Sanyo JCX-2400K FM Stereo Light doesn't work? Also looking for Original Manual

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Andy Lang

New Member
Some background:

I'm a vintage-tuner newbie, picked up a very nice JCX-2400K for 75 bucks on my local Craigslist as my first vintage receiver and first stereo since being in my own, having moved out for college. Having not had a whole lot of experience with vintage equipment like this other than working the FM dial back and forth on an old JVC my godparents had, I may be overlooking something.

Receiver sounds excellent, because of course it does! I got it hooked up and working the same day I picked it up. Bought a 50' spool of speaker wire at Fred Meyer for the speakers. The guy in the Fred Meyer electronics department told me they actually don't stock FM dipoles! Might mean a trip to Walmart just in case they have one.

But...with my about 30-ish feet of leftover speaker wire as a current FM antenna, if I pick the coil up in my hand the signal strength meter more or less pegs, a good 4 or 4.5 on a given station (just sitting on top of the unit, it's about a 2, and without any antenna it only pulls one station in clearly a 3Kw college station whose tower is a few hundred feet away from my location (I currently live in the dorms). With no antenna it pulls in several other stations audibly but not even enough to really make the signal strength meter move.

Now, to the point of the thread: Even with the signal strength meter at a good 4.5 picking up the coil of speaker wire I'm using for an antenna in my hand, or working the dial back and forth to try multiple different local, strong stations, I've never once gotten the FM Stereo light to illuminate. I don't really want to turn the thing up terribly loud, living in the dorms to get the full effect, but it sounds like it may be in stereo? I also know my speaker placement is far from ideal, held off the floor by paperback books. So in essence I'm not sure if it's in stereo or not. I've read having the stereo indicator burned out can force a receiver to stay in mono, is this true for my particular brand/model?

I'm just curious. It's not a big deal for me, and for the 75 bucks I paid for this vintage beauty which was gone through by its previous owner (dial lamps replaced, no scratchy controls, quite clean) I'm not at all disappointed. Do you guys think it's just my reception situation, speaker wire and a concrete building full of fluorescent lights? What's generally the minimum strength to get the Stereo light to come on?
 
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Don't see much on this receiver via Google and don't see much JVC here. Do you hear a difference in the sound going from Stereo to Mono? Could just be a burned out bulb, which is very common. It is also common for vintage pieces to need alignment.
 
From what I've read Googling the thing before I bought it but after I saw the ad this model is relatively rare, so in a way the lack of easy to find publications doesn't surprise me, though I would like to find the original literature that would have come with it for troubleshooting stuff like this. I do not notice a difference in sound going between stereo and mono, and with my speaker placement and background noise volume at most (living in the dorms and not wanting to annoy neighbors) it's hard to tell. But I think the indicator bulb may be bad.
 
Sanyo gear wasn't around long. Try a dipole antenna instead of playing with 30' of coiled wire. That's step #1. Then report back.
 
Hello Andy Lang. Welcome to AK. Looked up the Sanyo JCX-2400K on HiFi Engine.com . Found the JCX-2400KU. Just register and download for free. Hope this helps.
 
So, is it actually tuning in stereo, but the indicator isn't lighting up, or it it failing to tune stereo at all and "everything is mono" - which would also explain why the light isn't firing up.

I don't know your gear at all, but to me, if you're tuning in stations strong, a multimeter on the bulb leads should tell you whether power is being sent to the bulb (therefore you need a bulb replaced) - whereas if you aren't getting power to your bulb, it could be something else up to and including needing an alignment of some sort or possibly a repair.

My Kenwood KR-3200 had the same issue. I was getting power to the bulb but no light, I replaced the bulb, lights up fine. My KT-615 however, same issue - needed an alignment for it was having issues finding the pilot signal, therefore it'd tune in mono only.
 
Considering how old this thing is, it wouldn't surprise me if something needs adjusted. I did also notice that the higher up I go on the dial the more it's ever so slightly off. Case in point, I noticed that a station that's definitely at 98.1 and is tuned absolutely perfectly according to the tuning meter and at a full 5 on the signal strength meter (living maybe a mile from its transmitter) appears on the dial itself to be at about 97.9 or even 97.7.

Another thing: one of the channels (couldn't figure out which speaker was which and hooked it up in a hurry but let's call it Right since that's which side of the room it's one) sometimes would get weak intermittently. Adjusting the balance to that side seems to have helped, though, it hasn't done it since.

Other than that, she's a beaut, and sounds wonderful! I'd like to repair the minor issues but for now will live with it as is since it's a "daily driver", being my only receiver at the moment. Once I'm someday savvy enough and/or it develops more serious issues, I'll get it fully fixed.

I'm just so glad to finally have a vintage tuner, I've wanted one for years!
 
