Upgrading an A500 to KS40/68 wb3.1

[Ral-Clan]

I have an Amiga 500 which has been upgraded to ECS and Workbench 2.05.  The hardware hacks were done at this time to make the Fat Agnes and Denise work and everything.

Are there any addition hardware modifications required to install a WB3.1 Kickstart chip in there, or is it merely a case of swapping the 2.05 chip for the 3.1 chip?

The reason I ask is because there is one of those kickstart switchers inside the A500 with the 1.3 and 2.05 Kickstart chips on it.  A few years ago I put the replaced the 2.05 chip with the 3.1 chip and I couldn't get it to work.  I put the 2.05 chip back in.

[zipper]

2.05 and 3.1 should be the same - in my A500 rev 6 they worked similarly.

[alexh]

Look at the 2.05 chip. Look at the 3.1 chip which didn't work. You should see a jumper wire on one and not the other... replicate the working one and voila.

Oh and it is 40.63 for A500 not 40.68!

[Ral-Clan]

Thanks guys.  I'll give it another try sometime when I have a weekend and a tinkering bug.

[zipper]

rev5 and older do need a modification into the socket.

[alexh]

rev5 and older do need a modification into the socket.

Not if they work with KS2.05 they don't. It would have already been done. Both 2.05 and 3.1 are 512Kbytes.

It's going to be the difference in EPROM chips, one will have had pins remapped the other not etc. or something like that.