When my turntable is turned on and off, there is a loud crackling sound from the horn. I replaced the capacitor 10NF connected in parallel to the switch. It seems that there has been no improvement. Experienced people, please tell me where the malfunction occurred? I have two TD124, and the other one won't make any noise.
One suggestion.
You are working with the AC mains, so follow all safety precautions and unplug the thing when you are working on it. Insulate all connections you are working on in tests and certainly once you're done.
Install an MOV rated for well over your line voltage, across the line and past the switch (motor side). It would be nice to have a fuse before it (line side) in case it sees a big spike and shorts. The MOV would help save your equipment from damage.
The crackling is probably caused by the switch arcing. Try replacing the switch with any other kind of switch rated for the current and voltage just to test. If that noise is gone, you have a bad switch. If you had a snap sound, that is likely inductive kick from the motor winding and the MOV should stop that. The MOV will extend the life of a power switch.
-Chris
You are working with the AC mains, so follow all safety precautions and unplug the thing when you are working on it. Insulate all connections you are working on in tests and certainly once you're done.
Install an MOV rated for well over your line voltage, across the line and past the switch (motor side). It would be nice to have a fuse before it (line side) in case it sees a big spike and shorts. The MOV would help save your equipment from damage.
The crackling is probably caused by the switch arcing. Try replacing the switch with any other kind of switch rated for the current and voltage just to test. If that noise is gone, you have a bad switch. If you had a snap sound, that is likely inductive kick from the motor winding and the MOV should stop that. The MOV will extend the life of a power switch.
-Chris
Do you have the microswitch or the large open contact switch? Also is the ground wire between the motor and chassis connected?
What sort of capacitor did you use for replacement?
Is the tone arm grounded through its own ground cable to the pre-amp? Chassis grounded or not?
Some pictures of the wiring differences between the two tables would help me to possibly understand where the problem lies.
What is the strobe light source? It does not look like the stock neon lamp. (If not disconnect it and see if the pop goes away.)
I have a 124MKII and there are no audible pops when I turn the motor on and off. No chassis GND, but the arm is grounded to the pre-amp.
What sort of capacitor did you use for replacement?
Is the tone arm grounded through its own ground cable to the pre-amp? Chassis grounded or not?
Some pictures of the wiring differences between the two tables would help me to possibly understand where the problem lies.
What is the strobe light source? It does not look like the stock neon lamp. (If not disconnect it and see if the pop goes away.)
I have a 124MKII and there are no audible pops when I turn the motor on and off. No chassis GND, but the arm is grounded to the pre-amp.
Thank you for your reply. Based on your prompt, I checked again and found that I made a foolish mistake. I actually installed a 1NF capacitor.
I have reinstalled a capacitor with a capacity of 6N8, and the switch has almost no noise. I took pictures.
Actually, I have added another 6N2 capacitor now, with a total capacity of 12N4. The noise inside the horn can be ignored when turning on and off the turntable. I am very satisfied.
Once again, I would like to express my gratitude to those who have helped me. My next plan is to make a base with a transparent lid.
Additionally, the light bulb I am using is a regular LED light.
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Thank you for your reply. I have resolved the issue and installed the wrong capacitor.
Looking good. I would recommend tinting the LED lamp with orange nail polish or similar. 🙂
When TD124 was first purchased, there was no clutch, no spindle, and no rotating plate. I purchased or DIY the parts bit by bit. Today I made a clutch, and the final result was better than I had imagined. It was laser cut using a 1MM stainless steel plate, with the same thickness as the original. I plan to make another 1.5mm piece to try, because the brass plate I used is very heavy, and separating the copper plate is a bit difficult. The 1mm stainless steel plate is a bit soft.
I followed Anatech's suggestion to replace the LED with beige, which is indeed more attractive. I opened the LED light bulb and found a capacitor inside. I removed the capacitor. In the absence of capacitors, the LED appears to be flashing, but the dial appears clearer. It's a good thing.
If anyone needs this drawing, I can publish the CAD file here. I spent a lot of time drawing this blueprint.
