on 1/29/03 10:11 PM, Jeff Walther at [EMAIL PROTECTED] wrote: Thanks for the pro answer Jeff (and Charlie). There are no blanks on the bottom, so I'm confident that it is an 8500. The tower it came out of has a part of the plastic inner frame that is black. I'm guessing that idiosyncrasy and the anomaly in the board silkscreening go together in some way. Not sure how. Maybe a rush order, early edition. If the frame was a collectors item, it's not now; got a lotsa extry holes in it. The TNT board has chips numbered 343S11(etc) so does the other one. They are both from 1995. The non TNT board has F2 rom, couldn't say about the TNT as it is out of the box and not likely to get back in for a while. >> "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
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