Last month had plenty of time in my hands , more than I ever imagined or even wanted to have. So the best candidate to waste my time was to try to repair the black Sony wm-f5 that was mentioned before in these two threads : Who forgot to pull the batteries! What's the worst condition Walkman you've ever seen? Threads titles are already descriptive about the condition of this walkman ! In short , battery leakage affected a large part of the PCB , oxidized and/or completely dissolved PCB circuitry traces and , in some cases , parts themselves. This is a pretty rare black colored wm-f5 , its better to have a nice non working variety of a walkman in your collection than not having it at all but it is also a bit depressive . My motive behind the attempt to repair it was , if possible , to avoid this discomforting situation. Here is what I had to start with : A couple of years ago started to clean it to see how extensive the damage was : BACK IN BLACK Fast forward in 2020 , opened again the poor wm-f5 prepared that this was going to be a failure maybe an honorary one but definitely a failure. A large area just under the batteries was severely damaged , mostly power supply lines without many discreet parts so I thought that was a good place to start. After some examination , wire measuring cutting and soldering made the first test and saw the power led light , that was nice but also meant nothing. Next logical move was to see if voltage goes to the motor , result : voltage ok motor doesn't spin. BOSS FIGHTS If you are keen with video games you know that to move to the next (usually harder) level you have to win a boss fight that is intentionally hard , very hard or extremely hard . It is the time when fun and frustration blend so nicely ! Motor doesn't turn , time for mechanical inspection , results : motor stuck , center gear main shaft stuck , auto stop bearing stuck , drive disc shaft stuck , head moving base semi stuck , all due to extremely pervasive acid and eventual oxidation from the leaking batteries. All this made the cracked center gear just a routine observation. I dismantled everything, used WD40 , a lot of careful cleaning and managed to free them up except the center's gear main shaft , it was solid frozen , I couldn't flame heat it because it is surrounded with plastic parts fixed to chassis , lots of WD40 heated it with the soldering iron tip for a reasonable amount of time with no success. I knew that using pliers in a horizontal motion would not be wise because most likely the outcome would be just to unlock the center gear shaft from its chassis pressing. No choice left , at this point is where to be prepared for failure helps , 90% sure that the thin chassis will collapse I took a large screwdriver with a big flat tip and inserted it between the chassis and center gear , a steady vertical twist of the screwdriver and progressively increasing force it felt like it will soon blow to pieces and it did .Prepared to see the center gear and its main shaft still in one piece and the shaft broken off from its fixed position to chassis it was a real surprise that it came off intact ! The following picture may be more explanatory (Notice rust on the center gear main shaft) : NEXT LEVEL Back to the printed circuit board (pan intended) , now the motor is spinning freely . If you recall the power led lights , visibly a lot of circuit traces had been dissolved , started to measure cut and solder wires from bigger to smaller scale , retraced also some very thin paths with very fine wire . After rewiring everything that was visible it was time for a test. Fresh batteries , earphones , volume in the middle , hit radio power button and .... radio static ! (one channel) It's becoming interesting , radio static but not radio stations reception , what about cassette ? Plays : one channel only , head azimuth needs adjustment , tape speed needs adjustment , broken center gear gap too big that makes the walkman stop , when hitting forward button both spools spinning in opposite directions. The cause for the last one was a bend I made , during the center gear shaft works , to a lever with a spring action that pushes down a small gear when the forward button is pressed, all the above addressed comparatively easily including the center gear crack using two parts epoxy glue. As we see the pcb from above the right bottom side is occupied in general from the audio preamplifier and the left bottom side from the radio reception RF stages . After quite a few hours with the service manual in hand many micro pcb repairs the one channel only problem was two fold an easy one at the volume pot and the other one was a tiny 1KΩ smd resistor that it was reading ok but with wrong voltage value in the relevant transistor , this one almost drove me crazy because every part around was measured ok , the problem in the end was that the acid had dissolved the thin contact between the solder and the resistor and I was measuring with the VOM over the resistor edges and not the soldering points , eventually this resistor is the only part that was changed new in this repair , the volume pot along with some other parts in the description that follow were repaired. By now cassette plays unbelievably flawlessly , at that point I was certain some sort of recaping would be necessary but the sound was amazing at all volume levels. REPAIR PARTS OR REPAIRING PARTS ? Normally I would be very happy but although 98% game completion is great 100% is best. No radio station reception , how bad can it be ? Started with the