Jonny electronics: the tape project

Some detail pics. See how the door opens and slides back. That’s a really cool feature.

It was missing a few screws and the right hand hinge was a bit vague. I tightened up the remaining screws and it then wouldn’t clip closed. It’s been dropped a number of times and I’m pretty sure the hinge is bent.

Some slight technical hitches.

I thought, actually, I wonder how much these machines are on eBay for spares or repairs. Turns out, not much for a scruffy one, even shipped from Japan. Then I thought, my one is really bashed on one side; what if I found one which was cheap because it was bashed up on the other side to mine, but good on my scruffy side. I could then take the cosmetic bits I need and the bent hinge and make one good machine.

So that’s what I did, and found one in Japan for not too much. It arrived 48 hours later with all the bits I need. It also seems to work apart from a snapped drive belt...

But. Have a look at that pic of mine a couple of posts back with the door open, looking straight in at the head. There are a few bits snapped off. Probably the most importantly bit is one of the cassette locating pegs is missing. That’s probably why it rolls something chronic. Additionally the Dolby NR switch on mine is broken on the pcb and is loose. So I think what is more likely is I’ll use mine as the parts mule to make one good machine out of the new Japanese one.

It means the little dream I had of resurrecting my own machine with donor parts is now that it becomes the donor, but at the end I still get a restored, working machine and mine still gets to live on albeit in a slightly reduced manner.

These were the tools I was working with. Trusty 25W Antex iron and stand from around 1996 and a roll of solder liberated from school. Actually quite good miniature screwdrivers and a desolder pump.



Also bought some undeniably Chinese quality tweezers. My good ones were stuck at work due to lockdown, but for £2.99 delivered they’d do the job.



That meant I could get to the bits underneath this:

New belts on. One of the problems I had where I was working was a combination of poor light and my eyes aren’t as good as they used to be, so I couldn't really see what I was doing. I actually used this image to zoom in and see if the belt was twisted. It was.





I repeated the process and it seemed to be good that time:





That meant I could start to put it all back together. Motor magnet cover and clip back on, reassembled, re-soldered the joints and...

I'd done something wrong. The belts seemed to be doing their job. The new clutch plate I wasn't sure about. It kept changing direction and there was no sound. I might have wound the mechanism round too far when putting the belts on and maybe slotted a microswitch in the wrong place. That meant I'd have to take the board back off to see.

That basically brings us up to date. Family life during lockdown got in the way and I shoved everything in a bag in my drawer and basically forgot about it until today. Randomly, a Sony Walkman stripdown popped up on my Youtube feed and it reminded me I hadn't got this working. Now I'm back in the lab I have the perfect place to work and all my tools, so it's time to dig it out and have another go.

Lunchtime antics tldr: Noted a few things from that ^ video. Assessed state of where I had left off. Refamiliarised self with innards of machine. Found sticky pulleys. Felt that the gears were too tight and oiled some stuff. Got oil in too many places...

The sticky pulleys. The solder points on the PCB were already unsoldered, so all I had to do was fold it back out the way. First thing I did was tried to turn the mechanism. It was immediately obvious that the drive belts were stuck to the pulleys. Like this:





If I tried to turn the motor, the belt was just stuck in place and wouldn't go round. As you can see in some of the previous images, the top of the motor lifts off and you can get the belt back off. The pulleys were all completely gummed up with sticky residue from the old belts. I got as much out as I could with a tiny swap on my tweezers and isopropanol.

Additionally, I felt the whole rotating mechanism had a bit too much resistance which might explain why it kept swapping direction. I tried to ease this by applying a bit of light oil to the axles and gear teeth to soften up any old grease that was on there. It seemed to help a little, but then it was clear that some had got onto the pulleys and now the belts were slipping. So apart it all came again (the top of the motor is a proper curse word to get off) and that was kind of the end of lunchtime. I think I'll leave it overnight and carefully degrease the pulley grooves tomorrow or next week. With a bit of luck the oil will do its job where it needs to.

I had a chance to look at this on Friday before I went home. I mentioned the mechanism felt like it had too much resistance - to check this I popped the silver one open and compared the resistance on the pulleys. They had almost nothing, so that was a good starting point. I narrowed it down to these two, middle and right:



I was hoping to be able to lift them off, somehow, to clean underneath where there's probably hardened grease. You can see the black gear has two tiny clips on it. It slides down the shaft and snaps into place. I don't think it'll come off again without breaking the clips. The brass one has the capstan on the other side and seems to have a push fit washer with a tiny circlip underneath it. I can get the washer off, but the circlip is too tiny to get even my small tweezers on. I suspect when it was made, the circlip was pushed down over the capstan shaft until it snapped into the groove.

I really needed access to both sides of the mechanism. On the more basic models you can do this by just taking the door off. On this one, because of the sliding door mechanism, the door and hinge restraints are spring-loaded and it all tries to fly apart when the screws are out, plus the sliding mechanism is a nightmare to realign. I'd tried to avoid taking it off. Instead of trying to fight it, I took it all off at the hinges and removed the door and head mechanism completely:





That let me twiddle about with the gears from both sides, hence working out that it was those two gears causing the tightness in the drive. I gave them a damn good blast out with isopropanol and they loosened up significantly. Figuring that there was probably still a bit of waxy grease trapped underneath, I then decided to try and wick some light oil underneath the gears, in the hope that the oil would work its way in and keep the grease soft once the last of the isopropanol had evaporated.

Many of the videos I've watched about fixing the belts on these have ended with players that run too slowly or have a lot of wow/flutter. I'm willing to bet that it's caused by these two gears running too tight, so hopefully mine won't do this.

Because it's all spring-loaded, the hinges fought me for at least 30 minutes and I was about to start shouting and swearing at it. Eventually I managed to get everything to align, though, and got the screws in.



That's where I left it on Friday. Annoyingly, it was quite tight again when I checked it this morning, but nowhere near as bad as before. It needs a little bit more work, but I think it's close now.

I also found this little fella in a blob of grease in the bottom of the door:



It's about 3-4mm long and I don't recognise it, so I'm hoping if I ignore it long enough I won't need it.

techmoan would be proud

couple of my tape players
got several car ones, 3 boom boxes, and 3 hifi tape decks

I used to get through cheap walkmans at an alarming rate, then when Dixon's were closing in my town I bought my first Sony one, that thing lasted for years, it might still even be in my folks loft. I should go and dig it out.