Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!sun-barr!newstop!texsun!letni!doug
From: doug@letni.UUCP (Doug Davis)
Newsgroups: comp.sys.tandy
Subject: Re: Model II, 12, 16
Message-ID: <7137@letni.UUCP>
Date: 10 Dec 89 06:15:48 GMT
References: <1392@ucf-cs.UCF.EDU>
Reply-To: doug@letni.LawNet.Com (Doug Davis)
Distribution: na
Organization: Logic Process  Dallas, Texas.
Lines: 47

In article <1392@ucf-cs.UCF.EDU> wordproc@ucf-cs.UCF.EDU (wordproc) writes:
>I have seen the innards of a Model II and a Model 16 on numerous occasions,
>either to work on them or whatever.
>
>The other day I saw a Model 12 with the back opened up, and was amazed at the
>fact that it did not resemble either the II or the 16 internally!  The boards
>and slots are mounted horizontally like the shelves in a bookcase rather than
>vertically as in the II and 16 machines.
>
First of all there are 6 machines in the same family, The models are
 2, 12, 16A, 16B, 16B+, and 6000.

The model's 2 & 16A had vertical card cages, the 16B[+]'s and 6000's had
horizontal card cages.  The model 12 however had no card cage, a card
cage "upgrade" was offered for model 12 users that wanted to
run XENIX or use the visicalc ram board, this effectivly turned the
machine into a 16B.  Since 16B's were really model 12's with factory installed
card cages. 16B+'s were 16's with one floppy drive removed and a 15meg
hard drive in it's place.  This machine had a special hard drive card
with both the interface and controler on the same board.   This is unlike
the normal hard drive board that was just an interface to the hard drive
controler which existed inside the case of an external "primary" hard drive.

Yes the original models had a slight heat problem corrected by a fan that
was installed by the local service folks. This was commonly called the
"turbo-fan mod"  Later machines, and all the B+'s and 6000's came out
with a factory installed fan that did the same job.

>Does the 12 take the same boards (hard drive controller and so forth) that the
>II and 16 take?  Why the different configuration?  
Obviously the z80 CPU, SIO, FDC, and Memory boards won't work in a 16B or 6000
since the Z80/memory, etc al. is on a board of it's own.  For this reason
the 16B/6000 machine had several more free card slots. 

>Seems like a good way to create problems with cards
>over a long period of time, with card bending and warpage and so forth.
Unless your machine has the "turbo-fan mod" you are very likely to run
into all sorts of problems, the least of which is card warping. 


doug 
"These opinions are my own and not Radio Shack's, who would like to
forget that they once sold machines that were not IBM compatable. Even
though they were faster, didn't have segment registers, etc..."
--
Doug Davis/1030 Pleasant Valley Lane/Arlington/Texas/76015/817-467-3740
{texsun, motown!sys1, uiucuxc!sys1 lawnet, attctc, texbell} letni!doug