Path: utzoo!utgpu!water!watmath!uunet!lll-winken!lll-tis!ptsfa!pacbell!att-ih!ihnp4!ihlpf!gmark
From: gmark@ihlpf.ATT.COM (Stewart)
Newsgroups: unix-pc.general
Subject: Diffs 3B1/7300 - Conversion
Keywords: motherboard, RAM speed, HD power cable, hood
Message-ID: <3898@ihlpf.ATT.COM>
Date: 4 Mar 88 03:50:18 GMT
Distribution: unix-pc
Organization: AT&T Bell Laboratories - Naperville, Illinois
Lines: 39

I've been trying to determine the difference between the 7300
and the 3B1 and what actually is added by the swap of motherboards
and plastic hoods that are included in the conversion kit.  So
far I've been led to believe that the following is correct,
and would like anyone out there to confirm this:

The conversion kit consists of, of course, a new motherboard,
a new "high-top" hood, and a larger and faster hard disk.
It appears that the only reason for for this is that the installers
would have a devil of a time adding the additional 36 4256 RAM
chips to the multi-layer board, especially on site.  I have found
no indication in any of the documentation (so far) that there is
any difference in speed between the 36 chips on the existing
board and the 72 chips on the new one.  I have not been able
to see a difference on the schematic, so I suspect there are 
jumpers for this (I had a 7300 apart for only a few minutes).

As one can see from the specs, the replacement drives are considerably
faster than those installed in the 7300s.  

I see no difference in clock speeds, but I've heard that, although
the power supply is the same, the larger HD is connected via a
direct cable to the supply rather than via the motherboard.

The cost of the conversion kit, though seeming high, is pretty much
in keeping with the expected AT&T prices for the included components.

Note that many differences that people may see between machines MAY
be due to their having worked on different revisions, and not
due to the machines being 7300s nd 3B1s.

** SO, you expert UNIX-PC hardware hackers out there -- if I were
to swap the HD, add extra RAM (maybe just an expansion board -
I seem to remember seeing that the 1/2 Meg can be populated with
2Meg), swap the hood,  I would then have a 3B1, RIGHT?


				G. Mark Stewart
				ATT-BTL Naperville ix1g266
				979-0914 ixlpq!gms