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Stedy · 18 November 2018, 00:50

Hi,

You have a defective solder joint on one of the address lines to the DRAM. The regular pattern of the stippling indicates it is a higher bit. If the RAM can not be read from or written to reliably the Amiga will crash. The floppy drive is read and the data buffered by the RAM, which is defective, hence the issues you see.

I identified the problem as to create a graphics display, you read the framebuffer, which is part of the chip RAM. If there is a faulty data or address line you will see a regular pattern as shown in your screen shot. A defective data bit show up as more corrupted pixels, an address bit shows up as corruption at set distances apart.

Check the RAM devices in your A500, look for any dull colour solder joints, contamination or short circuits. You do not need to recap this yet.

18 November 2018, 00:50	#3
Stedy Registered User Join Date: Jan 2008 Location: United Kingdom Age: 46 Posts: 733	Hi, You have a defective solder joint on one of the address lines to the DRAM. The regular pattern of the stippling indicates it is a higher bit. If the RAM can not be read from or written to reliably the Amiga will crash. The floppy drive is read and the data buffered by the RAM, which is defective, hence the issues you see. I identified the problem as to create a graphics display, you read the framebuffer, which is part of the chip RAM. If there is a faulty data or address line you will see a regular pattern as shown in your screen shot. A defective data bit show up as more corrupted pixels, an address bit shows up as corruption at set distances apart. Check the RAM devices in your A500, look for any dull colour solder joints, contamination or short circuits. You do not need to recap this yet.