I have two beautiful Sharp JC-K99 Piu Walkmans. One red, one blue. I didn't care much for this model initally but when I got one in my hands, I knew I had to have one each of the colours. The first one, my blue one is almost brand-new, only has ever so slight signs of use. Maybe A+ condition. Here's the results of W&F GUI and NAK T-100 Both say the speed is way too fast. However, W&F GUI can't show a proper 3000Hz reference result because the speed is way too far off 3000Hz. I only get a reading if I select 3150Hz (though the tape is 3000Hz, so changing to 3150Hz as a reference is useless). NAK T-100 reports the number as pretty manageable. Not low at all but not horrible neither. Audacity also shows that the right headphone channel isn't as loud as the left. So likely needs volume potentiometer cleaning and maybe new capacitor. However, the volume for this model is actually on the remote. There are no buttons on this device except the one to open the cassette bay. So I don't know do I need to open the remote somehow and would that really help the situation? It doesn't look possible. The motor of the blue one is also really loud when using RW/FF. This is not the case with the red one, which is whisper quiet. Here's the results from the red one. This one is basically BNIB and has never been played, came with all the accessories and the box and original manual etc. too. It's in S-tier condition and sounds really good straight out of the box. Audacity shows the right channel is still a bit low, but not as bad as the result on the blue model. Speed is pretty much just as bad as the blue and W&F is even worse on this one. So when opening both these up, what would be the first thing to do? I have two belts coming from Marians' fixyouraudio.com. Despite the speed issues and W&F something about both these devices sound REALLY good. The blue one was originally very quiet but flipping the 3 switches on the inside of the device back and forth suddenly the volume improved massively. Both devices also have some weird issue where if I press play, they will play for 2-4 seconds and then reverse the direction, then play for 2-4 seconds then change direction again etc. It tends to happen when the tape is all the way rewound. I think the motor isn't strong enough??? to turn the tape or something. Maybe the capstans are slipping or pinch rollers aren't making proper contact? I have no idea. There's no window in the device either so I can't tell what is going on. With the door open the Walkman does Play, FF/RW etc. and everything looks really smooth. The mechanisms all look to be working fine on both of them. EDIT: One important thing I forgot to mention. I am using the original rechargeable SHARP AD-B3 battery (similar to) which came in the box with the Walkman. I charged it 3 times. First time the charger took it to 100% but then putting the battery back in, it started from 50%. Did it again and it started from 75%. I don't have another small battery of this type (yet). The battery would be at least 34 years old. It does enough to power and test the device and despite the speed and W&F issues, both Walkmans sound very good. However, I wonder as the battery is so old, could the voltage have changed enough to cause the motor speed increase or any other weirdness?
So quick rundown/tl;dr of the issues. Blue Slight audible motor hum Quite noticeable lower audio in right channel Loud motor when RW/FF Initially had very low volume (solved by flicking around all switches inside device) Speed is 200Mhz too fast... and W&F is pretty high Red Slightly noticeable lower audio in right channel Speed is 200Mhz too fast... and W&F is pretty high Tends to want to get stuck in never-ending loop of not playing but constantly changing direction (blue also had this issue slightly) -------------------------------- Questions before I open the devices: 1. How to clean the volume potentiometer in this device? 2. These original belts are both working, but should I replace them with Marian's anyway? 3. What style grease should I use? 4. How can I tell if the clutch gear is broken? (Is that only to CP-E7/or is it what causes the constant direction change?) 5. Does anyone know what capacitors this model takes? 6. Is it normal that the external AA battery compartment for the JC-K99, won't work without an AD-B3 gumstick battery also installed? If I only attach the AA compartment, the device has no power unless it has a gumstick in it. 7. How do I open the remote up to clean/check it, is it even possible? 8. Anything else I could do to reduce W&F in this device?
1 & 7. Post some pictures of the remote. It must have a seam where it has clips, it's unlikely the entire assembly was molded and can't be opened. 2. If the original belts are not loose, keep the original ones. 3. For what specifically ? For shafts of rotating parts watch oil is to be used. 4. The CP-E7 I serviced had a very high w&f (0.7% WRMS) on FWD and a slight high frequency clicking noise. Judging by the w&f figure, incline more towards clutch gears being good. But unless you remove the clutch, it's impossible to tell the condition. It's the gear in the middle that is part black, part white. Keep you finger on the assembly while removing the cut washer, because if the small gear is broken, the clutch spring will tend to push everything up and all the parts will end up flying. 5. Judging by how slim the unit is, it's likely it has no electrolytic capacitors. CP-E7 for example doesn't have any electrolytics, but then the boards are differnt (see picture attached). 6. Don't think so. Probably the sidecar isn't making a good connection. 8. Check the condition of the clutch gear and eventually lubricate the motor + capstan bearings: https://stereo2go.com/forums/threads/how-to-lubricate-the-capstan-bearing.7260/. For the motor that's loud there's only one solution: to clean and lubricate its bushing. Motor is similar to these ones (https://stereo2go.com/forums/threads/how-to-diassemble-and-lubricate-sony-wm-ex-fx-gx-motor.7940/), but the PCB with coils is kept by some metal tabs (which need to be bent back) instead of glue. The erratic behavior of playing 2 seconds and reversing may be caused by a dirty FWD/REV switch. The microcontroller doesn't know which side it's playing, so it reverses constantly trying to find the position.