I followed Anatech's suggestion to replace the LED with beige, which is indeed more attractive. I opened the LED light bulb and found a capacitor inside. I removed the capacitor. In the absence of capacitors, the LED appears to be flashing, but the dial appears clearer. It's a good thing.
If anyone needs this drawing, I can publish the CAD file here. I spent a lot of time drawing this blueprint.
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Very nice. Sharing is what it's all about here. 🙂
I see that you removed the platter from the spindle.
Here is shown how to adjust the platter: https://www.soundfountain.com/amb/td124page.html
in case you want to do a perfect job.
Hugo
I see that you removed the platter from the spindle.
Here is shown how to adjust the platter: https://www.soundfountain.com/amb/td124page.html
in case you want to do a perfect job.
Hugo
Hello All,
I am new to diyAudio and glad to find this informative thread!
Have been looking into slowing down the rpm of my Thorens TD-124 which is off by ~3% (34.2rpm) when set to minimum fine speed control (knob fully CCW). The magnet is as close to the stepped pulley as possible also. This unit is a very early model and after my initial work on it to make functional, been professionally restored and upgraded so a bit disappointed that there is still an rpm issue.
My question is: has there been any successful experience with slowing down the rpm using a stronger magnet (or even doubling up the magnet, though this may need a longer screw)? Any other angles I should be looking at?
All thought on this or related welcome!
Thank you,
Henry
I am new to diyAudio and glad to find this informative thread!
Have been looking into slowing down the rpm of my Thorens TD-124 which is off by ~3% (34.2rpm) when set to minimum fine speed control (knob fully CCW). The magnet is as close to the stepped pulley as possible also. This unit is a very early model and after my initial work on it to make functional, been professionally restored and upgraded so a bit disappointed that there is still an rpm issue.
My question is: has there been any successful experience with slowing down the rpm using a stronger magnet (or even doubling up the magnet, though this may need a longer screw)? Any other angles I should be looking at?
All thought on this or related welcome!
Thank you,
Henry
Reducing line voltage to levels found in its heyday has proven effective.
Correct weight non detergent traditional 20 - 22 sae weight oil used for lubrication? The lubricant used is important.
Make sure you have the right belt, get one from Hanze Hi-Fi in Holland if there is any question, there are a couple of other good ones but I have not messed with mine for a long time and no longer remember. (The belt should be quite thin, IIRC somewhere around 35 - 40mils) I can dig one out at some point and measure it.
Motor voltage setting? If 100 - 125V, and your line voltage is at the top of the range you can try the 125V - 150V tap, noting that I have not had good results doing so.
Are you sure the motor pulley is oriented the right way? I have seen more than one instance where the pulley was oriented the wrong way and the brake magnet was as close as possible to the intermediate pulley in order to slow it down. Smaller diameter is used for 60Hz.
The other thing to do is perhaps find someone who can remagnetize the brake magnet if needed.
There should be absolutely no need to modify the table from its original design to fix this problem, over 100K were built and when new they all ran on speed.
Restoring the TD-124 is really something of an art, and there are only a few people I would trust to do it, these would be Hanze Hi-Fi, STS Turntables or Woodsong Audio. I restored about a dozen of them, but these guys are all better at it than I ever was.
Correct weight non detergent traditional 20 - 22 sae weight oil used for lubrication? The lubricant used is important.
Make sure you have the right belt, get one from Hanze Hi-Fi in Holland if there is any question, there are a couple of other good ones but I have not messed with mine for a long time and no longer remember. (The belt should be quite thin, IIRC somewhere around 35 - 40mils) I can dig one out at some point and measure it.
Motor voltage setting? If 100 - 125V, and your line voltage is at the top of the range you can try the 125V - 150V tap, noting that I have not had good results doing so.
Are you sure the motor pulley is oriented the right way? I have seen more than one instance where the pulley was oriented the wrong way and the brake magnet was as close as possible to the intermediate pulley in order to slow it down. Smaller diameter is used for 60Hz.
The other thing to do is perhaps find someone who can remagnetize the brake magnet if needed.
There should be absolutely no need to modify the table from its original design to fix this problem, over 100K were built and when new they all ran on speed.
