Hi there! I'm fixing up my old JVC 838 boombox, and I have some bad variable sliders. I've googled the part numbers and didn't have much luck. Can anyone recommend a place that might sell them? Thanks!
JVC 838 - Variable Sliders
- Thread starter 2001SpaceOddity
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Hi, have you tried deoxidizing them? Few weeks ago I acquired a Nordmende RK 4186, which is basically the same machine, and the various sliders were scratching, I simply deoxidized them with the spray that I use in these cases (Teslanol, but every deoxidizing spray will do) and now they work fine.
Good work and have fun!
Good work and have fun!
yup - I tried Deoxit and didn't have any luck. I'm hoping there's a replacement part I could use, even if it's not OEM
Well, to be honest when selecting "manual" recording level the right channel is muted (all is ok when selecting "auto") but I don't think the sliding pot is to blame, didn't figure out why it behaves like this yet. Have you got any ideas?
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According to the service manual you need a slide fader that satisfies all of these specs:
B20K - 20K ohms with an "audio" taper (B-curve)
Duplex - contains two channels in a single package
Midpoint tap - has an extra pin for each channel that taps into the halfway point, allowing for boosted bass on the lower half
Length - 65mm? I don't own an 838 so that's a guess based on other posts. Something shorter could work but the pins on one end won't line up on the board, meaning they'd have to be jumpered. And since those aren't anchored into the board you'd have to glue down the fader. The tab length would also need to be close so the knob can fit.
The combination of 20K in a B curve taper *and* a midpoint tap is basically unobtainium, let alone one that's duplex. The only OEM ones I see for sale in duplex style with a midpoint tap are 250K with a W curve and are too long.
Your best bet is do what you can to fix the one you have. You may end up waiting years for an 838 to be parted out, and still has a good fader, and be lucky enough to be the one that gets to it first. JVC did use similar volume faders on their R-Kxx tuners, but the resistance is way too high (250K).
B20K - 20K ohms with an "audio" taper (B-curve)
Duplex - contains two channels in a single package
Midpoint tap - has an extra pin for each channel that taps into the halfway point, allowing for boosted bass on the lower half
Length - 65mm? I don't own an 838 so that's a guess based on other posts. Something shorter could work but the pins on one end won't line up on the board, meaning they'd have to be jumpered. And since those aren't anchored into the board you'd have to glue down the fader. The tab length would also need to be close so the knob can fit.
The combination of 20K in a B curve taper *and* a midpoint tap is basically unobtainium, let alone one that's duplex. The only OEM ones I see for sale in duplex style with a midpoint tap are 250K with a W curve and are too long.
Your best bet is do what you can to fix the one you have. You may end up waiting years for an 838 to be parted out, and still has a good fader, and be lucky enough to be the one that gets to it first. JVC did use similar volume faders on their R-Kxx tuners, but the resistance is way too high (250K).
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