>Date: Thu, 30 Jan 2003 07:44:08 +0800 >From: Charlie Reyes <[EMAIL PROTECTED]> >Subject: Re: 8500 boards > >"R.A. Cantrell" <[EMAIL PROTECTED]> wrote: > >> What's the difference between these 8500 boards? One is an >>820-0564-09 TNT Motherboard VAL-4 the other is an 820-0752-A. Is one >>"better" than the other? I am going to assemble my 8500 project and have >>these two (and more) boards to choose from? >>-- > >Did you say "TNT" - suitable for 7500, 7600s? 8500s use "Nitro" boards >which differ by having an extra chip (Sixty6) to handle video out topside >between PCI and VRAM slots. I can only guess the difference between them >may be ROM revision with the one ending in F2 newer than F1.
But the printed circuit boards (7x00 vs 8500) would probably have the same identifier silk screened on them. All of the above mentioned machines use the same printed circuit board. The only difference is a couple extra chips installed on the 8500 assembly line. So I don't think TNT vs. Nitro markings on the PCB would be definitive because whether a given PCB would become a TNT or a Nitro was probably an accident of which box got stacked where, long after the silk screening was applied to the boards. It does sound like there was a revision some where since RA has two different part numbers there, but I don't think it's a 7500/7600 vs. 8500 distinction. I don't know what happened between those revisions. I do remember folks had a low opinion of the VAL-4 boards, but I don't remember why and I remember there being a lot of doubt as to whether the opinion was justified. The four ROM chips on these boards are on the underside. A $77D.28F1 revision would be labeled 341S0106 through 341S0109. I've only ever seen this revision on 7200s but that doesn't mean it doesn't exist on 7500s or 8500s. The $77D.28F2 chips are labeled 341S0168 through 341S0171. The 7500, 7600 and 8500s I've seen all use the F2 ROMs. And I've seen some of the F2 ROMs installed on 7200s as well, strangely enough. This is one way to distinguish an 8500 from an early 8600 board. The 8600 ROMs will be labeled 341S0280 through 341S0283. Of course, it's easier to look at the power supply connector. :-) But to get back on topic, I don't know the answer to RA's original question. I mainly wanted to illuminate the ROM revision topic. To answer his question from a later post, not quoted above (I'm on digest) look on the top of the board. If it's a 7500 or a 7600, near the center back of the board there will be two outlines for chips with no chips installed. If it's an 8500 the chips are installed. If they're not installed it's a 7500 or 7600. That's the only difference. Jeff Walther -- PCI-PowerMacs is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Refurbished Drives | -- Sonnet & PowerLogix Upgrades - start at $169 | & CDRWs on Sale! | Support Low End Mac <http://lowendmac.com/lists/support.html> PCI-PowerMacs list info: <http://lowendmac.com/lists/pci-powermacs.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/pci-powermacs%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
