Hello all, I bought myself WM-DD3, thankfully in very good visual condition. No signs of any kind of mechanical damage on it, looks almost unused. Of course, it came with original black centre gear (broken). Even broken, with clicking mechanical sound, I was able to play the tapes with it shortly, just to test it out and it performed ok for 10mins of playback. But since i didnt want to force it and potentially make a damage on it, I ordered full set from Marian (fixyouraudio). So, centre gear, all capacitors, pinch roller and the rubber ring. I have followed instructions on Marians blog and did everything as described (except for now I didnt change all of the caps, I just changed few of them, found that it was not so easy desoldering the caps that are glued to the board so I had to pause for a while). But even without those few caps I have to change, I wanted to assemble it and just test it a bit longer. So I played Maxel XLII 60mins chrome tape without dolby few times back and forth, start til the end. The sound was good, no issues at all, and the mechanics, almost dead silent, you could barely hear it. Very nice. Then I played some Maxel UD 90mins tape and noticed a problem. When playing the last 10 minutes of the 90mins tape, speed started behaving super weirdly, slowing down and speeding up with pretty obvious sound issues. I was running it on the 3v power adapter, and on the batteries and it behaved the same. I tried ffw and rw just to see if the tape could be the issue but it was rewinding the tape back and forth like a charm, not a single issue nor strange sound. Silent and fast. Also, when playing a normal tape, somewhere in the middle, sound just becomes muffled (like the head is not aligned properly. No matter what you try (stop/start, change the side. similar to when you turn on Dolby NR but worse) it sounds the same until certain moment and it just flips back to perfectly clear sound. I have not noticed any mechanical issues, misalignment or whatever that could cause this issue. Could the issue be related to the rest of the caps I have not changed or there is anything else (mechanically) I should check. Thanks
Update, I found the issue with muffed sound, and slowing down the speed after reading https://stereo2go.com/forums/threads/wm-dd-azimuth-instability.7590/ by @Valentin. So I removed the door and tried to play this heavy Maxell UR90mins tape and what I found out that the moment i help a bit with the finger pushing the pinch roller, the speed recovers instantly. So it could be related to the issue he described even on the old pinch roller looks equally worn. and when I try to push the roller while not playing just to see how it travels up and down I dont seethat the inner part of the roller is far from the rotating capstan. Now I am just now thinking what to do, to bend the bracket to somehow increase the tension with existing spring or replace the spring. But if I want to replace, which one to buy... :S
Muffled sound is not related to the caps. Failing caps would affect the other end of the spectrum (sub-bass), but even then they would have to be off by a lot to cause audible problem. Caps on these DDs aren't a serious problem, despite some of them do age and decrease in capacitance. But most are still within the +/-20% tolerance. The ones I recommend replacing are C102/C202 (10uF - 47uF) and C114/C214 (220uF - 560uF), the rest you can leave alone as replacing them won't bring any audible improvement. In regard to your problems, you mention 2 issues: fluctuating speed and tape path alignment issues. Regarding the fluctuating speed, do you have a W&F measurement screenshot ? As far as tape path goes, there is more than one thing that could cause tape path problems: - up/down drift at the roller. You can observe this with door removed. This can be caused by roller angle, capstan angle or uneven wear on the capstan (which may not be visible); - incorrect head height (unlikely if original shim has not been changed); - incorrect adjustment of the plastic tape guide; In regard to tape guide adjustment it's to be noted the tape guide needs to be set at the same height as the head. The absolute height isn't as critical as it is for the 2 to be the same.
