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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: kiario on February 24, 2013, 02:35:45 PM
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Hello. I got hold of a A500 it is great except the picture with scart RGBb is rolling slowly upwards. Picture is superb otherwise. But not usable due to the scrolling. Is it a problem with the RGB out on the computer?
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Pal/NTSC issue perhaps? Using scart, I would assume you're in Europe/Pal area though. And NTSC on a PAL display usually involves losing the colors, but some devices might have trouble locking onto the vsync with a 10 hz difference. (My old 1702 monitor did the same thing with PAL outputs, but can be stabilized with vhold/vsize knobs, I'm in US (NTSC))
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And NTSC on a PAL display usually involves losing the colors
Not with RGB.
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i think kvasir has the right idea of whats going on..
and mongo is correct that there is no color loss on rgb out in NTSC or PAl . If you are losing colors, screen rolling. etc sounds like the monitor..
but I dont know squat about SCART as i dont live in Europa
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Hi thanks for the reply,
I am using a PAL amiga with RGB scart cable connected to a B&O TV. PC, game consoles work great both 50 and 60hz.
But with amiga the picture rolls. But not so fast that I cant see the 1.3 hand and disk when turnin on Amiga. The actual picture is great, its problem is that it is scrolling.
I read somehwere that pin 12 is the sync signal from amiga port, perhaps contact problem somewhere.
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check pin 19 on scart. it is very close to shielding and sometimes a short can occur. that would cause rolling.
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Thanks, will check pin 19. I have two scart cables and both produce the same result. But I will check.
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Hello,
I checked the cable and there is nothing connected to pin 19 and 20. So there is no sync? Strange, the cable is bought from a Amiga retailer. BR Anders
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sorry, my mistake, shielding is pin21, not 20.
but you should have csync on pin20 (opposite row).
pin19 is unconnected, but it still could cause problem if it gets shorted to GND/shielding.
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Thanks, well there is nothing connected to 19, 20 or 21.
I went ahead and ordered a cable from Amigakit. Hopefully it will work.
On RF mod I the problem does not exist, however quality is awful.
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Hi thanks for the reply,
I am using a PAL amiga with RGB scart cable connected to a B&O TV. PC, game consoles work great both 50 and 60hz.
But with amiga the picture rolls. But not so fast that I cant see the 1.3 hand and disk when turnin on Amiga. The actual picture is great, its problem is that it is scrolling.
I read somehwere that pin 12 is the sync signal from amiga port, perhaps contact problem somewhere.
Yeah, but did you try do adjust the vertical hold as suggested? Some TVs will work great with a console but the vertical hold might just be out of tolerance for another device.
Also, what's a "B&O TV"? Is that a brand name?
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B&O = Bang & Olufsen best CRT TV manufacturer there was.
There is no adjustment for vertical hold. I'll check the service setting but I doubt vertical hold is one of them.
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Bang&Olufsen, famous design product.
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Is it possible to switch between NTSC and PAL in the early startup menu and see if that remedies the problem?
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Hi,
I have the A500 Rev 6 board. Is it possible to softswitch without jumper?
For now I think my scart cable is not correctly wired.
The TV automatically switches between PAL/NTSC.
I also have a eee pc connected to the TV via scart/s-vhs and video box without issues.
Regarding PAL vs NTCS, I actually prefer the PAL image even though NTSC is less flickery. Actual image quality is more intense and colours are better in PAL.
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If your Amiga 500 has the Enhanced Chip Set, then you can get into the early startup menu to switch between PAL/NTSC by holding down both mouse buttons on power up.
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Some more info after much investigation. My conclusion is that the scart splitter I use is causing the issue. If I connect the Amiga through the splitter(quality splitter sold on amikit) the screen rolls for the first 15 minutes or so then gradually stabilizes. If I connect the amiga directly to scart on TV it syncs immediately. So the splitter is probably "eating up" the signal in some way.
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Some more info after much investigation. My conclusion is that the scart splitter I use is causing the issue. If I connect the Amiga through the splitter(quality splitter sold on amikit) the screen rolls for the first 15 minutes or so then gradually stabilizes. If I connect the amiga directly to scart on TV it syncs immediately. So the splitter is probably "eating up" the signal in some way.
The fact it stabilizes after time leads me to believe that switcher / splitter has a dodgy Capacitor in it. Would be interesing to see the inside of that splitter. It could still be the amiga thats 'warming up' with a similar cap related problem, which becomes noticeable when the signal passes through that splitter.
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I am sure it is not a fault with the splitter since I have a dreamcast, SNES and megadrive connected through it without problem. Sync issue only with Amiga connected to the splitter.
There could perhaps be some kind of compatibility issue with the splitter and amiga. Maybe the signals from the amiga are very weak and absorbed by the splitter. Or the splitter is not wired to function 100% with amiga.