I recently bought a non-working Wm-50. Having cleaned up the goo of the old belt I replaced it with new and gave the circuit board a thorough clean but didn’t replace any other parts.The mechanism is almost identical to that of the Wm-30. I tested the play, rewind and fast forward and all worked - but only for a period of around 3 or 4 seconds and then the motor would stop and the power light go off. After each operation I pressed the stop button and the play, rewind and fast forward functions would again work - but again only for 3 or 4 seconds. I repeated the sequence with a pair of headphones in (in case there is a power save switch in the headphone socket) and with a cassette in place with the same result. I checked and cleaned the two leaf switches but they were connecting as they should. I checked the connections to the motor and all seems well. If there was a loose connection somewhere I wouldn’t expect the motor to start up consistently every time after I’d pressed stop then either play, rewind or fast forward. Any ideas?
Oxidized leaf switches are a common problem on these series, starting from WM-10 up until the WM-100/200 series. Many times the only solution to this is lightly sanding the contact points with 1000 grit sandpaper. Your symptom is typical of a leaf switch contact problem. There is no switch in the headphone jack, that only existed in the WM-(F)10/20, none of the later ones have that. @Mister X Please move this to the Walkman section. Also there's a second identical thread here: https://stereo2go.com/forums/threads/walkman-wm-50-power-cutting-out.11175/#post-91300
Hi Valentin, apologies for double posting and compounding that by posting my thread in the wrong place. Thanks for your advice. I’ve tried sanding the two leaf switches but to no avail. I’ve checked the connections to the motor and can’t see any breaks in the ribbon cable. Im flummoxed! Mike
You stated in first post that power LED also goes out, case in which there's no reason to suspect the wires going to the motor. Rather it's a main power rail problem, could be related to battery terminals, cracked PCB you name it. Best approach is to check with the multimeter where the power gets lost. Assume you're not talking about the auto-off function kicking in ? This stops the motor after 4 seconds or so if takeup reel is not spinning. This only works in FF/REW and also the power LED would remain on even after the motor stops.
Hi Valentin, Thanks for your reply. It’s definitely not the auto-off function as the power cuts after a few seconds when play is pressed as well and when a cassette is in the deck. I will follow your advice and inspect and test the pcb. Thanks again for your help. Mike
Mike, I had a look at the WM-50 service manual and I think it would be useful to establish exactly where the power disappears, as mentioned by Valentin earlier. S301 is the POWER leaf switch and S302 is the FF/REW leaf switch. Since both the motor and BATT LED go out, I would first monitor the actual 1.5V supply while the machine is running. If the 1.5V at the battery terminals remains present when the machine stops, measure both sides of S301. Sanding the S301 doesn't necessarily rule it out. If S301 remains closed and the raw 1.5V supply is stable, I would then trace the switched supply around Q305/Q306/Q307 and the AUTO OFF CONTROL section. I would also try powering it from a regulated 1.50V bench supply. Service manual specifies about 70mA in PLAY and 85mA in FF/REW, so watching both voltage and current could help. This should tell us whether this is S301 (power) related or auto-off circuit.
