I'm not even sure of the right words to describe the problem I'm having, but maybe (hopefully, please) someone will be able to help me. My walkman is a Sony WM-F17 that I got at a thrift store, and ever since getting it it has played tapes slowly. I thought it was just the belt, so I replaced it, but that didn't solve the problem. I know you can adjust the speed on a walkman, which is what I want to do, but I can't seem to figure out how to do that. The manual I have is honestly not helpful, the pictures are such bad quality that I don't know what part of the machine they're depicting half the time and I can not find the part that's supposed to adjust the speed. Also I'm having another issue, that might be related but honestly I don't even know. Basically when there's no tape in the player the motorized knobs, the ones that go in the cassette holes and turn them, (I don't know what they're called but hopefully you know what I'm talking about?) spin fine, obviously I can't tell if they're going the right speed when nothing's playing, but they look right. When I press rewind and fast forward they do that too, just like you'd expect them to. But when there's a tape in the machine everything goes slower, and the knobs barely turn when I hit fast forward and almost not at all when I hit rewind. I'm not sure if that is something that would be fixed with the speed adjustment or if something else entirely is the problem. Please help, I really want to be able to use this machine but so far it has given me nothing but frustration. If anyone has any idea what's going on I'd love to hear it.
I hope somebody who has direct experience with this model can help. Unfortunately I don't. Does this walkman have 2 belts or just one? Did you use the right size belt? Too tight or too loose will both make it not playing correctly. What you described, without tape running okay but with tape not, that indicates wrong belt. There could be other reasons, but this would be the most common. Pictures will help.
As it has been mentioned already, make sure the belt is the correct one for this model. I recommend this one: https://www.ebay.com/itm/323763693329 Then the problem with playing slow can be caused by a couple of things, some worth looking into first are: - are there any idler rubber tires in the mechanism ? If so, those can loose grip and the result will be decreased torque. This will only cause a FF/REW problem and a tape eating problem during PLAY, but won't change the speed in play. If that's the case solution is to either sand them or replace with new ones. - are all the mechanism's rotating parts turning freely ? Old grease can cause some parts to turn very hard. The service manual can be found here: https://elektrotanya.com/sony_wm-f17.pdf/download.html At page 6 of the pdf you have a picture of where the speed adjustment trimpot is. By the looks of it, should be accesible from the battery compartment without even removing the cover. Note that if you are using the correct belt and everything is turning freely in the mechanism (this needs to be checked, you can't assume it), tape speed (during playback) shouldn't need any major adjustments if it hasn't been misadjusted by someone else. The "knobs" you're reffering to are called table reels.
If the old belt turned to goo, you have to look very close for tiny sticky pieces around any rotating parts. Cleaning can take forever with IPA and cotton/foam swabs but might help with speed issues. Always try a few cassette tapes, sometimes the tape shell can be the issue for other multiple reasons. If you put your finger on the reel hubs spinning, do they stop with little tension or does it take some effort. An old dried belt (that might be new) might be slipping too much, it happens a lot, I've got a box of NOS belts but they're 18+ years old at this point.
