ccgavin@uqvax.decnet.uq.oz (08/14/90)
In article <13645@cbmvax.commodore.com>, daveh@cbmvax.commodore.com (Dave Haynie) writes: > In article <3223@rwthinf.UUCP> stefanb@cip-s02.informatik.rwth-aachen.de (Stefan Becker) writes: > >>Is it possible to upgrade the A3000 to 4MB Fast-RAM with 1Mx4 DIP(!!) chips, >>which replace the existing 256Kx4 DIP chips in the first bank? > > Two problems here. First of all, I'm not certain that the DIP bank was > wired for the extra address line necessary for the 1Mx4 parts, though there > is a good chance it was. The second problem is the one to overcome -- find > a source of 1Mx4 DIPs in 0.300" packages. At least back when we had to make > this kind of decision, only one company had announced a 1Mx4 DIP part, at it > came in a 0.400" package, which of course isn't physically compatible with > the thinner DIPs we're using, even if the pinout is the same. ZIPs aren't a > problem, since they grow vertically rather than horizontally. Anyway, if > 1Mx4 0.300" DIPs start to show up, I can easily check to see about whether > they work in the A3000's Fast-Bus DIP sockets. Is the revision 6 A500 mainboard wired for the extra address line to support 1Mx4 DIPS. Also is there any modification needed other than replacing the current 256kx4 DIPS with the 1Mx4s to produce a 2M chip ram A500, as the Agnus chip in the rev 6 boards is supposed to be the same as in the A3000 that supports 2M chip ram. Thanks in advance, Gavin............. -- Internet: ccgavin@uqvax.decnet.uq.oz.au Phone: +61 7 377 3025 Postal: Gavin Stone-Tolcher, Prentice Computer Centre Queensland University, St Lucia, QLD Australia 4067.
finnis@WELSWS.enet.dec.com (Peter Finnis) (08/16/90)
> Is the revision 6 A500 mainboard wired for the extra address line to >support 1Mx4 DIPS. Also is there any modification needed other than replacing >the current 256kx4 DIPS with the 1Mx4s to produce a 2M chip ram A500, as the >Agnus chip in the rev 6 boards is supposed to be the same as in the A3000 that >supports 2M chip ram. > Can You expand the 256x4 to 1 Meg on board plus the 512kb Trapdoor to give 1.5 Meg ?? I presume this requires the Fatter Agnus (02) , But what links do you add/cut .. Rev 6A motherboard Amiga 500 only.. ___ / / Peter Finnis /__/__ _/_ __ Digital, Shire Park, The Boulevard,Welwyn Garden City, / /_/ / /_/ England. / /_ /__ /_ finnis%welsws.dec@decwrl.dec.com Phone: 0707-374174