1986 Sears LXI 20" with Nudes

[CRTs4life]

@Wiscojim I had no idea about the "Sams" site with all the scans. Thank you for that.
@collectorad Thanks for that page from Taxan.

I'm figuring over the holidays I will tinker with it. First I am going to confirm those 2 grounds from the Taxan reference. I believe the only thing I have that outputs rgb natively is a model 1 Sega Genesis. Easy enough to make a jumper harness for testing.

Even if it's not rgb I still think it's neat. In 1986 with modest means we had Zenith's that we loved, even the neighbor that had a Trinitron (and let us know they did) didn't have stereo like this Lxi.

[WISCOJIM]

Originally Posted by CRTs4life

@Wiscojim I had no idea about the "Sams" site with all the scans. Thank you for that.

The Sams site isn't cheap, usually around $22 per service folder.

If you post a free classified ad here on VK and/or on ARF, you may find one of us with a spare Sams Photofact folder to sell cheap or even free.

http://www.videokarma.org/forumdisplay.php?f=60

http://antiqueradios.com/forums/view...47327ef7928bc7

.

[user181]

Here's a link to the Photofact:

https://www.samswebsite.com/en/photo...ndex/id/161680

It's $22.00 for a PDF download, or a couple bucks more if you want to buy a hard copy. Not cheap-cheap, but it's hardly an arm-and-a-leg, either. Especially if you don't get any other leads on it.

I've bought a couple Photofacts from them over the years and can vouch that it's legitimate and works as advertised. They were responsive to me when I had an issue with readability in one place, and they ended up rescanning the whole thing at much better resolution for me.

[Jon A.]

Originally Posted by Electronic M

The EIAJ connector has a completely different pinout/signal set on that TV than the one on your Umatic does. The Umatic has 4 signal lines in it: (composite)Video in (Composite) Video out, Audio in, Audio out....That Monitor has a different 4 lines: Red video, Blue video, Green video, Sync...If you were to plug your umatic into that set it would not work.

My U-Matic has the identical EIAJ connector with "monitor" stamped above it.

[Electronic M]

Originally Posted by Jon A.

My U-Matic has the identical EIAJ connector with "monitor" stamped above it.

So does my U-Matic...My point is just because it has the same connector don't mean it uses the same signals.

If you plug the white RCA jack from your DVD player into your TV's Yellow RCA jack it will be the same as connecting your umatic to that set.

[jsowers]

This connector is very specific and unique and the signal is meant to go back and forth to and from a VTR or a Umatic deck. I think it really only had one purpose. The cable used has the same large multi-pin EIAJ male connector on both ends and it enables the VTR or Umatic to record TV programs from the TV's tuner and it lets the VTR or Umatic play tapes on the TV. A two-way audio-video cable. It's as simple as that. I've used these EIAJ cables many times and they work flawlessly when the cable is good. It also locks in with a nice snap and doesn't come loose easily.

It's possible there were pro models of VHS or Beta VCRs with that same connector on them in the early days. EIAJ connectors were mostly used in pro setups or AV use in schools and rarely in a home situation and not, that I know of, on a computer.

By 1986 that was pretty old technology, but I've seen many 13" Panasonic monitors from the 1980s with the same EIAJ connector and these pre-date most home computers and were meant to simplify early video recording. A one-connector solution instead of using four RCA cables. And you could use the monitor's tuner and antenna instead of needing one in the recorder. This was also before widespread use of cable TV.

RCA jacks are really no comparison to this connector since they can carry many different kinds of signals. I even have an RCA jack in a Zenith radio-phono that carries 6 VAC to the little dial lamp jewel on the base of the console. This large greenish EIAJ connector is only meant to connect TV monitors to video recorders. Anyone who cut their teeth using those old video machines will say the same thing.

[Electronic M]

Originally Posted by jsowers

This connector is very specific and unique and the signal is meant to go back and forth to and from a VTR or a Umatic deck. I think it really only had one purpose. The cable used has the same large multi-pin EIAJ male connector on both ends and it enables the VTR or Umatic to record TV programs from the TV's tuner and it lets the VTR or Umatic play tapes on the TV. A two-way audio-video cable. It's as simple as that. I've used these EIAJ cables many times and they work flawlessly when the cable is good. It also locks in with a nice snap and doesn't come loose easily.

It's possible there were pro models of VHS or Beta VCRs with that same connector on them in the early days. EIAJ connectors were mostly used in pro setups or AV use in schools and rarely in a home situation and not, that I know of, on a computer.

By 1986 that was pretty old technology, but I've seen many 13" Panasonic monitors from the 1980s with the same EIAJ connector and these pre-date most home computers and were meant to simplify early video recording. A one-connector solution instead of using four RCA cables. And you could use the monitor's tuner and antenna instead of needing one in the recorder. This was also before widespread use of cable TV.

