve had it serviced, it had a Shure M75 stylus attached to it. The technician says it’s fine, but since I have no TT experiences to compare with, I’m sure it’s lost it’s glory since 1980.

So a few stupid questions if I may...

1- Does this Thorens model have a MM or MC pickup?
2- Can a MM setup be replaced by a MC setup?
3- If I insist on replacing the cartridge and stylus both, what are your recommendations for both please, staying in the vicinity of 200$.
4- Will I need to replace the super cool stock Thorens headshell?

Thanks in advance.

1) The cartridge you choose is the pickup and determineds MM vs. MC. The TT is agnostic as to the type of cartridge (MM vs MC) as it has no built in phono amp. I run a Moving Magnet cartridge in my table. You not likely to find a Moving Coil (MC) in that price range.
2) Yes, but you will want to make sure to have the proper phone amp in place to support the cartridge of your choice. If the amp you are using has a phono imput its probably MM - some can be switched to MC so be sure to check if is supports one or both. If it does not have a phono input you will need to buy one for the type of cartridge you select (MM vs. MC - some support both with a switch).
3) Everyone has an opinion, but in that price range I would probably choose a low level moving magnet (MM) Grado, Ortofon or Shure cartridge - ask your local stereo store what they would recommend.
4) Probably not as the original headshell is somewhat universal and can take a variety of cartridges. Again, tell the retailer what headshell you are using but I am guessing it won't be an issue.

Hope this helps
 
Just one additional information on point 3)
The stylus is normally the part that wears out. Depending on the exact type of cartridge you may have more than one option; for example, for a shure M75 ED, you can have an elliptical or a JICO SAS (some form optimized for the contact). And that alone can make a difference.
I would just give the M75 a chance.
Hope I did not add too much confusion
 
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