CED VideoDisc and Player Discussion

[ramsejp]

I just picked up a SJT 400 at an estate sale today. It seems to be functioning fine except there is no sound. The video is working fine. I have it setup using RCA cables and I don't have a TV that accepts coax, so I'm unable to test that connection.

Thoughts on next steps?

I also got a SJT 300 from the same sale. When I turn it on it just makes a noise and won't let me load a disc. Bad drive belt?

Thanks!

[SelectaVision420]

hi there, do you mean sjt 400? it might have a bad solder joint somewhere in the audio board, im not sure if the stylus could be the culprit in this situation, as far as the 300 its most likely a belt issue
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(2)Sears 274 & 934(80150,10&11350), sft100, sgt250, sjt 090-400, vp550, VDR3000, VP2000 & 4000
complete '84 Dimensia Owner

[ramsejp]

Shoot, yes, SJT 400. Thanks.

Thanks SV420. Hmm, anyone else familiar with this issue that may be able to point me where to go or instruct me on how to fix this problem?

[SelectaVision420]

you have to check the solder connections at the rca jacks, i heard that is a typical spot to check
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(2)Sears 274 & 934(80150,10&11350), sft100, sgt250, sjt 090-400, vp550, VDR3000, VP2000 & 4000
complete '84 Dimensia Owner

[cbertra2]

You probably have a bad IC sound chip. Check with CEDatum they helped me once with this same issue.

[ramsejp]

I was finally able to test the coaxial connection and no sound there either. Bummer. I got the 300 to work after changing the belt, so at least I have a player. The picture isn't as good as I remembered. Not sure if dirty discs, old stylus, or just the way they are.

Guess I will check with CEDatum.

[SelectaVision420]

[Jesse Skeen]

Only other thing I can think of is that the 400s do have a play mode with no sound, meant for some of the interactive discs. If you have the remote, try hitting the regular Play button on it and see if that helps.
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Videodisc and stereo sound- there's no better value around!

[blindfury420]

I normally try not to say or add anything when people say the right thing or guide you in the correct way. It is pointless to add my two cents or even post that I agree with what is being said but I have to explain the no audio a lil better..

I have only ever had one player with no audio be just the rca plugs connection to the board. A stereo player with no sound can be one of three things almost every time. All three are bad IC's.

1. Bad U4101 (L+R) Audio FM Demod IC
2. Bad U4102 (L-R) Audio FM Demod IC
3. Bad U4200 Track/Hold and Mute Audio (C Mos Switch) IC

You need a service manual and a multimeter to test the voltages.

A manual way to test if its all or just one of the IC's it to test a mono ced, then a stereo ced, then a dual audio track ced.


If it doesn't play a stereo disc it could be one to all three IC's.
If it plays a mono its one IC and likely the L+R U4101
If it plays nothing, meaning dual audio, stereo, and mono it is likely the U4200

It can be a combo of all three or any two together or one. The only real way to know is to test voltages and replace if needed. It could be other things but no audio is 99% one of those 3 or all 3 IC"S have gone bad

If this is something you want to try I can send you a picture of the voltages on each IC.
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I dont own

McMicheal 5001h
Hitachi VIP202P
JCP 686-5705
RCA SKT265, SKT300
RCA SJT400X, SJT425

[ramsejp]

Thanks for the reply. Is there an electronic or scanned copy of a service manual somewhere that I can access? I have a multimeter, and as long as I know what to check and what it should be, I can test it.

Thanks.

[blindfury420]

I forgot to add that it could also be U4600.

A static charge applied to L and/or R audio connectors on the back of the panel can knock out the U4600.

Also the L+R and L-R IC will need to be adjusted with a frequency counter after you install it!

I can still post pics of the voltages if you want!
_________________
I dont own

McMicheal 5001h
Hitachi VIP202P
JCP 686-5705
RCA SKT265, SKT300
RCA SJT400X, SJT425

[happycube]

http://www.dragons-lair-project.com/tech/pages/nfl.asp has the SJT400 service manual (the only free pdf CED manual I can find...)

And no ESD protection on the RCA jacks? Blah.

[ramsejp]

[blindfury420]

Test voltages in load mode, iirc any difference high or low over 3% is bad. I will check for you later.
_________________
I dont own

McMicheal 5001h
Hitachi VIP202P
JCP 686-5705
RCA SKT265, SKT300
RCA SJT400X, SJT425

[SelectaVision420]

[blindfury420]