Hey Valentin, highly appreciate your time and advices. So, let me try to provide few more things and clarify what is going on. First of all, muffed sound issue is gone. at least I have not noticed any more since yesterday and I have listened several tapes for several hours today. Caps replaced C110, C210, C114, C214, C701, C302, C315 and C316. I dont see C102/C202 on my images I took when disassembling the walkman. (check attached picture). I have not taken the screenshot with me, but I remember that the frequency I measured when assembling walkman was from 2985 as lowest peak and 3005 as highest peak. However, the tape I have with 3000khz recording was recorded at the beginning. The issue I was having with slowing down is happening in the last 10-15minutes of 90mins tape only, and I tried applying slight pressure with my finger to the pinch roller bracket, the speed stabilizes instantly and I have not noticed any w&f. I have tried to bend the roller bracket part where the spring is attached and the issue was significantly reduced, now I can barely notice the slow down in the last 5 minutes of 90mins tape. Issue does not exist on 60minutes tapes at all. Also, I have rechecked the plastic tape guide alignment with the head and I could not see discrepancy in height. After playing all those longer tapes, whenever the slowdown happens, I try to stop and recheck the actual tape to see whether it was diverting from the expected path, I would assume in that case, the tape would be damaged at the edges. Also, except the pinch roller, nothing has been touched / changed. The factory glue on silver spring between the head and the door frame is still there. Considering the condition of the walkman outside and inside, I would highly doubt that anyone serviced it ever and that was very lightly used. Rechecked alignment between the pinch roller and capstan and everything really looks like aligned and normal.
C102/202 are SMD tantalums on this models, these are on the other side of the PCB near head preamp IC. See picture attached. If you bought the kit from FixYourAudio, 47uF SMD replacements are included in the kit. 20Hz variation is a bit much, also the walkman shouldn't struggle with 90min tapes, even longer ones should work. Fact increassing the roller pressure attenuates the problem indicates the capstan probably doesn't have enough grip. You can etch it with ferric chloride, it's a step worth doing just to eliminate this as a potential problem. Would also double check the rubber disc, by cleaning it again with IPA. Any kind of contamination (even from fingers touching it by accident) can crease slipping of motor spindle, which will result in decreased speed/increased W&F especially at high load (end of tape, longer tapes). Also check the flywheel thrust play, if rubber disc used is thin, too much play can result in motor not having enough grip, especially when walkman sits with buttons facing up. EDIT: As for W&F a measurement is ideal. Fact you can't hear it depends greatly on music type. It can be 0.3% and not hear it or it can be 0.08%.
Ok, yes, you are right, I got those caps from Marian, I will try to change them too and to clean again the rubber disc, it was changed together withe centre gear and also ordered from Marian (this is the only place I order stuff for walkmans anyways). Also, I will try to find ferric chloride somewhere in the store and etch the capstan. Then I will measure the w&f again. Thanks for all the help Valentin EDIT: So, I will try to swap the capacitors during the weekend. However, I had 10mins free this morning to check the rubber ring and the disc, and indeed, there were some fingerprint marks and also just a tiny bit of grease on the edge (probably I touched it by accident when assembling the centre gear). So I have cleaned with IPA both disc and the rubber ring. Tested the 90mins tape end and its still slower than it should be, I didnt notice fluctuations of the speed just by listening but only slowing down. So, first I have no clue where to find Ferric Chloride in Norway as I found no.mouser.com is actually not shipping it. When I find it, I will use the guide from here https://stereo2go.com/forums/thread...newely-bought-sony-d6c.8383/page-3#post-79354. Very helpful Btw, about Ferric Chloride, do you have example of the product you buy?
Found this one, it says: concentrated 0.25 liters For etching metals. Etching should be done at room temperature. Test a smaller piece of steel first to determine how strong the etching is. For strong etching: Mix with water 1:1-1:4 For moderate etching: Mix with water 1:5-1:8 Neutralization: In a solution of bicarbonate and water. So, should I use distilled water (that usually goes to the car batteries) or just go with regular water?
For this application, you use the substance as-is, no need to dillute with water. Soak a cottom swab in it, put unit in FF or REW and keep the swab against the capstan on area where roller touches until the surface becomes dull. Use another clean swab immersed in IPA to clean the capstan. Also clean the roller to make sure you won't contaminate your tapes.
The substance has arrived. Straight from work went to finish this. Attached images of pinch roller after the treatment with Ferric Chloride and also replaced C102/202 capacitors. Tested with couple of 90min tapes I have so far (only playing for the 10 minutes) and I could not hear any sound/speed deviation. Also, measured while the walkman was still in pieces wow/flutter (attaching files here). I was checking the service manual and not sure if I understood correctly, but there they mention 3000Hz (+9Hz) is ok. I have not seen after few minutes measuring the w/f this goes bellow 3007 and above 3009Hz on 3kHz test tape. I am not sure if this is perfect (from the technical point of view) but sound wise, this sounds great. Only difference compared to my Yamaha deck is that it has stronger bass, and that the output is a bit higher than the deck when playing on Volume 6/7 on the walkman. For the cassettes I recorded, this is max before I start hearing some short distortion when highs are having a peak.