Restoring the TD-124 is really something of an art, and there are only a few people I would trust to do it, these would be Hanze Hi-Fi, STS Turntables or Woodsong Audio. I restored about a dozen of them, but these guys are all better at it than I ever was.
Thank you for the detailed reply, it's a nice list of areas to probe further.
The magnet seems strong but not sure how to measure the strength and the acceptable range. Have seen used ones for sale on eBay considering. The pulley seems to be oriented correctly (larger diameter on top from the pic I took).
Would like to think that the Swiss outfit that did the restoration and upgrade would be amongst the top places to do such work on Thorens and so most of the boxes should be checked but will find out... The main visible change is a new bronze bushing replacing the plastic bushing used in the bearing for early model TD-124's and new/upgraded motor suspension and springs. The motor and chassis were are also restored. Had a similar rpm issue before the restoration work.
The magnet seems strong but not sure how to measure the strength and the acceptable range. Have seen used ones for sale on eBay considering. The pulley seems to be oriented correctly (larger diameter on top from the pic I took).
Would like to think that the Swiss outfit that did the restoration and upgrade would be amongst the top places to do such work on Thorens and so most of the boxes should be checked but will find out... The main visible change is a new bronze bushing replacing the plastic bushing used in the bearing for early model TD-124's and new/upgraded motor suspension and springs. The motor and chassis were are also restored. Had a similar rpm issue before the restoration work.
Can't you contact the Swiss outfit who did the restoration?
They must have noticed the same problem you have. Both the speed knob and magnet completely at their extremes is certainly not normal.
Hugo
Recommendation would be to check mains voltage and change tap setting if necessary, and look at the belt. I worked on several 124 with the nylon bushing and replaced them with oilite bushings. The housing diameter varied over time and I had trouble sourcing the correct bushings on a couple of occasions, but did finally end up with ones that work.
Check that belt. Did they replace it? The Hanze Hi-Fi belt will give good results.
Finally perhaps look for a newer magnet or get yours remagged if possible.
A more draconian option might be to get a new main bearing with proper clearances if this proves to be the problem.
I believe I know who you are referencing and if so they ought to have done a good job, possibly the problem manifests when set up for 60Hz operation, presumably they would have tested at 50Hz.
I run mine on a crystal controlled drive that I designed for it more than a decade ago. I also have a papst motor I used in my other TD-124 which was a late production pre MKII unit. I kept the MKII.
Check that belt. Did they replace it? The Hanze Hi-Fi belt will give good results.
Finally perhaps look for a newer magnet or get yours remagged if possible.
A more draconian option might be to get a new main bearing with proper clearances if this proves to be the problem.
I believe I know who you are referencing and if so they ought to have done a good job, possibly the problem manifests when set up for 60Hz operation, presumably they would have tested at 50Hz.
I run mine on a crystal controlled drive that I designed for it more than a decade ago. I also have a papst motor I used in my other TD-124 which was a late production pre MKII unit. I kept the MKII.
Have a look at the third last post here: https://www.audioasylum.com/cgi/vt.mpl?f=vinyl&m=1074822
Hugo
Hugo
Exactly my thinking on testing on 50Hz vs. 60Hz. Since now a couple of votes on playing with voltages I will take that next step.
Waiting for their return to office in ~a week. Agree with your observation on knob/magnet extremes not normal and certainly intriguing...
Thanks, this is intriguing as I am using a new Swissonor non-magnetic platter with the TD-124. Not sure if any implications. Probably need to use the original iron platter to double check...
The belt is a new Swiss made one. No brand info.
That thought crossed my mind as well, wondering other than the motor pulley orientation (which is correct), what other factors might be at play in setting/fine tuning the table for 50Hz vs. 60Hz...
Also, based on various inputs above, it seems the exact AC voltage used has a direct impact on rpm? If so could argue at a given voltage pin setting plus the mid-range of the fine tuning knob, the rpm would be exact at the mid-point of the voltage range (110V in my case) and goes up and down from there? I think this is in high likelihood the problem I am dealing with...