hi everybody! I have a D6C and thought its easy to fix everything((( but when I fixed it I have confused polarity of battery and applied this block to circuit. then I have read that it can cause servocontrol immediate damage. May I ask you please how to check it? How to understand if I broken my servocontrol? It seems for me I hear a little bit w&f after reading an article But maybe its just my imagination? What is the signals that should show me that servo is dead or broken? thank you veeeeeeery much! in short: does confusing polarity cause immediately damage of servo and what are signs of it.
The typical symptoms are motor running at much higher speed than normal, very high wow&flutter and the motor running even when the unit is stopped. It depends on how lucky you are, but usually it does cause immediate damage because the servo IC power lines are connected directly to the battery terminals/DC IN jack, so you don't even have to press play to cause damage. What do you mean you hear a little bit of wow&flutter ? Was it there before ? Is the unit serviced ? (new capstan ring rubber, mechanism lubricated, etc). On a serviced unit, the wow&flutter is extremely low, at about 0.04% WRMS, which you certainly wouldn't be able to hear, unless you have a bad tape with lots of friction. If the unit runs at the correct speed, I would check other things first, like cleaning the head, pinch roller and capstan. Wow&flutter can have different causes than a bad servo IC.
Dear Valentin. Thank you for reply. I have no speed problem, except only Speed Tune doesnt work (frankly to say I even didn't check it before this case). Steed Tune ON - and it stops playing. Speed Tune Off - and its plays. Yesterday I played different tapes and didnt hear such big amount of Wow&Flutter. Maybe it was caused by cassette itself and I was a shocked a little bit and after reading the article I thought that servo is dead. I have serviced it myself - changed all rubber parts in mechanism. After changing rubber things I decided to apply battery block to check how it works while I didnt close cover(((( Maybe Servo didnt damaged - I do hope for it. The main reason that I decided to change every rubber part was the problem - when I change position of payer - it OR stops paying OR slow down. I suppose that doing rubber parts replacement I solve this problem. I really dont understand if it damaged because all that I have read - it will cause immediate damage. Will try to check mechanics and lubricate it. May I ask you if there are any guide how to check it and which need to be lubricated? Thank you. Kind regards. Vad
Ok, I have a clearer picture of what the situation is now. The fact that you run the unit without the bottom cover can't cause the servo to go bad. You say the the unit had a problem before, where if you tilt it it slows down or stops. Did replacing the rubber solved that problem ? It is important that you set the motor perfectly perpendicular to the flywheel when reassembling, as there is play in its the screws (most people ignore this, but this causes the unit to be noisy and to have high wow&flutter). I don't have any guide specific to the WM-D6C (although I do intend to make one in the future), I can give you a link to the TPS-L2/WM-3 which has a 90% identical mechanism, except for the disc drive part. The points that need lubrication are the same on the WM-D6C. https://stereo2go.com/forums/threads/sony-tps-l2-wm-3-restoration-tutorial-mechanical.7123/ However, note that this mech-relubrication is not a beginner job and it's very easy to loose split washers or other parts so do it at your own risk. It's also critical to use oil, not grease, otherwise you will make things worse, not better. I don't think you have a problem with your servo IC.
Dear Valentin. Thank you again for detailed reply. I have changed all rubber capstans and two belts. Now I faced another one problem - little bit sliding of idler that responsible for play - the smaller of two idlers. All rubber capstans and belts were bought from Marian. There was no problem in unstoppable (crazy) running of motor. There is no super wow&flutter. Maybe servo is undamaged. I applied wrong way just for second or two. I dont know - maybe its undamaged by unknown reason. I have added photo how I applied correctly power box and when incorrectly. May I ask you a question regarding rubber idler of play? May I need to clean them after replacement? I saw in one video that person after replacement - cleaned them with isopropil? Maybe little sliding of idler is the cause of too smooth of it? Thank you very much. Vlad And thank you very much for link - I'll definitely read it.
Oh, I see how you placed the battery holder now that you put pictures. You would have to keep it in a strange position to make contact with the terminals, as they're designed to make contact only when the holder is in the correct position. However, it is possible that if you only touched for a few seconds no damage has been done. Batteries have lower voltage and lower current capability than a power adapter, so in theory the chance of creating a damage in this way is a little bit lower. I don't understand what is the problem with the play idler sliding... If by that you mean that it moves back and forth a little bit, that's normal as both the table reel "pulley" and the idler itself are not perfectly round. It seems that you use a translator to translate in English... If so, please try something different, as it doesn't do a very good job and what you say doesn't entirely make sense.
Dear Valentin. Thank you for reply and sorry for little bit difficult English. I know that my explanations a little bit difficult to understand due to lack of knowledge of theory in cassette players. So, finally my friend helped me and did a tech service and it seems it works well know. Thank you very much. Kind regards. Vlad