Not sure if its better to make a separate subject but I would assume its better not to open another thread for the same model (different unit than in original post). So, all the same as above Wm-DD3 Replaced the full set of parts as the first unit + Recapped all the caps Changed small gear on the takeup reel. Did a brief test and no crackings nor noisy mechanism, everything seems fine. Except When I press play, the speed is lower than it should be. When I touch the capstan flywheel (it does nor matter where, just to apply a bit of pressure to make motor work harder, speed instantly recovers and it holds the speed. Soundwise, its good. Once the speed recovers, everything is fine. But every time i stop and play again, same thing happens, slow speed, then touch any part of mechanism to force motor work harder, speed recovers. I tried resoldering zener diode (at least I think thats zener diode marked with ZEE), next to C701 capacitor, as I found that here on the forum. Anyone experienced any similar behavior or has any idea what else should I try? Thanks
D701 is a 7.5V zener diode, used as a voltage reference in the DC-DC converter circuit. However thid DC-DC only powers the PLL, so it's easy to isolate a potential fault by simply removing the PLL solder bridge. Also, what happens to the motor voltage when speed is low ? Is it higher than 1.45V or lower ? When you load down the motor by touching the flywheel, voltage goes higher or lower ? If servo is working correctly, it should sense the speed going low and raise the voltage to compensate for the higher load.
I just measured the voltage, when I start (low speed) the voltage is 1,54V, When I touch the flywheel and speed recovers, voltage is 1,65V steady which corresponds to exactly what you said. When you say solder bridge, yo think of long solder between white motor wire and C316 leg?
Don't think you understood how to do the test. We're interested in the voltage WHEN (at that exact point, not after) the motor is slowed down by hand, not after it recovers. Point is, if the servo is working correctly, it should instantly increase the voltage when the FG coil senses a slowdown in speed. If I understood your measurement right, it does seem like a servo problem as the voltage is 1.54V initially and jumps to 1.65V after the recovery. Regarding the PLL bridge, check the service manual page 5 (pages 7-8 in the actual manual), Tape Speed Adjustment section. You'll see at the bottom the solder bridge labeled "Adjustment patterns".
The voltage jumps to around 2V instantly when I touch the flywheel and then when I release the finger from it, it goes back to 1.65 with recovered speed. Also happens if I try a couple of times to do the same, then the speed sometimes goes back to low, and the voltage is again 1.54V Desoldering the bridge “Adjustment patterns” turned the speed way lower. Of course, touching the flywheel would not recover the speed in this case. Update 2: Resoldering the bridge and adjusting just a little bit RV601 fixed the speed permanently. Now whatever I do, (stop/rewind/ff/play/touch the flywheel) speed is ssteady and this is what I was getting when measuring w&f.
Looks much better than before, but that W&F is high. Recommend doing 2 things: - oil the front bearing of the motor if you haven't done so already; use the walkman a while after this to make sure the oil got inside the bushing. - adjust RV601 correctly. Speed with bridge desoldered should be adjusted to 3090Hz, then bridge should be re-soldered. From the 3090Hz I would also substract 7Hz since your tape is likely a bit off. So you can adjust to 3083Hz instead. This RV601 adjusment, when it's at the extreme ends, causes erratic behavior of the servo. Given in your case the speed way way lower with bridge desoldered, it's clear this adjustment was probably close to the min.
Thanks a lot Valentin. I will try again. Maybe I overlooked something on the motherboard but I was a bit confused when I desoldered the bridge, the speed dropped lower than before and with the bridge desoldered, moving R601 didnt do any speed change. I was turning it counter clockwise. After soldering the bridge, and turning R601 all the way to the end counter clockwise, speed recovered and now always at 3007Hz constantly, I could play, stop, ff, fw... it always works correctly. I will give it a try one more time following your recommendations.
If RV601 doesn't change the speed with solder bridge open, that indicates a fault inside the CX20084. Assuming that's the case, there's nothing more you can do apart from what you have done already. You could eventually try to adjsut for a minimum W&F using WFGUI.
