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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Loki762 on August 04, 2024, 07:49:25 PM
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First, I must admit that I don't know too much about Amiga, as I have always been more to C128/C64 - don't flame me ;D
However, I have bought a A500 that was in a quite rough (mostly cosmetic) condition. It only does have the standard 512Kb CHIP RAM onboard - no expansion slots or other modifications - this is as stock as it can get, I guess. Well, it did have a 512Kb RAM expansion, but there was too much corrosion on that and it gave a "Software Guru" error after ~30 seconds, so I have for now excluded that and the A500 is at least stable when powered up. I don't see any corrosion or damage on the A500 board anywhere.
My A500 is:
312513 rev. 6A
Assy 312510
When it boots up, then it does show the normal Kickstart 1.3 screen. I have tested with some floppies - most of them failing various sorts of ways, but I think this is due to bad floppies. I have though one floppy booting the first part, where it does show the intro or alike, so it seems to be working, except it cannot continue, but I think this could be due to COM1 is for sure broken, as it is missing some pins, so I cannot fully use the mouse or click with joystick.
However, I have downloaded the newest Amiga Test Kit 1.21 and when it boots then it just stops with a solid red screen.
I have tried touching all IC's, but none gets warm.
Is there any good advice on what I can try out to get rid of the red screen?
Do note that I do have a working A1200, as this is where I did write and tested the test floppy from.
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Normally a red screen means a kickstart problem. If there was a lot of corrosion on the memory expansion it's not unlikely there is corrosion in other places.
Though, looking at the pictures it seems like the ROM chip isn't seated properly. Might just be an illusion of course.
I would gently lift the ROM out of it's socket so you don't damage anything and then reseat it and push it down properly.
A decent way to lift these kind of chips without the proper tool is using a flathead screwdriver, insert it gently between the chip and the socket and twist the screwdriver. Don't bend, twist so the flathead does the job. Do this on both sides and the chip should come out easily.
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I have now tried resocket U6 (ROM) and put a lot of deoxit in the socket and on the IC legs. As mentioned then I cannot see any corrosion on the board itself and the corrosion on the RAM expansion was due to a leaked battery on it.
However, the red screen is still there. Could this be the IC/U6 itself being faulty? Or should I try and resolder the pins on it?
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Difficult to say of course. You mentioned that this happens with Amiga Test kit, what happens if you try to boot something else?
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When it comes to Test Kit 1.21, a few days ago someone reported same issue in Apollo Core Discord group with A1200, same floppy gave red error screen. No other disk.
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I have borrowed another floppy drive, and with this one it can boot Amiga Test Kit v1.21 without any issue. So I guess my floppy drive is worn-out.
Also sometimes it will not boot a bootable floppy and I need to reinsert the floppy multiple times, before it starts reading (and often it complains about read error).
When I have cleaned the drive as good as I can, is there then anything else I can try to get it in shape again?