Determining Health of A4000 Mainboard

[patrik]

1. Do you have the stock doublesided 2MB SIMM to try with as chipmem, just to be sure there arent any compatibility issues?
2. Are the motherboard INT/EXT jumpers set to EXT for use with the A3640?

The colours, especially if they arent consistent will not tell you more than that "something" is wrong.

Also even if you get one consistent colour, it is not a very precise indication of what is at fault - say if you get a green screen for chipmem error, it might not be the chipmem itself which is at fault, but something else needed to make it function. Say in the case of the A500/A2000/A3000 a green screen more often means that there is oxidation and bad contact in the Agnus socket. This should not be the case of the A4000 as Alice, the Agnus equivalent in the AGA chipset is soldered to the motherboard, but I was just making an example.


/Patrik

[patrik]

@irishmike:

The INT/EXT jumpers are a pair of jumpers (two) located on the motherboard, under the processor card, so you need to remove it to get access to them. They are marked as INT/EXT on the motherboard in white, printed letter.

The chipmem simm need to be doublesided to give you a full 2MB of chipmem. If not - say if you use a singlesided 4MB simm, you should get 1MB chipmem, but the computer should still work. Usually a doublesided 8MB simm works. Parity is ignored.


/Patrik