a4000 wierd memory problem : help!

[Thomas]

Well, depending on board revision, the A4000 has either four RAM banks and chip ram soldered to the motherboard or five RAM banks with one of them holding 2MB chip ram. If your board has five banks, you have to let the chip ram in place, otherwise it won't boot. Green screen means there is not enough chip ram.

Bye,
Thomas

[Thomas]

If you don't have any device connected and no floppy disk in the drive it should at least show you the floppy animation. If it shows the yellow screen before that, something is wrong.

Well, in your first post you wrote that you had only the last memory chip in place and it showed you 512KB of memory. AFAIK even if you place a 4MB chip in the chip-ram socket, at least 1MB of it should be recognised. So this suggests that the chip is damaged indeed.

I am not sure how the memory logic reacts if you fit something different than a 2MB chip into the chip-ram socket. But I think if you put more than 2MB there, the full possible 2MB should be available.

Bye,
Thomas