Look inside, take a pic, there are only so many ICs that do the stereo decode function.
Need to check if it is power, the lamp or the IC causing no stereo. really depends on how they designed the decoder. SDOmetimes ity can be IF or detector alignment too.
Do you hear if it is receiving stereo from the speakers or if it sounds like mono, if you toggle the mono switch on/off /
Make your own di-pole, out of old 300 ohm balanced transmission line, it is easy enough, if you can solder wire.
do not worry about the linearity of the analog tuner dial, you usually set them for 98MHz, and hope that they are close at the extremes :-)
DO not adjust things that you should not unless you understand the adj procedure.
 
I should not be adjusting things. LOL. I'm pretty new to this. I'll try some headphones, but need to find the proper adapter for a pair of modern earbuds first, that's all I have. Fred Meyer electronics department to the rescue I guess!

One other thing I never knew, on slightly weaker, not-quite-enough-to-peg out the signal strength meter stations, the signal meter will happily bounce back and forth with the beat of the music. Granted, some of the radio stations around here use weird modulation and audio processing.

Good to know about aligning for 98Mhz. At the low end, it seems perfectly aligned. Highest-in-the-dial FM signal here in my area is 105.9, so it's hard to really tell. On another station truly at 101.1 it definitely looks like somewhere in the 100s and not the low 101s. A station at 102.5 looks like 102.1 or so. 103.9 looks like maybe 103.5? And 104.7 looks like 104.3 or so. And 105.9 looks like about 105.5. So it seems like it's about 2 clicks off above 98Mhz. Now I almost want to go buy a small FM transmitter just so I can set it somewhere in the 106-107 range just to test how far it is out of alignment at the extreme high end. (There's stations at 88.3 and 88.7 and 89.1 and 89.9 for checking the lower end...

Going in the other direction, down the lower half of the dial: 94.3 appears on the dial as just barely not touching the 94 mark, maybe 94.1. 93.5 looks about perfect. You get the idea.

If anyone wants, I can make a video of going from one end of the dial to the other, signal strength and tuning meters definitely in view for proof that it is definitely fully tuned to the "center" of a station.
 
"the signal meter will happily bounce back and forth with the beat of the music."

This is an indication of multipath interference. The 2 channels arrive with a small time lag between them, hence my earlier advice to use an outdoor or attic multi element Yagi. Dipoles don't cut it in all situations. You probably need an alignment too.
 
So does that mean the receiver IS picking it up in stereo, or not necessarily? I'd I'm obviously quite new to this. I vaguely understand the concept of FM stereo, the receiver has to find the pilot tone...if it was not finding the pilot tone it'd be in mono only, right? I will say as a child I used to think the stereo light on car radios or home reviewers was broken when it would intermittently blink on and off with a weak station.

Big outdoor antennas won't cut it in my situation (currently living in the college dorms) but I'd like to move off campus (to an actual house, an apartment is a no-go) and plan on setting up a good Yagi in that case.

And not every station does the "dancing signal meter" thing, only certain ones; so multi path makes sense to me.
 
"And not every station does the "dancing signal meter" thing, only certain ones; so multi path makes sense to me."

This is normal. It's alignment time. DIY is foolhardy. You'll need a good FM signal generator & scope. Expertise & experience are very important too.
 
Definitely. It's honestly such a minor thing I'll live with it for now, although there is a vintage audio/record store in my area I'll go to and yack at them about places to have it done, just for the heck of it. I'd like to find something to take its place in the meantime while getting this one aligned; in a perfect world another identical Sanyo so someday I can have a parts unit once I'm experienced enough to do my own repairs; I intend to keep using vintage receivers my whole life, hopefully many decades still to come!

Suggestions on what to ask as far as looking for somebody who could align it, and what it would probably cost me? What's a "good" deal for getting one worked on by a reputable individual?
 
I understand the economic crunch of being a student & living with the problem for the pro tem. Be aware that you will need c. $500 or more for test equipment. In a major city, an alignment could run $150 to $200. Expertise & experience are most important. If you find a good repair station when $ permits, you can ask for an estimate. In NYC, that would run c. $75 which will count toward the repair if you give them the go ahead.
 
Lived in Anchorage for 1 & 1/2 yrs as a toddler in the late 1940s. I remember the snow, dog sled races, sunny summers & dark winters & seeing a small plane crash into a nearby mountain by the water. Now, it's one of the last places that I'd want to live. However, when young, it's easy to have a clear head.
 
Wow, nice to "meet" another ex-Alaskan! For what it's worth on a tuner-related note, Anchorage now has over 50 FM signals, it's amazing! Fairbanks has over 20. Fairbanks has a wonderful radio market, makes a receiver like mine really enjoyable with the good radio stations around here.
 
Aside nfrom reception, good programing is key. Too many Clear Channel top 40 stations. College stations, by & large, have good varied programing.
 
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