gmz@xroads.UUCP (Gerry Zeitlin) (02/14/91)
I've been advised by a local retailer to upgrade my rev 4.4 motherboard to the latest from Commodore (via a swap-out offer, approx $350 + installation). The reasons for doing this would include new memory timing (which would explain why the Aries memory board I just purchased there seems to be causing system crashes); fat Agnes; etc. Is this good advice? Might I be able to find another memory expansion system that would work ok with my rev 4.4 board? =gerry zeitlin= -- G E R R Y Z E I T L I N (602) 996-1661 Scottsdale Arizona (602) 996-1979 fax gmz@xroads.cts.com
daveh@cbmvax.commodore.com (Dave Haynie) (02/15/91)
In article <1219@xroads.UUCP> gmz@xroads.UUCP (Gerry Zeitlin) writes: >I've been advised by a local retailer to upgrade my rev 4.4 motherboard >to the latest from Commodore (via a swap-out offer, approx $350 + >installation). Sounds to me this guy's either misinformed, or just about for a buck. >The reasons for doing this would include new memory timing (which would >explain why the Aries memory board I just purchased there seems to >be causing system crashes); fat Agnes; etc. Well, I don't know why your new memory board is crashing, but there's no change in timing between old and new A2000s, other than the slight effect the ECS Agnus has on bus timing (all A2000b Agnus chips are Fat, the new ones are 1MB ECS Agnus). You can add an ECS Agnus to your R4.4 board and expect it to work just dandy. Two PCB jumpers must be changed to map the second 512K in as Chip memory. There is one known problem on some Rev 4.4 boards. In conjunction with a DMA driven hard disk, a certain brand of 74ALS245 chip used in the U605 position can cause an overly long rise time on the AS* signal out on the bus during bus master changeover. This is ignored by the basic A2000 anyway, but if the condition exists, it'll be a problem with accelerator cards that have their own DMAable memory, such as the A26x0 cards (since they respond to bus activity faster than Chip memory). This has the potential to cause problems with other memory devices, but none have so far been identified (unless maybe that's the problem with this Aries board; I know nothing about it). In any case, the fix is to add a 1K pullup resistor between pins 11 and 20 of the U605 chip, which is between the CPU and first Zorro II slot on your A2000. This fix is perfectly acceptible whether you have a problem or not, and it's the only difference between R4.4 and R4.5 A2000s. We pay less than 1 cent for such a resistor; I doubt Radio Shack could charge more than $1. As for R6 A2000s, no system timing was changed or anything like that. The main reason for the change was to replace the old 256K x 1 DRAMs used on the A2000 R4 and earlier with 256K x 4 parts, which became cheaper per bit. Some FCC changes were apparently made as well, I wasn't involved in that stuff. >Is this good advice? Might I be able to find another memory expansion >system that would work ok with my rev 4.4 board? Unless you have the aforementioned U605 problem, I wouldn't expect any trouble getting a correctly designed memory board to work fine in your system. And that U605 problem will only happen in conjunction with hard disk or other DMA. There is certainly no reason to pay $350 for a new motherboard! >G E R R Y Z E I T L I N (602) 996-1661 -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy "What works for me might work for you" -Jimmy Buffett
horalek@Alliant.COM (Jim Horalek) (02/15/91)
In article <1219@xroads.UUCP> gmz@xroads.UUCP (Gerry Zeitlin) writes: > >I've been advised by a local retailer to upgrade my rev 4.4 motherboard >to the latest from Commodore (via a swap-out offer, approx $350 + >installation). ... >Is this good advice? Might I be able to find another memory expansion >system that would work ok with my rev 4.4 board? > I've considered upgrading my motherboard as well but have resisted for the following reason. I haven't heard how much the New ECS chips are going to cost. Probably some $bucks. It might be better for CBM to distribute ECS on a new motherboard. Hopefully at a price less than $500 with installation. Of course if you can't wait you can't wait. How about it CBM? How are you doing to distribute ECS to the rest of the world? jim horalek@alliant.com Newsgroups: comp.sys.amiga.hardware Subject: Re: Rev 4.4 motherboard viable? Summary: Expires: References: <1219@xroads.UUCP> Sender: Followup-To: Distribution: Organization: Alliant Computer Systems Corp. Keywords: motherboard rev 4.4 In article <1219@xroads.UUCP> gmz@xroads.UUCP (Gerry Zeitlin) writes: > >I've been advised by a local retailer to upgrade my rev 4.4 motherboard >to the latest from Commodore (via a swap-out offer, approx $350 + >installation). >The reasons for doing this would include new memory timing (which would >explain why the Aries memory board I just purchased there seems to >be causing system crashes); fat Agnes; etc. > >Is this good advice? Might I be able to find another memory expansion >system that would work ok with my rev 4.4 board? > >=gerry zeitlin= >-- >G E R R Y Z E I T L I N (602) 996-1661 >Scottsdale Arizona (602) 996-1979 fax >gmz@xroads.cts.com
chris@zork.cc.binghamton.edu (Chris Peck) (02/15/91)
Well, I have a rev 4.3 motherboard (it has 4.1 silkscreened, but a 4.3 sticker on it). What kind of mods do I need to perform to add a fatter Agnus and have access to 1 Meg chip RAM??? thanks (I hope) -chris -- chris@zork.cc.binghamton.edu Chris Peck chris@bingvaxu.cc.binghamton.edu SUNY Binghamton, NY chris@bingvaxa.bitnet --"Any opinions expressed above are mine, ALL MINE!"--
gmz@well.sf.ca.us (Gerry Zeitlin) (02/17/91)
In article <18987@cbmvax.commodore.com> daveh@cbmvax.commodore.com (Dave Haynie) writes: >In article <1219@xroads.UUCP> gmz@xroads.UUCP (Gerry Zeitlin) writes: > >>I've been advised by a local retailer to upgrade my rev 4.4 motherboard >>to the latest from Commodore (via a swap-out offer, approx $350 + >>installation). > > >There is one known problem on some Rev 4.4 boards. In conjunction with a >DMA driven hard disk, a certain brand of 74ALS245 chip used in the U605 I have a GVP disk controller with a Quantum 40 Mb hard drive on the GVP board. Would this be the configuration that would cause the problem? Also, the 68000 chip on my motherboard is not the Motorola chip. It has a large "S" on it. I have heard that this chip is noisy and ought to be replaced with a Motorola chip. This was told to me by tech support at Preferred Technologies, who manufacture the Aries board. It certainly would be an inexpensive remedy. Think this could solve my problem? Thanks for your assistance! > >>G E R R Y Z E I T L I N (602) 996-1661 >
daveh@cbmvax.commodore.com (Dave Haynie) (02/19/91)
In article <23199@well.sf.ca.us> gmz@well.sf.ca.us (Gerry Zeitlin) writes: >In article <18987@cbmvax.commodore.com> daveh@cbmvax.commodore.com (Dave Haynie) writes: >I have a GVP disk controller with a Quantum 40 Mb hard drive on the >GVP board. Would this be the configuration that would cause the >problem? The old GVP controller didn't do any DMA, so it would not run into the bus handoff problem I mentioned. The new one might. If you're simply having problems with things running on the backplane, the first thing you want to check is the power supply. If the system isn't running very close to 5VDC with everything installed, you can expect problems. >Also, the 68000 chip on my motherboard is not the Motorola chip. It >has a large "S" on it. I have heard that this chip is noisy and ought >to be replaced with a Motorola chip. I don't think that we've ever had any particular problems with the Signetics 68000. I would not expect that to be a problem. -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy "What works for me might work for you" -Jimmy Buffett