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Topic: Thorens TD 125 MK II speed problems (Read 12388 times) previous topic - next topic
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Thorens TD 125 MK II speed problems

I've got two Thorens TD 125 MK II's.

The first, I have have had for years, with the original Thorens arm. I bought a second one on eBay with a SME arm. Then I moved to Thailand where electricity is 220/50. The SME table had been modified so that I couldn't change the fuse for 220, but it worked for a while with a step-down transformer before failing.

I started using the old table with the SME arm, but noticed that I could see speed variations. This despite a UPS and/or AVR.

I got various kinds of advice from all over, including cleaning everything, oiling the spindle, new belt and pulley, capacitor change and speed controller tweaking.

I got the help of a local technical wiz to do all of the above, but the old table would still not keep a steady speed over time. So, he got the eBay table working again, but is also varies in speed.

He's ready to try the capacitor change on this one, but other than that we don't know what to do.

I suspected that I might have electrical problems, but the UPS or AVR should correct for that according to my tech. Someone here suggested that is not true as far as the UPS goes (in another thread), but the AVR should be taking care of this.

I don't expect the table to start up to the correct speed, but I need it to stay where I set it long enough to correctly record a few records, which I'm archiving to FLAC (record once, listen many times).

What can I do to stabilize the speed at this point?

Thanks,
Gritingrooves

Thorens TD 125 MK II speed problems

Reply #1 –
By "speed controller tweaking" do you mean pulling the bottom cover off the table and turning the internal potentiometer with a screwdriver?  That is what I used to do with my TD125.  Would hold a steady speed for a week or so after that.  Eventually the pot reached the end of its travel and I got a different table.

Thorens TD 125 MK II speed problems

Reply #2 –
Thanks for your reply, Apesbrain,

By 'tweaking', I meant adjustments made by my repair man.

Here's a follow-up. I've had two people work on my table now. It's with the 2nd repair man, who is telling me that the table is fine, but I'm still having one, maybe two, problems.

Since the earlier repair, the pitch control seems too sensitive to changes. If the table is running just a little slow, based on the built-in strobe, and my speedstrobe tester, a small change to the pitch wheel will cause the table to start going a bit too fast, and vice versa. Seems impossible to get it right.

I'm asking the repair man to adjust the pitch wheel assembly to require more movement for a small change in speed. Still trying to get him to understand that.

Is actually something that can be done? There used to be more "play", that is, movement of the well required, for a given change in pitch.

The other issue is that he is saying that the reason I have trouble with the speed is that I'm using the KAB SpeedStrobe instead of the built in strobe. I'm trying to tell him that I see the problem with both strobes.

I guess one concern is that the KAB is more accurate than the Thorens strobe. It tests to a 1% accuracy, but I think the table allows for 3% variation. True? At any rate, how do I convince the repair man that what I see with the KAB SpeedStrobe is correct speed information?

-Gritingrooves

Thorens TD 125 MK II speed problems

Reply #3 –
If the speed adjustment is a potentiometer then it has probably gotten noisy and needs to be sprayed with some contact cleaner.

Also, just turning it all the way up and down several times can improve it.

Thorens TD 125 MK II speed problems

Reply #4 –
Quote from: pdq on
If the speed adjustment is a potentiometer then it has probably gotten noisy and needs to be sprayed with some contact cleaner.

Also, just turning it all the way up and down several times can improve it.

Thanks for your suggestion, pdq. The pitch control has recently been cleaned and calibrated, but I think the technician(s) didn't do it right.

It's not that moving the wheel doesn't change the speed, it does so consistently but too much for a given change, based on my testing.

Thorens TD 125 MK II speed problems

Reply #5 –
Quote from: pdq on
If the speed adjustment is a potentiometer then it has probably gotten noisy and needs to be sprayed with some contact cleaner.

Also, just turning it all the way up and down several times can improve it.


Contact cleaner is rarely satisfactory long term. Replacement is a much better bet.

G²

Thorens TD 125 MK II speed problems

Reply #6 –
Today I found a direct number to Thorens (for dealer references). They confirmed that there is no dealer in the country where I live (Thailand) and Thorens has no spare parts for the TD 125 MKII.

Based on feedback on other forums, I'm starting to think that the main reason my tables aren't keep a steady speed is wear and tear. Maybe it has needed proper lubrication for a long time, and I neglected it. But finding the parts to fix it (new pulley, etc.) maybe be next to impossible.

So, since I really only have a few hundred records I'd like to record, I have to think carefully about what turntable to buy as a replacement (is it worth it).

The two things I'd hope to find in a new table are:

1. Pitch control
2. Compatibility with my Grado cartridge (which I use with a Grado phono stage)

Any reasonable suggestions?

Thanks,
Griggo

Thorens TD 125 MK II speed problems

Reply #7 –
Did you replace the e-cap on the PCB? Since 125 is old and the e-cap need replace for sure.

Thorens TD 125 MK II speed problems

Reply #8 –
Thanks for your reply (and all replies).

I'll certainly double check, but I do recall my friend replacing a capacitor. 

Thorens TD 125 MK II speed problems

Reply #9 –
I own a TD 125 MKII myself.  You can download the service manual for the TD125 MKII by going to www.vinalengine.com.  It gives you instructions on how to correctly adjust the 3 speeds.  You will need a volt meter and a small screw driver. You set the red adjustment wheel to the center, Connect the AC meter to the soldering points "ge" and "rt" of the printed circuit board. Adjust voltage at 45 RPM to 6volts by using potentiometer A1 45; 33 1/3 RPM to 5volts using Pot A1 33;  16 2/3 RPM to 3.2volts by using Pot A1 16.  That is phase one, for Phase two Connect the AC meter to "ge" and "bl" of the printed circuit board.  Adjust voltage at 45 RPM to 6volts using Pot A2 45; 33 1/3 RPM to 5 volts using Pot A2 33 and 16 2/3 RPM to 3.2 volts using A2 16.  Final phase: Adjust the speed Pots F45, 33 and 16 to a standstill of the respective strobe ring.  When this adjustment is done recheck the voltages of the first two phases.  I hope this helps.

JFCHI

Thorens TD 125 MK II speed problems

Reply #10 –
I have again attempted to re calibrate the speeds on the TT by following the TD 125 mk ii service manual on Vinyl engine, as follows;
Connect meter (dmm) to test points ge and rt (phase 1) and adjust:
45rpm set R10 for 6V
33rpm set R9 for 5V
16rpm set R8 for 3.2V


connect meter to test points ge and bl (phase 2) and adjust:
45rpm set R13 for 6V
33rpm set R12 for 5V
16rpm set R11 for 3.2V


Speed adjust:

set pitch control to centre position and adjust:
45rpm set R18 for stationary display on strobe ring
33rpm set R20 for stationary display on strobe ring

16rpm set R22 for stationary display on strobe ring

Repeat until no further change noted.
16 rpm and 45 rpm are setting perfectly, but despite repeatedly measuring the voltages and re setting the PCB pots over several months, I am still unable to set the 33 speed so that the strobe is stationary. I am wondering if one of the component, which are specific to the 33 speed (R21 and C12) might be at fault. I am assuming that the TT has been mostly used on 33 over the years and therefore components are likely to at fault when in this speed setting ?

Any help would be really appreciated.

Happy New Year everyone.

Graham