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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Super TWiT on June 04, 2010, 07:57:06 PM
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I just got my a520 in the mail today (been using monochrome off of a500) and it seems to be acting a little weird. The picture will be in black and white and jump around and then suddenly clear up by the time the workbench screen loads. Once it loads I get a perfect color picture. I took the workbench disk out so it will display the hand with floppy upon boot. Here again the picture is all jumpy and in black in white. Any ideas? I have a kickstart 1.3 a500 with a 1 mb agnus chip and a 512 k expansion in the trapdoor. Everything else is standard. The a520 adaptor came from new york, so I assume it is NTSC. The workbench copy I got is from the amiga forever series (I burned it onto a floppy) so maybe the disk is pal?
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I just got my a520 in the mail today (been using monochrome off of a500) and it seems to be acting a little weird. The picture will be in black and white and jump around and then suddenly clear up by the time the workbench screen loads. Once it loads I get a perfect color picture. I took the workbench disk out so it will display the hand with floppy upon boot. Here again the picture is all jumpy and in black in white. Any ideas? I have a kickstart 1.3 a500 with a 1 mb agnus chip and a 512 k expansion in the trapdoor. Everything else is standard. The a520 adaptor came from new york, so I assume it is NTSC. The workbench copy I got is from the amiga forever series (I burned it onto a floppy) so maybe the disk is pal?
I assume you live in a PAL region with a PAL TV?
I have no experiance with NTCS Amigas what so ever, since I have only bought PAL region amigas.
tho I have imported alot of Sega consoles etc and without my converter I allways get a B/W output.
So i guess it has to do with that.
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Sounds like you have a pal A520, the black and white display is a typical effect.
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Yepp, depending on where you live I can send you a PAL A520 for free if you pay postage :)
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On a side note: Since Workbench 1.3 the OS is PAL/NTSC "agnostic", there no such a thing like "PAL 1.3" or "NTSC 2.1".
Just the Amiga itself is tied (or not) to a region colour encoding.
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I meant to mention that I am in an ntsc region not pal. I noticed sysinfo has said in the past that I'm pal, but even when I run sysinfo in my emulator changing between pal and ntsc settings it still says I run pal. The only thing that remains the same between the sysinfo readings is the wb image. It does sound like its the wrong video format, but if that was the case why would it clear up?
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Well if your machine is NTSC and you A520 is NTSC then it is a hardware fault of some kind.
Try leaving the machine on with the Workbench requester screen for a couple of minutes to rule out intermittent/warm up failure being a coincidence.
What happens when you boot a game disk instead of Workbench?
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I believe they are both ntsc (how do I check?). If I let the disk request screen wait it still jumps around, and finally there is no picture at all. When I use a game disk it works. As soon as it loads the screen is crystal clear.
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I noticed that for maybe half a second when I first start my amiga the screen is red then quickly disapears. Is this a sign that the kickstart is loose?
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Is the quick red screen a new clue?
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Is it possible that your 500 defaults to PAL (hardware default, a 1 Meg Agnus is switchable) and is then switch to NTSC by a Prefs setting? Unfortunately 1.3 lacks the early startup screen where you could easily switch the hardware.
BTW: A520s are either PAL or NTSC. There's no way to get any colors on an NTSC monitor/TV with a PAL A520 - that rules out any mismatching here.
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Well, maybe, but the monochrome output works just fine (no jumping picture). I have a one meg agnus so maybe I could switch it? You don't think its a kickstart issue then?
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Well, maybe, but the monochrome output works just fine (no jumping picture). I have a one meg agnus so maybe I could switch it? You don't think its a kickstart issue then?
Strange issue. If it was me I would start by re-seating all the chips including kickstart.
But I don't know how likely it's the kickstart either (or any pal issue) since everything works fine from the monochrome. I would suspect something with the RGB port or A520. But since the RGB port with A520 works fine when loaded I'm at a loss as to what that could be either.
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The only thing that got me thinking kickstart is that I noticed that for like half a second the screen turns red when I first turn the amiga on.
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The only thing that got me thinking kickstart is that I noticed that for like half a second the screen turns red when I first turn the amiga on.
Yeah, I think red is for rom issue on startup. So worth re-seating and checking. Maybe the rom issue is having effect on the rgb port, but not the b/w video out.
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Turned out to be my tv. I connected the amiga to my tv and the jumping picture happened. Connected my amiga to my pc via the capture card (same cables) and PERFECTION. Weird problem... It's a cheap polaroid tv that has been known to also turn only one channel on our satellite service purple. I assume it assume the tv won't hurt my amiga will it?
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Turned out to be my tv. I connected the amiga to my tv and the jumping picture happened. Connected my amiga to my pc via the capture card (same cables) and PERFECTION. Weird problem... It's a cheap polaroid tv that has been known to also turn only one channel on our satellite service purple. I assume it assume the tv won't hurt my amiga will it?
That was pretty weird. :) Reminds me of a time I somehow moved the brighness on my 1084 all the way down so there was no visible picture. I had an A2000 at the time. I tore it all apart, PSU out, and everything. I cleaned it all up, reseated chips, tried different configs of cards. Always a blank screen.
When I noticed the knob was turned down I felt totally stupid. Had a nice clean A2000 though.
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Turned out to be my tv. I connected the amiga to my tv and the jumping picture happened. Connected my amiga to my pc via the capture card (same cables) and PERFECTION. Weird problem... It's a cheap polaroid tv that has been known to also turn only one channel on our satellite service purple. I assume it assume the tv won't hurt my amiga will it?
You beat me to it. I was just gonna say I have an old Panasonic 68" TV that works perfectly with my A520 but my new'er 89" TV Jumps every so often and does the same B&W startup.
Thats why I got this : http://www.amigamaniac.com/RGB_to_PAL_NTSC_adapter.html Rock solid on s-video all the time with no colour satuartion probs.
BTW: The TV might hurt the Amiga if it topples forward. But apart from that unless your TV has curcuit problems we are talking millivolts here.
Gertsy
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Actually, this seems to only happen with the side inputs on my tv. The back ones are fine.
BTW, I was plugging my amiga into the tv's rear inputs, and I heard a buzzing noise from the tv as I accidently tried to plug the audio prong into the video jack. The amiga was off (power supply was plugged in but switched off), and I had left the tv on. Wikipedia says that RCA cables can cause equipment damage because the hot connection makes contact before the cold screening connection. However, I would think because the amiga was turned off it wouldn't hurt anything right?
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However, I would think because the amiga was turned off it wouldn't hurt anything right?
Actually, a simple connections to mains can be enough even if a device is switched off - if you're in very bad luck. The buzz you were hearing was proof that there was some voltage on the cable (there always is).
Connecting ground first is a smart way to equalize potentials w/o causing damage - unfortunately RCA jacks aren't built that way. It's good practice to switch off everything before connecting up.
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That was pretty weird. :) Reminds me of a time I somehow moved the brighness on my 1084 all the way down so there was no visible picture. I had an A2000 at the time. I tore it all apart, PSU out, and everything. I cleaned it all up, reseated chips, tried different configs of cards. Always a blank screen.
When I noticed the knob was turned down I felt totally stupid. Had a nice clean A2000 though.
It is hard to remember to always check the simplest things first. I am guilty of similar stupid oversights myself from time to time.