C128 RGBI to S-Video cable problem?
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From: JohnH. on 2 Oct 2006 20:39 I have purchased a video cable for my C128 that is basically two cables in one. It has a jack that plugs into the C128 video port with a corresponding end that connects to a composite input on a monitor. The cable also has a jack that plugs into the C128 RGBI port with a corresponding end that connects to an S-Video port. It's the RGBI to S-Video that is the problem. It does not work. I have tried it with literally seven C128s. * I've tested the S-Video input on the monitor with other input sources and it works. * I've connected C128 RGBI port to a Commodore monitor and it worked. * I have returned the cable to the vendor and got another cable. I have gotten the same results with the second cable. This is a very reliable vendor that I have purchased several cables from. He does really hi-quality work. I feel like I'm missing something here. I took the cover off of the RGBI connector. There are only two wires connecting to pins 1 and 7 respectively. 1 = Ground 7 = Monochrome (per C128 Programmer's Reference Guide, p388) Theoretically, are pins 1 and 7 all that is necessary?
From: a7yvm109gf5d1 on 2 Oct 2006 21:38 JohnH. wrote: > I have purchased a video cable for my C128 that is basically two cables > in one. It has a jack that plugs into the C128 video port with a > corresponding end that connects to a composite input on a monitor. The > cable also has a jack that plugs into the C128 RGBI port with a > corresponding end that connects to an S-Video port. > > It's the RGBI to S-Video that is the problem. It does not work. I > have tried it with literally seven C128s. > > * I've tested the S-Video input on the monitor with other input > sources and it works. > * I've connected C128 RGBI port to a Commodore monitor and it worked. > * I have returned the cable to the vendor and got another cable. I > have gotten the same results with the second cable. > > This is a very reliable vendor that I have purchased several cables > from. He does really hi-quality work. I feel like I'm missing > something here. I took the cover off of the RGBI connector. There are > only two wires connecting to pins 1 and 7 respectively. > > 1 = Ground > 7 = Monochrome (per C128 Programmer's Reference Guide, p388) > > Theoretically, are pins 1 and 7 all that is necessary? Are you 100% sure that the cable was described as a RGBI to S-Video cable? I've never heard of a such a thing. At best, all you'll get is the mono video signal that's made for you inside the guts of the 128 presented to you on a RCA jack. It takes a hell of a lot more than a few wires to translate RGBI to S-Video. And you'll never get the sharpness of a true RGBI connection because of bandwidth limitations. Would a RGBI to VGA converter be of any help? As luck would have it, I'm working on one. OK, it's taking a while but it's getting done.
From: JohnH. on 2 Oct 2006 21:59 Here is a link to a page that describes the cable. http://www.vintagecomputercables.com/guides/connection%20guide%20commodore%20128%2040%2080%20column.pdf It does say at the bottom, "Note 2: The 80-column s-video signal is monochromatic." But, I would think I should be getting at least something on the S-Video given the description of the cable. Am I missing something here? Thanks, John
From: a7yvm109gf5d1 on 2 Oct 2006 22:14 JohnH. wrote: > Here is a link to a page that describes the cable. > > http://www.vintagecomputercables.com/guides/connection%20guide%20commodore%20128%2040%2080%20column.pdf > > It does say at the bottom, "Note 2: The 80-column s-video signal is > monochromatic." But, I would think I should be getting at least > something on the S-Video given the description of the cable. Am I > missing something here? > > Thanks, > John Never seen this cable before, but it looks like it takes s-video from the C64 side and b/w video from the 128's side. OK, that explains the s-video part, it's for the VIC side. It will not display RGBI as s-video. I'd say you need to make sure you're connected to a video input and not a RF input, and tell your display device to use the composite video input. Some TVs have a bunch of different inputs and you need to select the right input to see the signal. It looks like you need to plug the cable's red connector to the monitor's yellow jack. Also check that the 128 is told to boot up in 80 column mode by pressing the 40/80 switch on the keyboard (down= 80 cols). Otherwise the machine boots up with the VIC chip and displays nothing on the 80 column display. What monitor/TV/projector/IMAX screen are you connecting to?
From: Sam Gillett on 2 Oct 2006 22:42
<a7yvm109gf5d1(a)netzero.com> wrote ... > > Also check that the 128 is told to boot up in 80 column mode by > pressing the 40/80 switch on the keyboard (down= 80 cols). Otherwise > the machine boots up with the VIC chip and displays nothing on the 80 > column display. The Escape-X sequence can also be used to toggle between 40/80 column mode without powering down or using the reset button. Just press and release the "ESC" key, then press and release the "x" key. -- Best regards, Sam Gillett Change is inevitable, except from vending machines! |