Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!elroy.jpl.nasa.gov!usc!rutgers!cbmvax!daveh From: daveh@cbmvax.commodore.com (Dave Haynie) Newsgroups: comp.sys.amiga.hardware Subject: Re: 2052 problem? Message-ID: <22737@cbmvax.commodore.com> Date: 27 Jun 91 15:17:43 GMT References: <1991Jun20.170531.23159@newserve.cc.binghamton.edu> Reply-To: daveh@cbmvax.commodore.com (Dave Haynie) Organization: Commodore, West Chester, PA Lines: 28 In article wemmpd@cutmcvax.cs.curtin.edu.au (Peter Wemm) writes: >Add me to the list too, I have a sick A2052 as well.. I am lucky enough to >get random bit-cell failures AT ANY TIME! My system is an OLD A2000 (with >a 48-pin Agnus), A2090, and a 1 MEG ram card in the CPU slot. It WONT run >a CPU accelerator card. A couple things to know about the A2000-a boards. First off, there was a bug in the bus control PAL of many of these, which causes major problems if you have DMA to an expansion bus memory card. Technically speaking, the bus buffers between the motherboard local bus and expansion bus are supposed to be off, or pointed toward the motherboard, during an on-expansion-bus DMA transaction. On the original A2000-a, they're actually pointed at the expansion bus, so you get data bus buffer fights between the DMA device or RAM card and motherboard buffers on every cycle. They released a PAL that fixes this, which was shipped with A2090s once they knew about the problem. As for accelerator cards, the old A2000-a's don't have a full fledged Coprocessor slot. You can't run any accelerator board without removing the 68000 from the motherboard, and some accelerator cards aren't designed to work in this system at all. The A26x0 boards do work, though you need to change three jumpers on the A2620, one jumper on the A2630, and of course remove the 68000. Those are the problems I know about with that system. -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy "This is my mistake. Let me make it good." -R.E.M.