Hello everyone! I created this new thread so I don't clog up Valentin's SONY TPS-L2/WM-3 restoration tutorial (mechanical), so I'll jump straight into describing the problem. I recently bought a TPS-L2 that's in very good visual condition (I managed to lower the price to $125 because it wasn't playing music when the seller pressed play). While waiting for the Walkman to arrive, I ordered replacement belts, idlers (idler tires), and a pinch roller from the FixYourAudio. When the TPS-L2 arrived, I immediately opened it up to see why it wasn’t working (I suspected the belts). As you can see, the interior of this Walkman is in pretty good visual shape, and I believe no one had opened this TPS-L2 before me. The first thing I noticed when I opened it was that the motor was seized. But with a few turns using tweezers and a few drops of sewing machine oil, I managed to unseized it, and now the motor spins without any issues, and it doesn’t make any unusual noises. During the same session, I replaced the belts, idlers, and the pinch roller. When I reassembled it, this is how it played music – Cue sound of a dying coyote: After that, I found Valentin's restoration tutorial and followed all the steps he suggested, which slightly improved the sound/playback speed: But after a few tapes, it reverted to the slow speed and dying coyote sounds. I then disassembled the Walkman AGAIN and this time took out ALL the gears and wheels. I washed everything in alcohol, cleaned all the shafts with alcohol too, and following Valentin’s instructions, lubricated everything with sewing machine oil. I only used multipurpose lithium grease in two spots where he indicated. NONE OF THIS HELPED, THE SPEED IS STILL TOO SLOW. What I noticed is that without a cassette inside, all the gears spin constantly/at the same speed, without skipping or slowing down. You can see it here: But as soon as I insert a cassette (I tried multiple tapes – it's not the tapes), everything slows down, and you can visually see how much the speed has decreased and how the main gear “skips”: At that point, I thought maybe some of the caps on the Servo Amp Board were bad, and the motor wasn’t getting enough voltage (from what I see in the schematic, the voltage on that rail should be 1.3V), so I did some measurements with and without a cassette: Voltage without a cassette: Voltage with a cassette: I'm currently out of ideas... Maybe I missed something, maybe I forgot to check something, maybe something didn’t cross my mind. If you have any other ideas, don't hesitate to write.
The fact motor voltage is higher with load (a cassettte in) is normal, it shows the servo is compensating for the higher load, thus regulating the speed. That is what it's supposed to do. What you're showing with mechanism slowing down focuses on just one gear, which is the gear connected to the takeup reel. The takeup reel assembly has a clutch in it and that clutch is designed to slip. On all cassette machines the takeup reel will turn faster wtih no load (because clutch isn't slipping) than with a cassette in. This is normal and the rest of the pulleys seem to run at slightly the same speed (visually at least). I don't see a significant slow down. However, what I do see is that gear tends to struggle, in a way that it doesn't rotate smoothly but has some points where it gets stuck them jumps. There are a couple of aspects that need to be checked: - takeup torque: without a cassette in stop the reel with your fingers. How much force does it take to stop it ? Is the force constant or varying ? - capstan/pinch roller: is the capstan polished, pinch roller in good condition ? - motor: does it rotate freely by hand without any points where it catches ? - mechanism rotation by hand, main belt removed both with casette in and not;
I've stripped it down again this morning. Cleaned/lubricated/greased everything probably for the third time. Put it back together and I got the same problem I was having the whole time. But then.... I turned my attention at the pinch roller (I wasn't looking at it before because I've already replaced it and thought that everything was fine there). I'VE PINCHED THE BLOODY PINCH ROLLER when I replaced the old one (the first day I got/opened it) and the stupid thing was turning but it struggled a lot!!! After I fixed that mess and oiled a pin that's holding a pinch roller the thing was rotating smoothly and all my previous problems magically went away. Valentin, my man... Thank you sooooo much!! I've struggled a lot this pas few days trying to fix this thing, but I've also learned a lot. Every time a took it apart it took less and less time because I was beginning to understand what I was doing. Once again - this wouldn't be possible without you Valentin!!
Glad to hear you finally found the problem ! Did you end up removing the takeup reel as well ? Ask as that's not exactly easy to do and lubricating that can be done without removing it.
I did. After I took all those other gears out (don't know which one's called what just yet) I used this lever/pry tool on the front - it wasn't hard at all. Used this tool to remove takeup reel
Well, that's interesting. Does your takeup reel have a brass retainer or the shaft is pressed just into the plastic reel ? I asked because on all TPS-L2 units I've seen, there's a brass retainer which is very hard (meaning it won't come out without a puller) to take out. See here: https://stereo2go.com/forums/threads/tps-l2-broken-clutch-gear.9534/ What's your TPS-L2 serial number and what PCB does it have ? The one with electrolytic caps or just tantalums ? Please post a picture with components side.
Shaft is just pressed into plastic reel. US Serial No. 110101; It's one of the earlier Gen 2, if I'm not mistaken.
@Valentin FixYourAudio Speed Calibration Cassette came in. This is what WFGUI looks like (log attached below):
