TD-125 mk1 motor

[bouba1234]

Hello,

I am new here. After many years with my lenco I have bought a TD-125 (first version) last week. The bearing is fine but the motor has some noise.

At 16 rpm : no noise
At 33 rpm : very slight noise when the speed is ajusted at +2%
At 45 rpm : noise (hum) ; I can hear it at 1 meter when there is an absolute silence in the room. The level and the frequency of the noise increase when I increase the speedfrom -2% to +2%

I have no problem to ajust the speed with the strobe at the three different speeds. And it doesn't drift.

Is it the sign of a defective motor or a probem with the old components of the drive board (caps ?) ?

The antiskating is also missing the second weight. Does anyone know the weight of these antiskating weights ? Or maybe a source for TD-125 parts ?

Thanks.

[kevinkr]

I would rebuild the motor drive electronics as it is likely that the phase shift caps have gone bad - and that can cause progressively worse motor noise at the higher speeds. A little noise is normal cm away from the table, but it should not be audible from a meter IME.

I have an original TD-125 MKI which I rebuilt about 2 yrs ago, the motor is original - it was getting noisy and had poor torque.. Speed did not drift. Rebuilding the board solved my problems and ended my constant worry about grenading electrolytics.

You should replace all of the electrolytics on the board, exact replacements are available from digikey or mouser. Try not to replace anything in the oscillator as drift could be your reward.

Service manual is available on vinylengine if you do not have it already. You will need to calibrate the drive electronics after you service it.

Unless this table has exceptionally high hours or has been run with the wrong belt the motor should never need to be replaced. A clue as to how worn out the table is overall will be how bad the main bearing is, and you say it is good..

I've had mine for about 7 yrs with an SME 3009 Series II arm and a Grado Reference Platinum - it's by far the best table I have ever owned and 40yrs young!

Make a very solid wood plinth (use a dense high mass wood) and you'll be surprised at the improvement in sound over the stock plinth.

[bouba1234]

Thanks,
Ok, I must change the shift phase electrolytic caps.
I can see them on the drive board. There are original and must be completly dry !
For the calibration i have downloaded the service manual (chapter 2.2, i think)
Thanks !

[kevinkr]

Originally posted by bouba1234
Thanks,
Ok, I must change the shift phase electrolytic caps.
I can see them on the drive board. There are original and must be completly dry !
For the calibration i have downloaded the service manual (chapter 2.2, i think)
Thanks !

Change the power supply capacitors as well, should one of these fail it could take out the entire drive electronics.

[duderduderini]

Hey
i rebuilt my mark II a few years back and wrote all the values down and posted it to this website
http://www.theanalogdept.com/td125_mkii_circuitry.htm
This site also has workshop type manuals for the mark II at least.. something there might help.
Good Luck
Great turntable
Nick

[kevinkr]

Originally posted by duderduderini
Hey
i rebuilt my mark II a few years back and wrote all the values down and posted it to this website
http://www.theanalogdept.com/td125_mkii_circuitry.htm
This site also has workshop type manuals for the mark II at least.. something there might help.
Good Luck
Great turntable
Nick

MKI drive electronics and motor are different than the MKII, Vinylengine manual has the proper manual and schematics for the MKI.

[bouba1234]

Hello,

I have changed the shift phase capacitors and the power supply capacitors. I have check all the resistors and make a complete calibration with the service manual.
It is better but I still have a "bzzzzzz" noise only at 45 rpm. It's maybe normal but I think it's a bit high.

When I check the different voltages on the board there are a bit high :
21.5V / -21.5V where I must have 16.5V / -16.5V. A 20% variation is tolered as stated in the service manual but here it's 30%.

I have :
- 230V on the input of the turntable
- 220V after the filter capacitor and the resistor for current limitation (check it : value is good)
- And the voltage after the transformer is a bit high.

Any idea ?

[kevinkr]

Originally posted by bouba1234
Hello,

I have changed the shift phase capacitors and the power supply capacitors. I have check all the resistors and make a complete calibration with the service manual.
It is better but I still have a "bzzzzzz" noise only at 45 rpm. It's maybe normal but I think it's a bit high.

When I check the different voltages on the board there are a bit high :
21.5V / -21.5V where I must have 16.5V / -16.5V. A 20% variation is tolered as stated in the service manual but here it's 30%.

I have :
- 230V on the input of the turntable
- 220V after the filter capacitor and the resistor for current limitation (check it : value is good)
- And the voltage after the transformer is a bit high.

Any idea ?

What schematic are you referring to? My MKI has approximately the same voltages present on its supplies (+/-21V) and my notes indicate that this is in the acceptable range. Did you measure with motor running or not? It does drop significantly under load.

You may be able to reduce the buzz on the 45rpm range by playing with the value of the phase shift capacitor. Some noise is normal - mine is not silent at 45rpms either.

[bouba1234]

Hello Kevin,

Thanks for your help !

Yes, it's the mk1 version. There are two versions of the board for the TD 125 mk1. Mine have the second one.

The service manual (on vinyl engine) say : "check the voltages on the board" It's written +16.5V and -16.5V on the board. And I have 22V.
I can't see the 21V you refer as acceptable on the service manual (maybe you have different notes ?)
The motor was running during the measurements. Maybe the value indicated on the board are given without any load (strange no ?).

You may be able to reduce the buzz on the 45rpm range by playing with the value of the phase shift capacitor. Some noise is normal - mine is not silent at 45rpms either.

Ok, so it's normal. Electrolytic capacitors have huge variations so maybe i can find a better value !

[kevinkr]

Originally posted by bouba1234
Hello Kevin,

Thanks for your help !

Yes, it's the mk1 version. There are two versions of the board for the TD 125 mk1. Mine have the second one.

The service manual (on vinyl engine) say : "check the voltages on the board" It's written +16.5V and -16.5V on the board. And I have 22V.
I can't see the 21V you refer as acceptable on the service manual (maybe you have different notes ?)
The motor was running during the measurements. Maybe the value indicated on the board are given without any load (strange no ?).



Ok, so it's normal. Electrolytic capacitors have huge variations so maybe i can find a better value !

I can't provide any good answer as to why Thorens indicated +/-16V vs the +/-21V we both measure. I've worked on at least 4 other decks over the years and all were around +/-21V with an approximate line voltage of 120V.

Did not seem to matter which version of the supply was used. Line voltages are significantly higher here than in the past, and of course Europe has harmonized at 230V resulting in higher line voltages in some places and lower in others.

The voltages that actually matter most are the ones you measure across the motor windings per the calibration instructions.