Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!wuarchive!sdd.hp.com!caen!hellgate.utah.edu!csn!ub!dsinc!bagate!cbmvax!daveh From: daveh@cbmvax.commodore.com (Dave Haynie) Newsgroups: comp.sys.amiga.hardware Subject: Re: Jumpers on B2000 REV 4.2 (?) Message-ID: <22383@cbmvax.commodore.com> Date: 13 Jun 91 01:24:24 GMT References: Reply-To: daveh@cbmvax.commodore.com (Dave Haynie) Organization: Commodore, West Chester, PA Lines: 41 In article clemon@lemsys.UUCP (Craig Lemon) writes: > As a spinoff on the recent discussion about the jumper setting of >J300 for video purposes, I was wondering if anyone (possibly Dave) could >assemble and post (or mail me) a list of what all the jumpers in the B2000 >are. I have REV 4.2 so I am obviously interested in that but no numbers >should have changed throughout the B2000 line I don't think. J101 Select A19/A23 for second Agnus RAM bank select J102 Enable NTSC mode on ECS Agnus, disable test on 512K Agnus J200 Select port 0/port 1 lightpen J300 Selects LINE/VSYNC TICK source J301 Enables 3.5" 880K ID code for DF1: J500 Enable for decoding of $00Cxxxxx as RAM J900 Enable Chip RAM slowdown during DMA I think that's all. >Where is the clock circuit? I'd like to know for two reasons - this >adjustment and for when I may need to replace the battery. I saw a yellow >coloured trim pot at the very front of the case in line with the >Co-Processor slot, is this is? That's it. It's actually a trim cap. The battery is the funny looking blue thing to the right of it. It's a nicad, supposedly good for 10 years or thereabouts. > Also, again, Which chip is Kickstart. I'm still running 1.2 while >waiting for 2.04 (or whatever) to be burned and I haven't had to touch it. >It is not labelled on my motherboard. I think that it might be the >socketed chip at the mid-rear of the motherboard. No, I think you're looking at Gary. The ROM is on the right of the 68000. -- 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.