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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: AmiJIm on December 07, 2005, 08:54:00 AM

Title: 1mb+ Chip RAM on A500 rev 6A / 8A.HELP!!!!
Post by: AmiJIm on December 07, 2005, 08:54:00 AM

Hi there,
i am having some trouble with the +0,5mb trick on the Amiga 500 Rev 8A.
On the pcb it has printed A500+ rev 8A fat agnus 8375
but hat has 0,5mb chip ram.
i soldered 4 chips M5M44256BP -8
ORIGINAL 4 CHIPS MB81C4256-10P

I DID THE jumper trick
but i still have 0,5 mb ram.,
Are the chips i used compatible?
Does anyone has 8 chips for sale?
or better yet 12 chips?
thnak you.

Title: Re: 1mb+ Chip RAM on A500 rev 6A / 8A.HELP!!!!
Post by: Cyberus on December 07, 2005, 09:05:05 AM

I haven't done this myself, but I recall there was some docs about this on Aminet, did you read them?

Title: Re: 1mb+ Chip RAM on A500 rev 6A / 8A.HELP!!!!
Post by: AmiJIm on December 07, 2005, 11:01:37 AM

Title: Re: 1mb+ Chip RAM on A500 rev 6A / 8A.HELP!!!!
Post by: Argus on December 08, 2005, 10:01:55 AM

Are you upgrading a rev 6 or 8?  The rev 6 upgrade just as easily uses a trapdoor 512K card and a couple trace cuts/jumpers to get 1MB chip.

Title: Re: 1mb+ Chip RAM on A500 rev 6A / 8A.HELP!!!!
Post by: Chain on December 08, 2005, 11:16:12 AM

ive done this hack on my 8A board without any prob.
i think all 256x4 chips are compatible (also 80ns+120ns etc)

Title: Re: 1mb+ Chip RAM on A500 rev 6A / 8A.HELP!!!!
Post by: Chain on December 08, 2005, 11:17:59 AM

Quote

or better yet 12 chips?

 :-o  where you wanna put it????

Title: Re: 1mb+ Chip RAM on A500 rev 6A / 8A.HELP!!!!
Post by: AmiJIm on December 09, 2005, 03:42:18 PM

Hi again,
i have both rev 6a and 8a.
Both have 512kb from factory
and both supports the above way of upgrading.
All i am asking is if the above codes on the rams are suitable for this trick,
i mean , are they 44256type?
Can you identify them??
I got them form ISA VGA cards.
thank you.