Bought a WM-2 listed with "no power". Found out quickly that some wires had disconnected from the battery contact, shouldn't be too big an issue soldering back together. Problem is HOW, there are two disconnected wires, black and white, and I assume they both belong to a single battery contact on the right because the left contact already has a wire soldered to it. Not to mention the blue stuff which I assume is dried up battery acid. I want an opinion from someone who's worked on this model specifically on how to approach this. See attached photo.
I attach a picture of how the wiring is done. The 2 batteries are wired in series (to have 3V), so there is one black wire that goes from the negative terminal of one battery to the positive terminal of the other battery. The positive terminal (the one that is not connected to the other battery) needs to be soldered on the PCB near the + point I marked on the picture. The negative terminal (the one that is not connected to the other battery) needs to be connected to 2 points: - one is on the DC in jack, marked with - in the picture. - one is near the jacks, connected to one side of C306. Do note that the particular colors marked on this diagram may or may not correspond with the actual wire colors used in your unit. From the little I can see in your picture I believe the black wire is the one going to the minus of the DC in jack, while the white one is likely the one going to or coming from C306. Really hard to tell exactly since your picture is cropped. Main idea is you need to connect them as on the diagram, the colors of the wires are not important but HOW they are connected. The blue stuff must be cleaned before re-soldering the wires. The negative terminal spring should be removed from the case and cleaned while the wire might need to be cut a bit if the copper is corroded. Also do note that the soldering must be done with terminals removed from the case, otherwise you will melt the plastic case from the heat. I have some pictures with the WM-2 wiring from a repair, but I can't find those at the moment. However, what I provided is enough to do the repair.
Hello, thanks for the detailed response! I want to clarify real quick that yes, the aforementioned grey wire does indeed lead to that C306 region or thereabout, just like the diagram. I have used this very service manual while planning a repair approach so rest assured, we're on the same page! While awaiting responses I've taken it into my own hands, see how good/bad I could possibly do. Since creating this thread I've removed/cleaned the battery contact spring. I did keep in mind to attempt soldering the contact while removed from the case, but your thoery about copper corrosion is unfortunately true, when attempting to skin the wire the copper came suspiciously easily. This unfortunately means I'll have to outright replace these wires. Maybe you could give me a recommendation of the kind of wires I can buy today that suit that specific need? On another note, after studying the diagram it shows that both the black and grey wire have to be soldered to the contact but I'm not quite sure how. Let's say I intertwine both wires at the tip and solder that joined tip to the contact or just solder both wires to the contact one by one, or can I do either? Thanks!
For the wire I recommend 28-29AWG wire for replacing the existing wires. The exact diameter isn't critical as the current consumption is very small. About the gray wire connected to C306 I would not connect it to the spring but rather to the DC in terminal.
28-29AWG, noted. Attached is a more expanded photo of the unit. The gray wire I'm still confused about since according to the diagram it should be connected to the contact just like the black wire. I'm mainly curious about WHAT the gray wire does if you're suggesting to connect it to the DC-in terminal. Got a side question too that you don't have to answer, its for cosmetic sake: I have two of this unit. This US one with just the "Walkman" logo out front and the Japanese "Walkman II". I'd like to swap the front end of this US one onto the Japanese one because I prefer the cleaner look but the Walkman 2 has a black wire soldered to the volume wheel PCB and taped to the front casing, while this model doesn't. Do you know exactly what THAT does and if its possible for me to basically swap the front ends of both? Thanks again!
