Help reqd for a S-video to RCA cable for T21

[hit_ny]

I have a T-21 and would like to connect it to TV. The TV only has a BNC connection for video. I use a BNC-RCA adapter on it.

I managed to find a s-video-RCA (with 3 cinch connectors) cable. Tried it and i got a black & white image (using the yellow RCA). Played with PAL & NTSC settings etc was no use. Retuned it to the shop and got a S-video to RCA with 1 cinch connector, this time i got a garbled image on the screen. Sigh..Figured i'd be better off with a custom made cable.

Now the T21 uses a 7-pin S-video connection, this tells me from searching the net that there is a composite video signal being output that might solve my color problem

http://www.weethet.nl/images/pc2tv/s-vi ... _7pins.jpg shows a plug with 7 pins.

S-video Function

1 . . . . Luma ground
2 . . . . Chroma ground
3 . . . . Luma
4 . . . . Chroma
5 . . . . (blanking ??)
6 . . . . Composite video
7 . . . . Composite ground

I have been trying to find a pinout of the s-video out of the T21 without any luck. I'm not sure if pin 6 is really composite video or pin 5 ? since its propietary.

Would connecting composite video & gnd to the rca cable and ignoring the first 4 pins do the trick ?

Composite ground >-------- RCA Composite Ground

Composite video >-------- RCA Composite Video

Edited by Moderator: No images in this forum, links only.

[GomJabbar]

Maybe this link will help.

http://forum.thinkpads.com/viewtopic.php?t=14218

[MadeInJapan]

They sell the 4 point S-Video to RCA cable on eBay. Forget the 7 points...I've looked and can't find them. I just use a mini-jack to RCA cables for the audio and it works fine on my T30 as well as those with T22's at work. I assume your TP will be the same. These are cheap and work fine. Here's one like the ones I've bought: http://cgi.ebay.com/NEW-3-S-VIDEO-to-RC ... dZViewItem

[hit_ny]

Thanks for the replies
Gom Jabbar - i looked at those threads earlier but they talk about SCART, i dont need one. My TV has a BNC which i have already attached a RCA adapter to. I'm pretty convinced this is a cable problem, video drivers etc are the latest availible from IBM's site. The TV can handle multiple systems as well so PAl/NTSC is not an issue.

They sell the 4 point S-Video to RCA cable on eBay. Forget the 7 points...I've looked and can't find them. I just use a mini-jack to RCA cables for the audio and it works fine on my T30 as well as those with T22's at work. I assume your TP will be the same. These are cheap and work fine. Here's one like the ones I've bought: http://cgi.ebay.com/NEW-3-S-VIDEO-to-RC ... dZViewItem

I tried a similar cable to the one mentioned there and it did not work. It's not possible for me to order the one you mention from ebay. But if i know what the pinout is i can get one built. The cable you have is combining the s-video to composite using something similar to http://pinouts.ru/data/svideo2RCA_pinout.shtml

I thought i could simplify things since the T21 already puts out composite, which pin that is (5,6, other) etc is what i want to know ? There's at least 6 possible combinations here hehe.

[Nolonemo]

I'm jumping in here, though I'm ignorant

By BNC connector, do you mean the connector that your coax from a VCR or TV antenna would plug into? If that's the case, I think trhe problem is that you're trying to feed the TV the wrong kind of signal, i.e. a video signal rather than a broadcast signal.

Try this experiment. Get hold of a VCR, put in a tape and play it on the TV using the coax connection. Now try playing the tape using the RCA out of the the VCR and your RCA to BNC adaptor. I'll bet it doesn't work.

I think what you need is an RF adaptor like those used to connect gaming systems' RCA outs up to old TVs with only an antenna adaptor.

http://www.radioshack.com/product.asp?c ... id=15-2526

Of course, if this is what you're aready using, this post was a waste of time....

[DIGITALgimpus]

The problem with s-video is it's video only (no audio), so you need 2 cables.

Get a s-video cable of a length you desire (you can find them virtually anywhere), and use this adapter to convert the end to a video cable. This gives you 1 of 3 prongs for RCA. The yellow video cable.

Then one of these converts your audio (from your headphone port) to RCA audio. THis has the cable/adapter inside, so only 1 part.

[hit_ny]

I'm jumping in here, though I'm ignorant

By BNC connector, do you mean the connector that your coax from a VCR or TV antenna would plug into?

Yes

If that's the case, I think trhe problem is that you're trying to feed the TV the wrong kind of signal, i.e. a video signal rather than a broadcast signal.

Try this experiment. Get hold of a VCR, put in a tape and play it on the TV using the coax connection. Now try playing the tape using the RCA out of the the VCR and your RCA to BNC adaptor. I'll bet it doesn't work.

It does work, that's how the VCR plugs into the TV One cinch connector goes to the BNC-RCA adapter thats on the BNC. The other cinch connector goes to one of the audio ins. Mono sound tho, not too bothered by that.

I think what you need is an RF adaptor like those used to connect gaming systems' RCA outs up to old TVs with only an antenna adaptor.

http://www.radioshack.com/product.asp?c ... id=15-2526

Of course, if this is what you're aready using, this post was a waste of time....

