A500 1mb Chipram Upgrade - Trapdoor problem

[Amicol]

Hi Chaps,

I was bored so decided to upgrade my A500's chipram to 1mb.
I did this by adding 4xchips to the motherboard (rev 6a)

I then altered JP2 to make the board recognise the additional 512kb.

Here's my issue.

Now the machine will not boot with the 512kb memory expansion in the trapdoor.
Are further mods necessary to get it to work?

Cheers

[zipper]

Yes - your mobo addition overlaps the trapdoor one afaik.

[Amicol]

Originally Posted by zipper

Yes - your mobo addition overlaps the trapdoor one afaik.

So I might as well sell the 512kb expansion card now as it's quite useless?

[Brannigan]

You have a clock on the expansion board you want to use?

I think JP7A is used for relaying a signal from the expansion board to indicate the presence of RAM. If you cut open the lower and mid pads of the jumper you should be able to disable the expansion RAM but still be able to use the clock. In theory at least.

[Amicol]

Originally Posted by Brannigan

You have a clock on the expansion board you want to use?

I think JP7A is used for relaying a signal from the expansion board to indicate the presence of RAM. If you cut open the lower and mid pads of the jumper you should be able to disable the expansion RAM but still be able to use the clock. In theory at least.

Unfortunately it's just a 512kb expansion, no clock. eBay it goes.....

[Promilus]

With ReSlow or RangerMem mods you can use it as 512KB 0C000000 memory (slow mem range) with 1MB chip on-board however those mods aren't quite as reliable (no one can guarantee they'll work for you).

[Sandro]

Originally Posted by Amicol

Unfortunately it's just a 512kb expansion, no clock. eBay it goes.....

no clock? then do not worry about it, remove the expansion and use it with 1mb chip
some games that requires 1mb chip now will work, example dracula, turbotrax etc