I have been servicing my collection of Sony Walkmans for some time now. I replaced the belt and all the capacitors on my DD10. The audio sounds as it should again. However, there's one strange problem: I have to quickly press the play button twice to activate the Walkman. Pressing it once isn't enough. It's not the switch, because bypassing the switch with a test cable has the same effect. It's the white switch in the middle bottom of the PCB If the player works and I unplug the power cord and plug it back in, the Walkman starts playing immediately. Does anyone have any ideas what could be the cause of this?
I removed the switch and, with a test cable, short the two contacts on the print board. When I tap once, the motor does not start. When I tap two times (quickly) the motor runs. So it has to be an electrical issue. I replaced Q301 and Q302, but no effect.
What happens if you remove R305 from the circuit ? What about the power LED, does it remain on even after 1 press ?
Doesn't the DD10 also have CX20084 servo amp (IC601)? Have a DD3 here that also starts running when inserting batteries and i'm afraid that the servo amp is busted but haven't done measurements on the surronding transistors. IC601 controls if the motor starts running through Q601 2SB798. My first guess is that IC601 is on its way out, check the if the voltages on all pins are as stated in the sm.
I soldered the C309 on the wrong place. (My DD-1 print deviates from the schematic I have) I soldered it on the right place. Now the WM functions perfectly!!
