Switching ROM version between A500 and A500+

[CU_AMiGA]

Hello,

My mate recently got himself an Amiga - 2 infact from a car boot sale. Firstly i will tell you the specs:

A500+  

With Kickstart and Workbench 2.04 with 1Meg CHIP RAM (default) and the 1Meg FAST RAM 501 upgrade.

A500

With Kickstart and Workbench 1.2 with 512K CHIP RAM.

The A500+ has a fault onit, the right audio port is very loose and no longer works. On the A500, the keyboard was {bleep}ed upas well as the casing. So i decided to switch some of the parts, i put the keyboard and casing from the A500+ and put the A500 mobo in and connected the keyboard. I also put the 501 expansion in and the A500 now has 1Meg RAM altogether.

Now, here was the problem. I tried to put the Kickstart 2 ROM from the A500+ and installed it in the A500 where the Kickstart 1.2 ROM was originally. Now, when i turned on the machine, i got a red screen (like James Bond), i know this means something, is it a Chip RAM problem? I installed back in the Kickstart 1.2 ROM and the A500 now works, but is it possible to change the ROMs around?

Cheers,

[Linchpin]

From another Site :

If there is something wrong with your system you may see the following colours.

Red: An error was found in the ROM.
Green: An error was found in Chip ram.
Blue: An error was found in the custom chips.
Yellow: The CPU has found an error before the error trapping software (Guru) has been activated.

[Linchpin]

And :

The red screen may be caused by a loose Kickstart chip that can be fixed by pressing down on the ROM to check it is fitted correctly. Another cause could be a connection problems between the chip and socket that can be solved by straightening an bent pins.

[x56h34]

If the Amiga 500 is of revision 5 and below then in order to accept a kickstart chip with 2.0 version and above, he needs to solder a wire between two pins on the kickstart rom itself. Don't quote me on this but I believe them to be pin 1 and pin 31. After that, it'll work.

[PaSha]

You may need to put a jumper wire between pin 1 & 31 on the 2.04 rom chip if the a500 mb is rev3 or rev5.

But: If the A500 is primarily to be used for games, then just leave the 1.2 kickstart in, the 2.04 kickstart will give you compatibility problems.

-Paul

[CU_AMiGA]

Hi Guys,

Thanks for the replies. Okay, if memory serves me i think the A500 mobo was a rev.5. So that was probably the reason (i had suspected this a little but forgot to mention). Anyway he told me he was using it for games mainly so i think its best it is left the way it is, which is a good setup for games. He's leaving the other Amiga for spares.