Sony TC-352D Speed issue

[Technics101]

I fixed this machine earlier this summer and was working perfect. New run stop cap, cleaned and re-lubed. The other day my nephew was over, and I wanted to show it off to possibly spark an interest. I wound the tape, started it. It played fine for a few seconds, and sped up to fast forward speed while lever was still in play. Is this a faulty run stop cap, or something else that’s going wrong? Edit...Now it only runs at fast forward speed in play mode. I’m almost certain it’s the run stop cap. I bought mine off eBay for around 8 USD. Could it just be a one off bad cap, or should I stay away from buying it on eBay?

 

[audiojones]

It's not going to be the motor run capacitor causing your problem, it sounds like the pinch roller isn't fully engaging. The pinch roller on this machine is supposed to pop up and push the tape against capstan shaft when you shift into the play mode and retract out of the way when you shift the machine to stop. If the pinch roller isn't engaging properly the tape may derail and run away after a few minutes or run at full speed right from the start.

The grease on the linkage is probably dried out and sticky, causing the pinch roller linkage to hang up. Tape could be skewing off the track too, take the head cover off and watch what the tape / pinch roller does when you put the deck into play mode.

 

[Technics101]

It's not going to be the motor run capacitor causing your problem, it sounds like the pinch roller isn't fully engaging. The pinch roller on this machine is supposed to pop up and push the tape against capstan shaft when you shift into the play mode and retract out of the way when you shift the machine to stop. If the pinch roller isn't engaging properly the tape may derail and run away after a few minutes or run at full speed right from the start.

The grease on the linkage is probably dried out and sticky, causing the pinch roller linkage to hang up. Tape could be skewing off the track too, take the head cover off and watch what the tape / pinch roller does when you put the deck into play mode.

I got all that cleaned and re greased and it is popping up and pinching the tape as it should.

 

[Technics101]

Now it’s playing perfect for some odd reason. By the way, there are no oil tubes for this motor. Do I lube right next to the shaft or leave it?

 

[audiojones]

Now it’s playing perfect for some odd reason. By the way, there are no oil tubes for this motor. Do I lube right next to the shaft or leave it?

IIRC there is a hole on the front plate and a hole on back plate of the motor marked OIL where you put a few drops. The one up front is kind of hard to access, I think it's behind the idler wheel right next to the pulley.

Anyway, pretty much the only thing that can cause the tape to runaway at high speed like that when you hit play is the tape skewing off the path either because of the pinch roller not pushing it properly or some other tape path issue. You'll have to watch the tape path with the head cover removed as it plays, if it happens again you'll see what is happening there.

 

[Technics101]

Thanks a million audiojones! I finally found the oil hole and got it oiled. I ran it a bit after I oiled it, now I’ll leave it on it’s back over night.