4mb Ram expansion for A500 question

[Dingo_aus]

I was wondering if anyone has used the "Expansion" (name of the company) 4MB "base board" system?

I'm mostly interested in whether the thing comes with 4MB or was just a board that you had to add chips to.

This is the one I'm talking about:

Base Board

Thanks

Dingo_aus
Brisbane, Australia

[doctorq]

Most likely it came with none or 512 kb of ram, so people could upgrade in case they needed it.

[mechy]

hello,
    this is from memory,so take it with a grain of salt ) The baseboard(by expansion systems) was designed to map the first 512K to chip ram,then you have the remaining left to use.its also got a realtime clock,if the battery is present.
generally i think they came with anywhere from 0K to 4M.
they use the 256x4 chips,same as the A590 and some other ram cards.

basically you can have up to 3.5M fastram. i have found these to be a bit flakey when used with a A500 that you have added the 512K on the motherboard(revision 6 a500)
you may have different results.

this card was also sometimes restickered as a "rapid access" and sold by other companies. same board.

it plugs into the belly slot and the smaller part of the board goes under gary(gary chip plugged into the socket on the small board),and there was also a jumper,but i can't recall where it went,i think it was for int2 off one of the cia chips.i have had luck running without it,but may be specific for the motherboard revision.

be sure u set the agnus jumpers etc properly.

hope that helps
    Mike

[number6]

@thread

I have used this product, along with the additional 2MB daughterboard since it was initially released.
For more hardware and software info:
http://amiga.resource.cx
Type "Baseboard" into the search engine

I even used this hardware/software combination in conjunction with MegaMidget Racer hardware/software.
I never saw a problem.

Best Wishes,
#6

[TjLaZer]

Mechy is correct, with 4MB installed you can have 512k as Chip giving you 1MB Chip and 3.5 Fast.  And the Fast is not contigious so it comes up as 512k chunks, it also does not autoconfig, you have to run a command at startup to add the ram.  But it seems to be working fine for me see my photo gallery for pics of it installed in my A500!

[number6]

@TjLaZer

And if you are fortunate enough to have the daughterboard (XRAMBoard - 2MB), then, as stated
in the manual, "If you are a user that requires the largest block of contiguous memory at the
expense of any of the other conveniences, there is an optional mode that will provide 5.5MB or
6.0 MB contiguous blocks."
This requires the "C" pal chip supplied with the daughterboard and the addition of a "contiguous jumper".

Best Wishes,
#6

[Dingo_aus]

Thanks for the very detailed response!

It helps a lot.