Are these memory chips compatible with a500?

[ssr]

Hi...I found four km44c1000cj-6 chips...are these compatible with a500?...I have the full ecs board...but only 512kb chip ram...If yes, then what should I do (beside soldering them) to have 2mb chip ram?Thank you in advance

[alexh]

Unless you have an A500+, to get 2Mbyte chip RAM you will need a MiniMegi (http://bboah.com/cgi-bin/showhardware.cgi?HARDID=985) / MegaChip (http://bboah.com/cgi-bin/showhardware.cgi?HARDID=992) agnus upgrade. These are very expensive and it would be cheaper to buy an A1200.

You can upgrade your setup to 1Mbyte Chip RAM though. The procedure to upgrade will differ depending on your motherboard revision.

http://www.textfiles.com/computers/500hacks.txt

[ssr]

I have the a500+ board in my a500.

[alexh]

I thought that all A500+ came with 1Mbyte of ChipRAM by default??

Show some pictures of your board.

You should be able to add the extra 512K bytes to your motherboard to make 1 Mbyte chip RAM and then get an A501+ expansion for the trap door. With a lot of soldering you could in theory add 2Mbytes directly to motherboard but why bother?

HOWEVER

km44c1000cj-6 is a 1Mx4 (512 Kbyte) device , ideally you want 8 * 256Kx4 (128 Kbyte) devices such as a TMS44C256.

http://bboah.com/download_photos/a500plus_rev8a1_5.jpg

The pinouts might be compatible and it will just not use the extra RAM (i.e. each chip will be treated as a 256Kx4) but just look at the pinouts of the two devices.

[ssr]

:)I don't have a normal a500+ but an a500 with the a500+ board...it says 'a500+ rev8a.1'...but the kick and ram like in a500...here is a hack for a2000 that uses four 1MB x 4 memory chips...so I thought that in an a500 they could work too...http://mylinuxisp.com/~jdbaker/oldsite/documents/2MBAgnushack_v1.4.txt

[Paul_s]

I thought that all A500+ came with 1Mbyte of ChipRAM by default??

Show some pictures of your board.

You should be able to add the extra 512K bytes to your motherboard to make 1 Mbyte chip RAM and then get an A501+ expansion for the trap door. With a lot of soldering you could in theory add 2Mbytes directly to motherboard but why bother?

HOWEVER

km44c1000cj-6 is a 1Mx4 (512 Kbyte) device , ideally you want 8 * 256Kx4 (128 Kbyte) devices such as a TMS44C256.

http://bboah.com/download_photos/a500plus_rev8a1_5.jpg

The pinouts might be compatible and it will just not use the extra RAM (i.e. each chip will be treated as a 256Kx4) but just look at the pinouts of the two devices.

Alex, out of interest where do you buy your 256x4 components from? I'm looking at doing this to one of my 500 rev. 6 boards. Cheers :)

[Zetr0]

@Paul s

you can get them from dead A500's or dead A501's, however if you feel like you are looting a corpse you can get them from

Futurlec.com (http://www.futurlec.com/ICRAM.shtml) (bottom of the page either 514256 or 41256) you will have to confirm as one is 20pin the other is 22 pin.

theres no minimum order and delivery is $5 takes about two weeks :)

[alexh]

Of course you can get them off ebay for about $3 per chip which IMHO is daylight robbery!

[rkauer]

OR, as I did, take a very dead A2091 (SCSI chip broken) and take the 2Mb of memory from it. :spin

I still use the dead A2091 on mine A2000 without the SCSI and the Gayle chip as a HD holder(!), works OK. :xmas

[alexh]

Aint no Gayle on an A2091

[rkauer]

@Alexh: oops! DMac! :o