Hello Everyone! I need a little help to my WM-DD3. After the broken center-gear and capstan idler replacement (of course i clean it everything and oiled it, all shafts and contacted areas), i try to adjusting the w/f and of course the tape speed. Sadly the w/f is so high 1,5%(DIN) and the tape speed running down at the end of tape to 2950Hz (3150Hz with ref.tape) Firstly i disassembled everything once again, every gear is rotating freely and its totally noiseless, check the capstan and pinch bearings are fine. I change it the CX20084 IC for a new one. Assembled it i measured the following values: X601:27,7kHz IC601 4pin: 867Hz FG coil resistance 7kOhm (so it's not open) Motor current freely, feed 1,45V, not contacted to idler: 25mA Motor current freely , feed 1,45V, contacted to idler: 55mA Motor current solder to main-board feed with 2,5V in DC IN socket without cass: 85mV Motor current solder to main-board feed with 3V in DC IN socket without cass: 100mV Motor current solder to main-board feed with 3V in DC IN socket with cass: 120mV voltage 1,75V on motor terminals Torques: Take up 35g-cm, back tension 2,5g-cm Pinch roller pressure: 140g (i try to increase with push of my finger, issue is the same) So i think the source of the problem is not mechanically, it's coming from another way. Maybe some caps or resistor are get down? Thank you for any advices! Norbert
Aaaaand it's solved! The DC-DC converter's Zenerdiode need it a little heat, reflow it all SMD transistors, and polished it the power switch and now it works fine!
Nice work megott, some of your tests are above my tool-set, usually I just do basic tear-down, clean up and replace wear parts with soldering if needed. I'd love to see photos of how you do some of your testing like the torque and roller pressure.
