A520 Juming Screen Only Before Workbench

[Super TWiT]

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?

[som99]

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.

[CSixx]

Sounds like you have a pal A520, the black and white display is a typical effect.

[som99]

Yepp, depending on where you live I can send you a PAL A520 for free if you pay postage

[rkauer]

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.

[Super TWiT]

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?

[Amiga_Nut]

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?

[Super TWiT]

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.

[Super TWiT]

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?

[Super TWiT]

Is the quick red screen a new clue?

[Zac67]

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.

[Super TWiT]

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?

[AmigaHeretic]

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.

[Super TWiT]

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.

[AmigaHeretic]

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.