02 October 2007, 10:18 | #1 |
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rgb cable problem
I thought i would try connecting my amiga 1200 to the samsung lcd telly so bought an rgb cable..
picture is all terrible and wavy and i can see like a green bar rolling up and the words NO GROUND i think (it moves fast but i think thats what it says) .. i have tried two rgb cables now .. so i know its not a faulty one. anyone know what this issue is ? and how i can fix it ? cheers |
02 October 2007, 12:57 | #2 |
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@stuntpup
'elo looks like a right pickle... okay, before we take what the monitor is saying as truth, then it might be an idea to test it on another monitor (say tv). If you are still receiving crap signal, then perhaps your A1200 RGB port is not providing ground as it says. However if it works then its highly possible that the LCD wont sync to 15Khz RGB IN... have you attempted a composite scart connection? |
02 October 2007, 13:56 | #3 |
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hello all mighty zetr0
yeah composite is fine .. its what i was using before, but wasnt happy with picture quality. i will double check with another tv tomorrow. i had a playstation2 connected to the rgb socket on the samsung and that was fine.. but maybe it wasnt rgb .. i dunno .. thanks.. |
02 October 2007, 21:38 | #4 |
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@stuntpup
if in doubt take pictures (then post them) |
03 October 2007, 09:18 | #5 |
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A LOT of Amiga RGB SCART cables are wired wrong. They have the wrong voltages / signals on pins 8 and pins 16.
Pin 8 = 9.5v - 12v Pin 16 = 1v - 3v If the SCART on your LCDTV follows the rules to the letter and the voltages are wrong on your cables then you will either get a black screen or who knows what. Especially if it accepts S-Video and is set to S-Video in the menu system. You need to double check the wiring in your cables, check any settings in the LCD menu system. Last edited by alexh; 03 October 2007 at 09:23. |
04 October 2007, 11:23 | #6 |
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hi .. well i tried the amiga on another telly..
Goodmans crt widescreen with two scarts at the back. (one rgb one composite) rgb scart works ! the composite scart just shows a blank picture .. i can just about make the icons out so it is trying to show something .. so composite scart on the goodmans doesnt work. the samsung lcd again with two scarts (one rgb, one composite) from composite scart just a white picture.. from rgb i get a picture but with the wavy lines and moving green bar that says no ground. i would prefer to use it on the lcd telly.. do i have any other options to do this ? .. is it worth trying it through a scart block ? cheers |
04 October 2007, 12:01 | #7 | ||
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Quote:
Quote:
Last edited by alexh; 04 October 2007 at 12:08. |
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04 October 2007, 14:04 | #8 |
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rewire ?
is that as easy as it sounds ? !! |
04 October 2007, 17:55 | #9 |
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It depends on your skills. From your posts, I would say probably not.
Do you have access to a multi-meter, a soldering iron and a selection of resistors? First you need to check the wiring, open the SCART end of the cable and check what is connected to pins 16 & 8. Trace them back to the Amiga end of the cable and see which pins they are wired to. Once you have that information I can advise. If the Playstation RGB cable works in RGB... then the Amiga will work (eventually). |
04 October 2007, 19:38 | #10 |
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yeah thats pretty much beyond me im afraid ..
thanks for your input tho |
04 October 2007, 21:07 | #11 |
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@stuntput
if you want, i can lump together a schematic for you.... its quite simple, just like an overly large plug |
04 October 2007, 21:44 | #12 |
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@zetr0 .. ok i will give it a go .. if there is any soldering i could be in trouble .. haha
what miffs me is the fact i bought two cables advertised as amiga rgb/scart .. when in reality it should have been rgb/scart that only works on some televisions. in fact when i get a moment i will be putting my review of said cable on amigakit ! bah humbug haha |
04 October 2007, 22:03 | #13 |
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if you could take pictures m8, you must understand that both Alexh and I are *assuming* that your lead has the pins incorectly figged... and as you know... to assume makes an ASS out of U an ME..
insofar as soldering if there is any i would be supprised if there is more than two welds to do... |
05 October 2007, 01:44 | #14 |
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Not necessarily incorrectly wired, it could just be incorrect / no resistor values.
1-3v on Pin16 is impossible without resistors considering Amiga 23-pin D only has 5v. On older TV's 5v may work but if you are an LCDTV 100% following the spec, I dunno what would happen. If you bought your cable from AmigaKit... I would be inclined to think that they would have tried their best. Try an INTERLACED amiga screen, (workbench) see if that works. Last edited by alexh; 05 October 2007 at 01:49. |
05 October 2007, 09:59 | #15 |
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I have attached some pictures of each end of the cable i have
hopefully you can make everything out ok ! |
05 October 2007, 13:58 | #16 |
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@stuntpup
From the diagnosis, I have discovered that the Scart end is missing (pin 5) Blue Ground... You can source this from either the Shield[21] / Pink[9] or RED[13] It would seem that your Samsung is fussy about the All RED/GREEN/BLUE must be grounded.... interesting... i supose that IS spec... most wont have that problem as most grounds are tied to shield or all gounds are tied and then sourced from that (execept digital grounds btw).... strange... but kinda cool... in a strange way It might be wise to let AK know that some monitors are no longer tie-ing ALL thier grounds anyways two welds with a soldering iron and you should be up and running check out pic that should put you in the picture |
05 October 2007, 19:07 | #17 |
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ok .. lets see if i have this straight !
im desoldering one of the wires .. pink looks the closest so lets say that un. then splitting it so one goes to pin 5 and one back to pin 9 |
05 October 2007, 19:18 | #18 |
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yepo thats it
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05 October 2007, 19:26 | #19 |
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cheers for that .. will keep you posted !
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06 October 2007, 02:13 | #20 |
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I think a lot of Amiga RGB cables are like this, mine had problems last time I tried to use it with a modern TV. (as did one I butchered trying to fix!)
It was fine with the old 1084. I might take a look at the pins/wires and see if it's the same case with mine. |
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