The power supply on these Is a Wein Bridge Oscillator (notice the small lamp on the board) and *it's the non-polar coupling caps that are particularly prone to failure*, preventing the motor from spinning. The motor is a synchronous type that runs on AC voltage, not DC, and therefore is not only immune to speed drift as it warms up or cools down (as long as the AC frequency from the power supply remains consistent) but also has a longer lifespan than most DC motors ---- just like old-fashioned analog clocks that can run for many decades. 99.9% of the belt-drive turntables you will see with pitch controls are utilizing DC motors that get wonky with age and the speed drifts as they warm up (and sometimes the pitch control potentiometers wear and cause speed stability problems as well). I briefly owned a Thorens TD115 with DC motor and standard power supply that tended to drift and the speed adjustment pot was finicky; I modified it with a pair of resistors and a lower value speed pot, reducing the range of adjustment but making it easier to fine tune. Most Thorens turntables have crappy tone arms anyway, and the other models with pitch adjust are best avoided, but the TD125 is a winner. I've owned one and repaired several for other people, and with a good tonearm on them, they perform very well. By the way, Thorens used to make a DJ kit for these, a set of rubber cylinders that replaced the springs, to make the suspension stiffer for people who were spinning records professionally with them! I've never seen ATD125 that was equipped with those, and it's also worth noting that I've never had to replace the suspension springs on any of them.
Cool. Good job broseph. I built a 1/2" thick mdf base with speaker damping sheets on it and stored the crappy base. I just did a Luxman PD277 last night. Definitely a keeper. Had another crack at the JVC QL-F4, but no progress. Going to part it out.
I never cared for the SME tone arms but there was a Mission 774 arm that used the same base mounting geometry and which was extremely rigid, highly adjustable, had low friction bearings, and (optional) silicone-fluid resinance damping. An excellent arm, even with low compliance moving coil cartridges, and a great match for the TD125.
If you check for continuity with a multimeter you will discover that the main bearing-well, and therefore the subplatter and outer platter, are not actually making a ground connection due to the heavy gray anodizing/paint of the plinth, and the bearing-well having been crimped into place. In a low humidity environment, any static electricity that builds up on the record as it plays cannot be drained away and dissipated to ground through the platter, and might instead create static pops through the cartridge and into your audio system. You can fix this by adding a ground wire from the outside of the bearing well to the metal plinth or other internal grounding in the turntable (if you clean the metal and use a high wattage soldering iron or gun, you can solder a wire to the side of the bearing-well; or attach the ground wire with a metal hose clamp instead). Note that it is best NOTto use an audio- signal shield-ground as your bonding ground to get rid of hum and buzz and RF and static electricity, but unfortunately many turntables and tonearms do exactly that, including some SME arms if I remember correctly.
Hi, SME 3009 series II (I think) tonearm has a separate grund connection at the bottom connector, problem is some people don´t know what a ground loop is so they atttach the ground pin to RCA females at the back instead of running the tonearm ground cable to the phono preamp. I have this same Thorens TD 125 MKII and there is continuity between the bearing well to the metal plinth , maybe previous owner modified It (I don´t see any ground cable run from the B. well to the plinth or ground connection. Anywat It´s a good advice to check continuity just to be shure, and while you are there check if tonearm ground is separate from audio shield cables. Cheers.
In it's days, these Thorens turntables had been one of the best serious belt driven sub chassis record players. Due to the fact, Thorens tonearms never had been top, you could order with SME, DynaVector or Koshin Lustre. I got the MK III Electronic from our father after he went on with the worlds best tonearm GST-801 (the first, one and only E-M mechanical Q-Damping) I think the spring problem (I realised also) Is because of the heavier non Thorens tonearms. I will investigate if it is because the springs got tiered. I prefer direct drive, and in these days I had chosen the DENON DP-57L with electronic Servo Tracer Q-Damping still running fine. On my YT Channel there is a MK III video few months ago with a Heino tune "Kein schöner Land"
There are aftermarket springs with different rates of tension available. This owner wasn't interested in replacing the existing springs. They're probably a little worn out at this point.
Hey Turntable Guy. Thanks for the video on the Thorens. I have the earlier late 60's Mk1 version of the TD125 with the awesome Rabco linear tracking tonearm. I originally worked on this unit for a friend. After repairing it I ended up purchasing the turntable because my friend was no longer listening to records that often. I love the Rabco tonearm. Very cool and simple implementation of a linear tracking system. Have you ever worked on one of these? Here is a link to my repair video. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-XF-1iOY51K4.html It looks like we had many of the same issues with the turntables.
obviously you didn't handle a Lenco platter and, actually, your repair is not done well: the red lever for speed control supposed to be in the center if the strobe markings are on a stand still meaning that the speed is what it supposed to be
Maybe for you, it isn’t, but for others it is and saying that the position of the pitch is not important, coming from someone who calls himself a turntable guy is wrong as wrong can be. Plus, you didn’t clean the pots either, you used a cheap generic belt which, in the long run, can cause troubles and, all in all, you only did a shallow repair. I’m saying all of this because this machine is an icon in the history of turntables and deserves a proper going through
