CED VideoDisc and Player Discussion

[RockSolid87]

I've had my SJT-300 for a number of years now and have a handful of mono and stereo discs. The player has functioned as it should until recently. Even though it's been hooked up to our TV, I haven't used it since we moved a couple of years ago. Here's the problem:

The player is hooked up via RCA outputs going directly into our TV (50" LG 4K). The audio on stereo discs comes through just fine, but the audio on mono discs is mostly static - sounding like the TV is tuned to a channel with nothing on it. You can hear a little of the movie in the background, but mostly static. I noticed when hooked up via coax not only does the audio come through perfectly on both stereo and mono discs, but the picture quality is also improved. Using the RCA jacks is also yielding a picture quality as if I were using a low quality poorly shielded video cable, which I'm not. I should also note that the stylus and discs are in good shape. I tried every disc I have with the same results each time.

Where would I begin to diagnose and fix this problem? Any insight and/or advice would be greatly appreciated!
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[jsdspif]

I think I would start by getting the service manual for it. I think they're on the site somewhere,if not just internet search for it and it's free. Then look in the manual to see how to open it up(if you don't know already) and get the cartridge out and send it to CEDatum to have it cleaned and inspected. While that's happening go over the service manual real well. The addendum at the end of the service manual has troubleshooting charts. The unit has 2 fm demodulator IC's and the manual has what the voltages should be at the various pins, that is how I diagnosed my audio IC's were bad.
the video issue sometimes the solder joints for the rca jacks start to crack and cause problems.
I see at the end you say stylus is good but unless you just had it cleaned/inspected I'd send it in,it's free to have it cleaned inspected,or at least you take a look at it under pretty strong magnification. They can cause such a wide range of problems if there is a problem with it and even if you've studied the service manual before, go ahead and study it again. I'm thinking if you have studied it before it may have been years ago.

[RockSolid87]

I bought the stylus new from CEDAtum when I first got the player. That's been about 10yrs ago, but it's seen very low use and has never been removed. If the stylus were dirty or problematic, wouldn't it be safe to say it would cause issues regardless of what discs were played and what output I use? Coax works perfectly fine for mono and stereo discs and gives a perfect picture.

Wouldn't the IC's be affecting coax audio as well?

I have the service manual, but haven't really what you would say studied it. I'm no good with schematics. I also know how to open the unit, so I'll recheck the solder joints and see if I can locate the IC's and try to check those too.
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Jesus Christ is the ONLY way to Heaven! (Acts 4:12)

[jsdspif]

there's one of the ic's for the initialgathering of the audio and then there's a stereo section with another one of those same type of IC that section is what goes to the rca jacks I thinkI can't really rememebr exactly what goes on but there are 2 fm demodulator ic's and I've had them both go bad on sgt players which are basically electronic wise very close to being the same. If not the sameWith the stylus it may be possible it picked up some kind of debris from a disc or damage or something, basically as long as you have it apart send it in ,get a report on it and it just costs you maybe 7 or 8 dollars or something in postage.
The rca jacks I had problems with intermittent audio/no audio finally someone here said check the solder connections and sure enough all of them were somewhat cracked/cold solder joint touched them all up and that's the player I use,

[RockSolid87]

Thanks for the information! I'll try to get all of that checked this weekend. I have the original "dead" stylus as well, so if the IC's check out OK I'll just send the one in for checking/cleaning and the other for rebuilding.
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[jsdspif]

I think you may need a good cartridge in the player to perform/validate the voltage readings, but you could give it a try without a cartridge and if all the readings are correct then I guess you don't need one in it. I don't remember but working on mine it seems like something gave me trouble and I think I needed a cartridge in it.

[RockSolid87]

I'm not sending off the cartridge until I check the IC's first. I don't expect the cartridge to be the issue.
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[kitchensynch]

If you can watch stereo titles just fine then it's not your cartridge. Stereo sound on CEDs is multiplexed much like FM stereo and your problem is not related to the cartridge.

Perhaps you have the TV sound set incorrectly so that mono is incorrectly phased...do you use surround sound? Change the setting or turn it off and report back.
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