RCA jacks are really no comparison to this connector since they can carry many different kinds of signals. I even have an RCA jack in a Zenith radio-phono that carries 6 VAC to the little dial lamp jewel on the base of the console. This large greenish EIAJ connector is only meant to connect TV monitors to video recorders. Anyone who cut their teeth using those old video machines will say the same thing.

There were at least two signal/pinout variants of this connector:
1.) RGB single directional video (no sound) as used on the op's monitor see this link http://www.minuszerodegrees.net/manu...%20Pinouts.jpg
and 2.) bidirectional audio and composite video like you are thinking of see this link http://www.labguysworld.com/Connectors.htm and scroll about half way down to the section with the text: "Old EIAJ VTR decks and monitors had this convenient connector. It saved the operator from having to connect four separate cable in order to record off air programs. The jumper cable contains four high quality coax cables within it. This cable was wired one to one, straight through as shown above. On the monitor end, simply reverse the in/out nomenclatures."

I'm now done trying to explain the difference....I've stopped caring if anyone gets it.

[CRTs4life]

I have a brief update. Pins 5 & 6 do have continuity to ground (just like the Taxan reference guide from @collectorad's help). I couldn't fight temptation anymore this evening. Good indicator it might actually be analog rgb.

I either need to make or find male pins for the connector side, or take the video board loose from the housing and go after them that way in order to test the Sega. Not entirely sure how yet but I will soon though. Have to sleep on it for now.

Thanks for all the replies. Everyone. I definitely wasn't intending to get people riled up with each other either over that damn connector.

[Jon A.]

Originally Posted by Electronic M

There were at least two signal/pinout variants of this connector:
1.) RGB single directional video (no sound) as used on the op's monitor see this link http://www.minuszerodegrees.net/manu...%20Pinouts.jpg
and 2.) bidirectional audio and composite video like you are thinking of see this link http://www.labguysworld.com/Connectors.htm and scroll about half way down to the section with the text: "Old EIAJ VTR decks and monitors had this convenient connector. It saved the operator from having to connect four separate cable in order to record off air programs. The jumper cable contains four high quality coax cables within it. This cable was wired one to one, straight through as shown above. On the monitor end, simply reverse the in/out nomenclatures."

I'm now done trying to explain the difference....I've stopped caring if anyone gets it.

Oh I got it before this, I'm brighter than some give me credit for. Seems the RGB variant is all but useless though, I don't know of a single device with that kind of video output. I'm sure you could name a few though.

[colectorad]

Originally Posted by CRTs4life

I either need to make or find male pins for the connector side, or take the video board loose from the housing and go after them that way in order to test the Sega. Not entirely sure how yet but I will soon though. Have to sleep on it for now.

Make sure to add a 220 uF capacitor in series with a 75 Ω resistor for R, G, B, and c-sync. They are required, but not included in the Genesis due to cost cutting measures.

[CRTs4life]

Thanks! Colectorad
(I am not an engineer so please bear with me)
About the polarity of the capacitors, considering electron theory, negative towards the TV?
And the resistor goes after the cap?
No schematic so I have to ask in order to not tear anything up.
This sounds a lot like the rgb mod of older tvs that is growing in popularity.

Thanks again to VK and its legions.

[Jon A.]

I'm not familiar with the electron theory but negative on the electrolytic capacitors goes to ground; hooked up the other way they go poof.

Chances are you'll eventually tear up something, or at least do a sloppy job and want to re-do it eventually, I did quite a bit in the early stages of the learning process. By the way I always use 105 degree Nichicon capacitors. Avoid oddly-branded Chinese caps at all cost.

[CRTs4life]

I'm not tearing anything up if I can at all help it.
The reference to electron theory vs conventional theory is about the direction electrons flow. + to - or - to +. Convincing arguements both ways.
Anyway,...not that relevant I guess.
I'm familiar with Nichicon, Rubycon, etc. I am a career master auto tech and I never use cheap parts if there is any way at all possible not to.
I bought several of the pre-made cap kits for my old videogame consoles and recently I discovered a depot place in Fla. that sells caps (not cheap ones) in bulk. So I am good to go in that dept. after buying a huge assortment priced right.

P.S.- I will post pix of the Sega running when I get this figured out.

[Jon A.]

Originally Posted by CRTs4life

I'm familiar with Nichicon, Rubycon, etc. I am a career master auto tech and I never use cheap parts if there is any way at all possible not to.

Ah, an excellent head start there. I hadn't done a whole lot with a soldering iron before starting in TVs. I too avoid any cheap parts like the plague.

[colectorad]

Originally Posted by CRTs4life

About the polarity of the capacitors, considering electron theory, negative towards the TV?

Yes.

Originally Posted by CRTs4life

And the resistor goes after the cap?

It's not critical, but most manufacturers do it that way.

Originally Posted by CRTs4life

This sounds a lot like the rgb mod of older tvs that is growing in popularity.

You mean this?