usual suspect : acid that likes to eat copper, with the service manual started to measure every coil and tiny transformer , the outcome was two coils and one transformer had lost 10 legs in total from the acid ! It would be impractical or unrealistic to search for these parts, my best bet would be to find a donor walkman but that wouldn't make sense , in that case I should have changed the whole pcb , besides the term "donor Walkman" it sounds almost synonymous to "sacrifice walkman" to me. Managed to repair all of them with T1 to be a real challenge , radio works now fine , it might need an alignment as it has lost some sensitivity at the lower edge of the frequency bandwidth but nothing critical and I'm thinking not to press my luck much more . Volume pot disassembled : BATTLE SCARS My age makes jewellers eye magnifying glass mandatory for so many tiny wire soldering , got some nice sun burns in my face from the heat of the fine tip soldering iron also burnt my fingers a few times when occasionally was losing sense of the 3d space. PCB repaired : THE TORTURE This wasn't suppose to happen I had to fail remember ? For about 10 hours put it on work , used every button combination for the tape transport in a fast and slow pace , adjusting volume level all the time , even wear it listening to music doing other things moving around until the batteries become empty , in other words used it as a Walkman and it worked like a charm proving just what a brilliant and reliable design it is. DISCLAIMER This is not a repair guide , there are no hidden or otherwise optimistic messages it's just a happy ending repair story that I'm sharing with you because of that ! I was just lucky , it doesn't worth the effort except only for the fun factor , if there is a tip to share is that this is a marathon not a sprint , when fun starts being frustration just stop and start again when you feel like it. BONUS LEVEL So you read this far , thanks ! Here is a bonus ! Spending so many hours looking this walkmans PCB it became a very familiar picture in my mind . While I was browsing some walkman pictures from my archive , this very well known picture to me of this transparent WM-F5 was looking strikingly different , why ? Amazingly (and what an irony , it is transparent ! ) I had never noticed that its PCB is missing the whole audio section and parts of the radio section making this a non fully working model , build just to demonstrate, most likely in motion , its moving parts. Some info on transparent walkmans from my thread about them here from the old s2g forum.
I just got in from my buckthorn bonfire and working on getting a knuckle joint out of my car's front suspension, very similar to removing your center gear. I'm still massaging it with PB Blaster, I'm not much of a fan of WD-40, so tomorrow I'll work it again and hopefully it will pop out.. Your write-up gives me a lot of motivation, I opened a box of players and a handful have major battery damage, it's hard to even look at them, some I bought and some I put away with batteries in them, who does that? This is going to sound contrived but one of the players was a Sports Model, the WM-F63/F73 (with no damage), I love the Sports Models, I was thinking how cool these are but they don't get the same recognition as the other players. Thanks for posting, I pulled mine out and now I'm thinking it might be next in cue for, hopefully only, a belt.
I like the Sony WM-F63/F73 they are pretty reliable and as far as I know they don't have any particular issues except maybe radio/tape switches that seem to fail easily. Good luck with the joint knuckle .
Wow, what an amazing rescue! I've got a Sanyo with a similar issue, it's not a good model but I wanted to see if I could get it working again. I was going to directly wire to components by trying to follow the board layout, and you've inspired me to give it a go. Thanks!
Thank you mate , I saw your videos on YouTube and you're doing a great job , your enthusiasm is also inspiring and that is all really needed ! Subscribed.
Thank you Boodokhan , that's a very good question , actually WD40 can be very good or very bad depending on the way it is used. Let me explain , if WD40 is used to clean volume pots and similar graphite adjusters ( Balance , Tone , Bass etc.) simply it will destroy them as it will dissolve graphite , in these cases I use very thin silicon based oil. To the contrary I use WD40 to clean mechanical switches like Tape/Radio , Stereo/Mono , On/Off , rusted screws etc. and works much better for me than other switch cleaners. To this particular walkman I used WD40 exclusively for the mechanical parts (levers , shafts etc.) for its very good ability to react with rust to very tight places . When finished the remains of WD40 were cleaned thoroughly , most importantly the PCB , that is because I have observed (on a car) that if portions of WD40 remain on paint for prolonged time it has a dissolving action , for that reason on a walkman or boombox , thorough cleaning is a safety measure . PCB and copper lines were cleaned with other more appropriate solvents , WD40 is not great at that. All in all WD40 is like a tool , it must be used appropriately , for example there many types of screwdrivers but for a particular job is used the right one. It is important to keep in mind that WD40 is extremely flammable so make sure that there are NO voltages that can cause sparks wherever is to be used.
absolutely fantastic job, mate next time instead of "WD40" try "Ballistol" - much better (and smells better)