Otherwise known as a RF modulator. If i were going from VGA to to BNC then yes, but the T21 has a S-video out.

Another reason i'm confident that this is not the case is i suceeded to get a b/w image of my desktop on the TV using the yellow cinch of the S-video to 3RCA cable.

The quest now is to get a colour image. I am assuming the video composite signal on pins (5 or 6) puts out a colour signal. I was looking for clarification as to which pin it was.

Once i know that i can get a cable built for < $5 that will do the job

..and use this adapter to convert the end to a video cable.

It looks like this adapter plugs into the s-video out of the thinkpad and then all i need is a RCA cable to attach between it and the TV.

So you have this adapter working with your thinkpad ? also does your thinkpad have a 4-pin or 7-pin s-video out ?

Then one of these converts your audio (from your headphone port) to RCA audio. THis has the cable/adapter inside, so only 1 part.

Got that already thanks.

[DIGITALgimpus]

that adapter can go directly in to most TV's. You use the svideo cable to get the distance you need. AFAIK it works with 4 and 7 pin, though check with your local radio shack.

[MadeInJapan]

I have used a friend's radio shack adapter and it works fine. For me, I didn't want to pay over $20 for something that should cost under $5, IMHO.

[hit_ny]

I have used a friend's radio shack adapter and it works fine. For me, I didn't want to pay over $20 for something that should cost under $5, IMHO.

Agreed, Can you confirm whether the adapter you used had 4 or 7 pins going into the S-video port ?

I'm beginning to lean towards building a 4 pin instead since thats more standard. Means i could re-use the cable with other laptops. It's quite maddening cos each manufacturer seems to number pins 5, 6 & 7 differently. The first 4 pins however tend to be in the same place. Which is is what these cable makers are exploiting and selling for a hefty profit.

The 4-pin is combining the two s-video signals (which i think might be better (?) than just taking the composite signal out of 5,6, or 7) as described below.

http://www.tkk.fi/Misc/Electronics/circ ... video.html

[GomJabbar]

The same Radio Shack adapter, I have also. It is a 4-pin. However my T42 also has a 4-pin S-Video Jack. So both are 4-pin.

FWIW it uses pins in locations 1,2,3,& 4 from your diagram.

[Nolonemo]

From http://www.audioholics.com/techtips/aud ... rtypes.php :

2. The BNC Plug and Jack:
The BNC is the standard connector for most video signals on professional gear, and is showing up increasingly on high-end consumer gear as well. It will be labeled similarly to the RCA, indicating composite video (one connection), Y/C s-video (two connections), Y/Pb/Pr (three connections), or one form or another of RGB. The most common confusion with BNCs, in our experience, is that people often assume the female connector is a male; the problem is that both the male and female connectors have what looks like a pin in the center. On closer inspection, however, you'll see that a female BNC's "pin" is actually a receptacle for the male pin. A panel-mounted BNC will ALWAYS be female; a cable-mounted BNC will almost always be male, though there are exceptions (such as our breakout adapters, which have female BNCs to join with standard cable-mount male BNCs).

3. F-Connectors:
The F-connector is the screw-on type connection used for most antenna and cable TV connections. F-connectors are rarely used for anything other than RF; the one notable exception being that they were used as digital audio connectors on some laser disk players.

I assumed the OP was calling an F-connector on the TV a BNC connector. If it's a BNC connector, then it should take a video signal and the RF converter isn't needed. If it's an F connector, then the OP would need the RF converter as I posted.

Sorry if I muddied the waters.

[Nolonemo]

BTW, for those looking for a reasonably priced S-Video to RCA converter, here's one that's 1/4 the cost of the one Radio Shack sells, and it's bidirectional.

I've bought from them and can recommend the place for low cost good quality audio and video connectors.

http://www.partsexpress.com/pe/showdetl ... er=180-140

And for those who want to build their own, here's a schematic. Note the need for a capacitor in the circuit.

http://www.epanorama.net/circuits/svideo2cvideo.html

BTW, the schematic article mentions the 7-pin versions:

What if my PC graphics card has a 7-pin S-video connector instead of 4-pin ?
The four pin S-video connector as shown above is the standard connector for carrying S-video. Those seven pin connectors seen on some PC graphics cards are non-standard connectors for carrying S-video. The use of the pins on those seven pin connectors is not standardized and can vary from manufacturer to manufacturer. (For some strange reasons some manufacturers in PC industry just keep constanly breaking the industry standars and create lots of confuzion to users when doing so).

Generally the four pins on those 7-pin connectors on the same places as the standard four pin S-video connector have practcly always the same fuctionality as those pins in S-video connector. The other three pins can have then some extra signals which are not part of S-video (usually some pins of those carry composite video and some control signals, but the use of those three extra pins vary quite much). So if you encounter 7 pin connector for S-video, then forget the three center pins... just use the four on the standard positions. The circuit shoudl work with those connectors as well.

[hit_ny]

Thanx Nolo for your suggestion, i got this one

http://www.partsexpress.com/pe/showdetl ... er=180-141

Colour works perfectly.

Fancy meeting a MC user in here