I'm trying to fix up my dad's old WMDD. Thanks to mihokm's amazing work, I was able to swap out the old broken center gear for a new one. The thing unfortunately still doesn't turn. I need some help figuring out what's wrong, and I was hoping someone might be able to point me in the right direction. Here's where I'm at so far: I've cleaned all the old battery corrosion off the battery contacts. (One of the wires came free of its solder on the battery housing, but I stuck it back there with electrical tape for now.) I plugged in a couple batteries and grabbed a multimeter to measure the power wires on the main board. There was voltage down on the other end, so I'm pretty sure batteries aren't the issue. Mihokm's guide pointed towards the servo controller IC as being a likely culprit for the unit not working. I tapped around on the contacts with my meter, and everything on it came up with a 0. I don't know if my hands are steady enough to solder that tiny IC. Either way, I would really like to know for sure before I look into replacing it. Is there anything else I can check to rule out other problems?
Please post some photos, there might be something visible, your issue could be a lot of different things. The owner of the forum has done a servicing tutorial for the WM-DD on his own website http://www.walkman-archive.com/articles/sony-dd-repair-guide_01.html I've posted several magazine articles on troubleshooting cassette decks in the Boombox Tech Talk Area, here's one, there's also an article on motors in this thread. http://stereo2go.com/forums/threads/servicing-cassette-decks-electronics-australia-1986.4711/