Looking at the schematic I think there is an error in regard to C306. I think this is an intereference supression capacitor going from the negative side of the headphone jacks to ground. The way it's shown on the schematic would indicate both sides of C306 are connected to the circuit ground, in which case the cap would do nothing. That's why I think there is an error. Ideally, this capacitor should be connected directly to the battery terminal (as shown in the diagram) to avoid picking up any potential voltage noise developed on the resistance of the negative wire (the one connected from battery negative to DC in jack). However, in practice, the resistance of that black wire is really small and don't think it will matter if you connect it to the DC in jack or to the battery terminal directly. I also remember seeing it connected to the DC in jack in other units. Do how you prefer, it's up to you to decide. That black wire is for shielding the volume pot board and the potentiometer itself in particular. If you look at the PCB diagram you will see the 2 case pins of the potentiometer are connected to this black wire. As long as you keep this volume board paired with the main PCB/mechanism, I don't see a problem of swapping the front case. That is assuming it actually fits in the new case as far as screw and holding tab location. Can't remember exactly but I think the case is also connected to this ground through the screw. So as stated above, if the small PCB does fit, there's not problem as nothing will actually change. If you need to swap the PCB then it's a problem. Not having this ground connected to the main circuit ground will make the unit prone to picking up mains hum. You can, however, add this ground wire yourself in the case you do need to swap the volume pot PCB. Feel free to ask more questions if there are still unclear things.
Hello again! I've been travelling so I don't get much time to reply but I can kinda understand what you're saying. I have one more thing to clarify before attempting the repair. If you see the attached photo in my previous reply, you'll see exactly how the grey wire is supposed to be positioned, at least according to the diagram. The solder of the grey wire's end attached to the PCB is partly green and maybe looks to be corroded, does this mean the cap leaked and needs to be replaced ALONGSIDE the wire? If so, what cap would I need exactly?
In regard to the gray wire positioning, I already answered your questions so won't go back to that. Looking at the last picture indeed I can see something green. However from the picture it looks more like a paint mark to mark that point than leakeage. Ceramic capacitors (C306 is a ceramic capacitor) don't leak as there's nothing liquid inside. Besides, if some adjacent caps were to be leaky, I would expect a lot more than one and I can't see any other spot on the PCB with corrosion. I think you should proceed in doing the repair of the wires and then test the walkman. If you find something off, you can always ask further questions. I also suggest to not quote previous posts and simply type your response in the box below press "Post Reply" rather than using the "Reply" button which automatically quotes the post you reply to. There's no need to quote a post that's just above your own as you're adding the same information a second time.
Copy on the quote-reply thing It's my first time ever using an online forum of this format. Good to know though, I've heard of capacitor leakage in models like the WM-5 which was basically a souped up WM-2 so I was hoping the WM-2 wasn't prone to that too. Alright then, I'll perform the repair as soon as I get the chance and update accordingly on my issues. Thanks for the help!
About capacitors, it depends on the brand of capacitors fitted, but I can't remember seeing any WM-2s with leaky caps. The WM-5 is indeed prone to capacitors leakeage. While the WM-2 and WM-5 are similar in many ways, the PCBs are entirely different (not just the layout but the parts): the WM-2 uses 2 x CX808 ICs, while the WM-5 uses 1 x CX887 IC. Brand of capacitors used is also different, the WM-2s does not use CE brand capacitors (which is the brand that leaks). It would be visible if caps were leaky: green residue on capacitor legs (visble on component side), solder on pads won't be shiny anymore (this is the most obvious tell-tale sign), discoloration and exfoliation of the green silk screen of the PCB in leaky areas.
Hello @Valentin , I have another question though unrelated to the WM-2. I have a TCM-100 (TPS-L2 predecessor) that automatically dislatches the play button sometimes. I opened up the unit thinking it was an issue, but turns out there are plastic pieces inside that touch each other and basically do nothing when they touch each other, except when timed perfectly they push each other apart and that causes the play button to dislatch. No parts are damaged/loose afaik and it seems the plastic pieces are only placed so closely to each other to CAUSE that occasional dislatch. I'm curious if this is intentional/by design to avoid timing problems or something because I'm considering snipping a piece off to stop the play button from dislatching. If it really is by design, I'm curious on the WHY and what will happen if I do end up cutting the piece off.
@sirwalkboy Please create a new thread (in the Walkman --> Tech Talk section) in regard to the TCM-100 problem as it's not related to anything discussed here. Also, please open the unit again and take pictures with what you describe as "plastic parts which touch each other". Without pictures I can't really comment on the problem.
