Oh alright, so I managed to power it by the AA adapter pins (the one closest to the battery flap is + and the other -) with my bench PSU injecting 1.2v@100mA and it powered on absolutely fine ! I didn't see any clock so I presume the button cell's just used to keep the radio presets in memory. (I did not find a user manual on the internet but honestly I think I'm spot on on this one)
Yes, those coin cells are always used to keep power to a volatile memory, as those have very little current draw (in the order of a couple μA) so these batteries will last for years. In your case it is obvious that if you don't have a clock, it is for the radio presets as you correctly said. Btw, You will need a new pinch roller (both should be replaced) and that rusty capstan needs a very good clean. If alcohol alone does not clean it, use ferric chloride (avoid using sandpaper).
Do you happen to know the dimensions of the pinch rollers needed ? I'll try ordering some from fixyouraudio, I want to have the new ones when I take out the others, I'll get the belt with it, to be able to repair it completely in one sitting
If the FX70 is just an EX70 with radio, then this is the pinch roller that you need to buy: https://fixyouraudio.com/product/sony-wm-ex70-pinch-roller/
Well I'm back again folks. I ended up buying another 'faulty' one of these models on ebay again (£25 for this one), but from a different seller this time. This one is cosmetically better than the first one I got, but after getting it opened up I found it has the same issue as the first with a split ribbon cable. Interestingly I noticed that the ribbon cables in it are different to the first one (will try to put a pic up later if I remember) and the markings on the walkman are different slightly too, despite the same model number. The pinch rollers seem better on this one at least. When I close the battery door, it whirs for a couple of seconds and I think the direction mechanism switches once or twice (not 100% sure what it's doing but it's a slim metal plate along lengthways just inside from the hinged edge which seems to slide back and forth once or twice, then it stops again. I've done a belt bodge temporarily since the belt was in bits, so I took the somewhat slack belt from the first one I bought, and cut about 1cm from it then superglued the end together. It works enough to make it spin instead of slip at least for test purposes. So now I'm thinking as I have 2 of these, it might be worth actually buying one of those replacement ribbon sets, even though they're a bit pricey. Hopefully I could get one good working machine out of them at least. Concern there though is that 1) it actually has 3 ribbon cables and the replacement ones come as a set of 2..... and 2) no guarantee that fitting those would fix either of them. I think it's quite likely that at least one of them might be fixed with new ribbons, but I'll be a bit upset if I spend £40 on those and then it doesn't change anything obviously. It did also make me wonder though about the feasibility of trying to make my own temporary ribbon cable. So I'm off to look on instructables and google it. Wish me luck! *Edit - I found this sheet on Adafruit called pyralux which is like a sheet of ribbon cable conductor basically and in theory could be made into bespoke cables. I've got a laser cutter so am wondering if it would be possible to etch a ribbon out of it, but it's a C02 laser and I don't think it will etch/engrave copper even though it's obviously super thin. Shame as it would be fun to try making my own cable like that. I have some kapton tape for 3d printing stuff so I might attempt to make a ribbon using that and some tiny enamel strands of wire or something.
In regard to the ribbon cables, I think it's worth the effort to design them in a PCB CAD software and get some manufactured as nowadays the prices of manufacturing these are affordable. You can manufacture more and sell the ones you don't need as I'm sure you're not the only one having this problem. Getting NOS ones is not worth it in my opinion, especially if they're pricy. Read about the pyralux here: https://blog.adafruit.com/2015/02/11/making-a-flexible-pcb-with-pyralux-wearablewednesday/ It's not clear how easy it is to make a flexible PCB using this technique compared to simply designing one and get it manufactured by a PCB manufacturer. Certainly interesting as a technique, didn't know about it.
Thanks, yeah it did cross my mind about how much they might cost to have made, as I have used a pcb place in China before and they were super cheap and fantastic quality. Bit of a niche thing to try and sell to get money back though I’d expect. Could be worth a look still though. I might try to get a piece of that stuff though and cut the tracks with a scalpel and straightedge. I’ve got ferric chloride for etching but I can’t imagine being able to do it quite fine/accurately enough at home to suit these cables, but who knows. No idea if the ribbons found online are NOS or if they’re basically what suggested here, someone getting a load made and then selling them. All good for thought. I do have copper tape at home so I could try the scalpel idea on that I guess, then something tougher like kapton over the top.
Well well well! Lookie what we have here then! I just took both these units back apart a bit more. The original one to inspect what ribbon bit was broken and I’d tried to repair previously, and to remove the damaged ribbon from the new unit to inspect closer and see if I can do anything. So then I realised it turns out the snapped part on original unit was the biggest ribbon part with 8 terminals. And that one had 3 separate ribbons. The new one has two ribbons as one is a combined double ribbon (left part of pic), and the bit that is broken on the first unit is actually good on the new one (right part of pic)! I’ve done continuity test on both the good bits and appears all ok, so in theory at least, this means I have a fully intact set of ribbons when I remove the bad part of the combined one, and use the separate good cable off the old unit. Easier to show with a pic obviously but I’m prematurely excited about this now!
Well unfortunately this didn’t work. The 3 cables all now appear to be good and all have good continuity right through, yet the unit does display anything at all on the lcd display still. The only thing that creates any activity is closing the integral battery door with a charged gumstick battery inside. This causes the motor to spin up and things spin back and forth for a few seconds but that’s it. No button presses give any response or action except for the radio on button, which causes one of the red LEDs to briefly flash, and 4 rapid beeps are heard in the earbuds. Those are the only actions where I’ve been able to make anything happen sadly. I did also fit a fresh cr2016 battery too. I have tried this cassette door/front half/display attached via the 3 ribbon cables to both of the ‘transport’ halves of these 2 units. Same result with either except the newer one clicks around more when the battery door closes but they’re the same besides that. Tomorrow I’ll unsolder the ribbons and try them on the older face panel in case it’s bad somehow on this one I just bought. Are there any obvious and relatively simple things to check that might be preventing anything appearing on the display , or stopping any of the buttons really doing anything? Thanks
Is the older face place identical to the newer one ? Any small differences could cause it not to work at all. There is nothing on the display either because the microcontroller doesn't get into the right mode as pressing the buttons do not send the right signal to it (again that faceplate if it's slightly different can cause that), hence not triggering the internal interrupts necessary to activate the PLAY, FWD, etc. How are the buttons wired ? With pull-up/pull-down resistors and each read individually or a resistor ladder and microcontroller reads an analog value ? A picture with the front panel PCB would be useful.
I just checked mine, and the rev pinch roller is also dented. Looks like the exact same issue the DX100 has, when the mechanism does not return to center for some reason. While I had it out, it struck me as visually close to the Aiwa HS-JX70. Pictures to support my thought. It only shares 2 ICs, had to look it up: servo and remote comparator. Unusual for Sony but not for Aiwa, a TRRS connector for the remote is used for the EX and FX70 , also for the EX and GX90 and perhaps very few others. The EX55 though uses the rarer 8 pin green connector (like the 700 series, DX100 and a few others) but not the more common 3.5 jack + 4 pin (7 pin) green connector that was often used, also for MD remotes. Need to go through my box of really broken ones to see if I have a spare EX or FX70, although the ribbon cable will not be the same most likely. Edit: it is an EX70 with apparently some water damage, judging by the capstans. The ribbon cable seems to be intact though:
I tried the remote from the WM-EX90, and unfortunately it does not work with the WM-FX70 (except for audio pass through).
