Hi all, the other day I finished doing a nearly complete service to a Sony WM-5 (Basically a WM-2 in a metal case) But the wow and flutter is still pretty mediocre. So today I started going off of potential culprits including the motor so I put a very tiny drop of watch oil into the top of the motor bearing and when I went to test it the tape started to unspool backwards. On closer inspection the whole mechanism is running backwards. it ran forwards last night and all I've done since then was pry the motor pulley out a little and put a very small amount of oil in it. Any advice? Thanks in advance.
There is something else causing your mechansim to run backwards. The fact that you put oil on the motor has nothing to do with it. Make sure the belt is routed correctly, as it's very easy to put it backwards on the motor pulley. As for increased wow&flutter, there are a couple of aspects that need to be done before assuming anything: - diassemble the mechanism, clean all the shafts of rotating parts and relubricate them with oil; - if center gear is broken, replace it; not sure if this one uses 2 types of center gear or just the one that breaks; - lubricate the capstan bearing; - clean the pulleys' grooves very well, even sand them with 800-2000 grit sandpaper if the residue is still there; if you sand, do it by keeping the paper in fixed position and rotate the pulley to avoid creating low spots; - change pinch roller if it has cracks, glaze or indentation marks; - bent pinch roller bracket is common in these (as in DDs): should be solved in principle, despite it's unlikely to affect the W&F. - if capacitors show signs of leakeage, you should replace all of them; please provide a picture for reference; - speed trimpot should be thoroughly cleaned with contact cleaner and turned back and forth 10-20 times to make sure the cursor makes a good connection with the carbon trace; What is the W&F figure you were getting ?
Thank you for the advice about the belt being routed backwards! Looking at the mechanism I thought there was only one way to route the belt but this morning I took the belt off and put it back on again and now it's running normal. And to answer your question I don't have a number for the wow and flutter I've just been going off ear for now using a 3khz test tape and some music that is very sensitive to W&F. The W&F is somewhere in the middle in terms of the rate of the speed fluctuation so everything has a irregular vibrato effect. The pinch roller does have some rings going around it although adding pressure to it didn't affect anything so it's not slipping, but I should just replace it anyways, The center gear was making a scraping sound but if pushed down very slightly it went away so I added a 2nd washer to lower it slightly, I didn't notice the W&F get any worse after doing so but could also be a culprit, And the center gear still makes a quiet grinding sound so I think it needs more angle adjustments (even after adjusting it for like 45 minutes the other day). Oh and also the brass pulleys have Stains (don't know what else to call them) where the old belt used to be (The old one completely melted into tar) could that be causing the W&F? Also, can bad capacitors affect W&F significantly or at all? There's no signs of leakage and the audio output works perfectly fine but they are 40 year old caps afterall... Thanks again!
You did not mention: what type of center gear do you have ? The full plastic one or plastic molded onto metal disc ? Pinch roller, yes, I would replace it anyway. Look here for the bent roller bracket issue: https://stereo2go.com/forums/threads/wm-dd-azimuth-instability.7590/ Roller does not need to slip to increase the W&F, some irrregularities on its surface are enough to cause woobliness. Stains in the pulley's grooves, yes that can increase W&F, absolutely needs to be cleaned as mentioned before. If alchohol does not clean them, use sandpaper. As for capacitors, if they're not leaky ignore them. I do remember a WM-5 with leaky caps, but it is very likely there is more than one brand of capacitors used in these walkmans, so yours probably uses some that are not prone to leakage. Of course, replacing them is not a bad idea, but you can think of this after the device works as it should, as an upgrade if you really want it. As for the figure itself, don't expect miracles in regard to this WM-5. 0.2% WRMS or a little bit less is as best as you will ever get. As for testing, you really need to measure the value with WFGUI, otherwise it's hard to tell what is too high.
Thank you for your advice about the pinch roller, I'll align it when I replace it later. The center gear I'm using is the 2 piece design that screws together. I've had it for a few years from when I tried to repair a WM-2, but it ended up being to heavily water damaged so I boxed the parts and kept the center gear. It was a little bent when I pulled out for this current project but I straightened it out (or at least tried) and tightened the two parts the correct way (same way you tighten the lug nuts on a car tire). I thought about buying a moulded center gear but I feel like that one would eventually crack aswell or isn't as good quality as the 2 piece gear. In the uploaded screenshots you can see the W&F level I'm currently getting.
Have to say the starting figure is not actually that bad. It most likely can be improved, but you will need to do all the things I mentioned, maybe even eliminate the eccentricity of the center gear to reduce this figure significantly. So, in regard to the center gear, it is only the type with metal disc and you replaced it with Marian Mihokm's version (fixyouraudio.com). It is to be noted the center disc has some eccentricity in most cases, which will also cause periodic gear noise. This is solved by filing the inside of the gear and installing it opposite to the eccentricity of the disc. It will take some time until you make it good, but it is worth the effort. You should take the small idler gear as a reference and rotate by hand. When the gear is in correct position, the edge of it will not go up and down anymore relative to that small gear. Another aspect to be done is this: https://stereo2go.com/forums/thread...-wobble-problem-and-solution.7387/#post-53936 Check the link in my signature for all the tutorials I have made. For the lateral eccentricity I don't have one yet unfortunately, but can explain how to do it. Given the waveform shown in WFGUI (looks like a slow almost sinusoidal variation), I'm inclined to believe it's the center gear eccentricity that causes this increased wow&flutter.
