WDBURNS%MTUS5.BITNET (William D. Burns) (02/06/91)
Greetings all, I have a Sony WM-AF64 Walkman that has seen a bad day. I don't know how this happened, but all of a sudden it's playing tapes at ~ 3/4 speed. The LED power indicator reads OK and exhibits this behavior while on batteries or plugged in to the AC adaptor. I called a home-town "fix-it shop" and they would have to send it away (i.e. BIG money to fix). I can buy the tech manual for $30-40 but I was wondering if someone out in net-land has any experience with this particular model and/or is willing to send me a copy of the point-to-point schematic diagram for this little guy. It seems to be a problem with the power supply to the DC motor but without a diagram, I'm a little lost dealing with all those tiny, surface-mount components. Also, do these things you striaght DC motors or some sort of servo motor? I am studyiny electrical engineering so feel free to be as technical as you wish. Any help would be apprecicated, |\/\/\/| /____________________________________________________________/ | | /____________________________/ / | (o)(o) /William D. Burns / InterNet: / ( _) / (906) 482-FIXX / WDBURNS@mtus5.cts.mtu.edu / | ,___| /____________________________/ Bitnet: / | / / Michigan Tech University WDBURNS%MTUS5.BITNET / / \ /____________________________________________________________/ /______\ (funny, one-liner here..) ------ Posted using NetFeed, THE Macintosh <====> UseNet Interface Program ----
tf0z+@andrew.cmu.edu (Todd Andrew Ferrante) (02/09/91)
This sounds like a problem I had with my walkman (different brand). It seemed to be playing at a slower than normal speed for no particular reason. I thought it might be the fact that I was using rechargable batteries, but the problem persisted when I rigged up a 3v dc power supply from an ac adapter. I ended up opening the case and found a tiny potentiometer that was for the purpose of adjusting the motor speed. This pot is accessible through a hole in the back cover with a jewlers screwdriver so I won't need to open the case to adjust the speed again. I adjusted the speed until I thought it sounded right, but the most accurate way to do it would be to make a cassette tape recording of a 1khz sine wave from a function generator and play it in the walkman. Observe the audio output on a scope and adjust the motor speed until the output frequency matches the frequency you recorded on the tape. Todd Ferrante