TD125 speed
Hi singing
What I suggest you do is initially mark the positions on to the PCB of all the variable resistor wipers with something indelible, then give them all a squirt of IPA and wind the controls back and forth to clean the tracks and wipers or scrub them with a small stencil brush. Let them dry off, then set all the wipers to their marked positions and you should be very near to the original settings and speeds.
John Caswell
Hi singing
What I suggest you do is initially mark the positions on to the PCB of all the variable resistor wipers with something indelible, then give them all a squirt of IPA and wind the controls back and forth to clean the tracks and wipers or scrub them with a small stencil brush. Let them dry off, then set all the wipers to their marked positions and you should be very near to the original settings and speeds.
John Caswell
Thanks
Hi John,
As promised some feed back on your advice. The IPA spray, plus some action with a tooth brush worked a treat. 1st time it didn't work so well, so I did it again and re-cleaned. Speed goyt much more stable. I then fine tuned the position of the wipers by moving them very slightly (clock wise and anti clockwise) from underneath the deck and checking to see what affect this had on the speed and pitch control. Some crazy results if you over-do it...
Very happy with the results, thanks for you advice.
Ed.
Hi John,
As promised some feed back on your advice. The IPA spray, plus some action with a tooth brush worked a treat. 1st time it didn't work so well, so I did it again and re-cleaned. Speed goyt much more stable. I then fine tuned the position of the wipers by moving them very slightly (clock wise and anti clockwise) from underneath the deck and checking to see what affect this had on the speed and pitch control. Some crazy results if you over-do it...
Very happy with the results, thanks for you advice.
Ed.
Mark Kelly said:
You'll also need to replace the 250uF phase shifting capacitor normally used for 16rpm with something like 33uF + 10uF in parallel to get the right phase shift on the motor winding.
Set the voltage to 8Vrms as per 45rpm operation or more if adjustment range is sufficient.
I can't say whether or not any of this is a good idea, and possible problems with the power amplifier and motor could ensue. Use at own risk!
Using a KAB Speedstrobe, I'm noticing an apparent drift in speed with my TD 125 MKII. It's also hard to get the speed right in the first place, as if the speed control seems to be sticking and letting go (so fine tuning is more of a slingshot operation! 
). ;-)
I've also noticed that after I get the speed apparently right, and record (to digital) an album or two, the speed seems to have changed - test is always without a record or other weight on the platter.
I'm learning about stylus drag, etc., but I didn't think such a thing was an issue with my MkII's 16 pole motor. Ah, learning curves.
I'm following up on this thread to ask:
1. What can I do about an apparently unresponsive speed control - clean, replace?
2. Is a motor problem causing drift? If not, what's the most likely cause?
I've been using a KAB Speedstrobe for a while now, but only recently noticed problems with setting and keeping the speed.
I've changed arms on my table, but I don't do well with soldering, etc., so advice on the practicality of fix attempts vs turn table replacement would be appreciated. What's a good choice if necessary, when considering the cost on 500 recording sessions or so.
Thanks
). ;-)I've also noticed that after I get the speed apparently right, and record (to digital) an album or two, the speed seems to have changed - test is always without a record or other weight on the platter.
I'm learning about stylus drag, etc., but I didn't think such a thing was an issue with my MkII's 16 pole motor. Ah, learning curves.
I'm following up on this thread to ask:
1. What can I do about an apparently unresponsive speed control - clean, replace?
2. Is a motor problem causing drift? If not, what's the most likely cause?
I've been using a KAB Speedstrobe for a while now, but only recently noticed problems with setting and keeping the speed.
I've changed arms on my table, but I don't do well with soldering, etc., so advice on the practicality of fix attempts vs turn table replacement would be appreciated. What's a good choice if necessary, when considering the cost on 500 recording sessions or so.
Thanks
Service manual
Service manual downloadable from here :
http://www.vinylengine.com/library_model.php?make=Thorens&selected_model=TD125
Service manual downloadable from here :
http://www.vinylengine.com/library_model.php?make=Thorens&selected_model=TD125
TD125 speed change
Hi 600
I think the first thing you should do is either clean with IPA or replace the speed adjustment pots on the motor drive board. The main problem appears to be the silver wiper track becomes black with Silver Sulphide so cleaning it with IPA and putting a very light smear of silicone grease on them will help.
If you mark the position of the wipers with an indelible pen, as I have said before, it is pretty easy to get back to square one.
To set the Wein bridge pots you really need a 'scope to look at the waveform.
John Caswell
Hi 600
I think the first thing you should do is either clean with IPA or replace the speed adjustment pots on the motor drive board. The main problem appears to be the silver wiper track becomes black with Silver Sulphide so cleaning it with IPA and putting a very light smear of silicone grease on them will help.
If you mark the position of the wipers with an indelible pen, as I have said before, it is pretty easy to get back to square one.
To set the Wein bridge pots you really need a 'scope to look at the waveform.
John Caswell
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.