Message-ID: <621@ncoast.UUCP>
Date: Fri, 1-Mar-85 18:01:11 EST
Article-I.D.: ncoast.621
Posted: Fri Mar  1 18:01:11 1985
Date-Received: Mon, 4-Mar-85 08:05:54 EST
Organization: North Coast XENIX, Cleveland
Lines: 22

[posted for my brother]

	The following is a description of the problem:
In the process of upgrading my 16k Model 4 to 64k with disk drives and RS-232,
I damaged the computer, blowing the fuse resistor on the power supply. As it is
now, the computer will not boot-up with the RS-232 installed. However, if the
RS-232 and disk drives are installed in the my Model 3 (from where I removed
them in the first place) the Model 3, RS-232, and disk drives function properly.
Even with the RS-232 disconnected from the Model 4, under Newdos/80 the drives
labor 3 to 4 times longer to format a disk (which is too short to run to the
bathroom and too long to sit and watch). Formatting seems to work normally under
Trs-Dos 1.3 (in Model 3 mode) or Trs-Dos 6.2 (in Model 4 mode).
	Once in Newdos/80 Basic I have connected the RS-232 to the Model 4 and
the computer works fine until it accesses the disk drives. Once in Trs-Dos 6.2
I have connected the RS-232 and the computer would work fine even when accessing
the disk drives. The mistake seems to have originated from the connecting
the ribbon cable from the RS-232 to the Model 4 off-centered.
	If any information can be provided to help me with this problem please
reply by net-mail. I do have a service manual for the Model 4.

						ADVthanksANCE,
						My brother Gary.

Message-ID: <263@unm-la.UUCP>
Date: Thu, 7-Mar-85 14:27:43 EST
Article-I.D.: unm-la.263
Posted: Thu Mar  7 14:27:43 1985
Date-Received: Sun, 10-Mar-85 07:16:25 EST
References: <621@ncoast.UUCP>
Organization: Univ. of New Mexico, Los Alamos
Lines: 24

 >  [posted for my brother]
 >  
 >  	The following is a description of the problem:
 >  In the process of upgrading my 16k Model 4 to 64k with disk drives and RS-232,
 >  .....

I work for a Radio Shack here in Los Alamos, and it may be that the easiest
solution to your brother's problem would be a trade in.  Radio Shack will take
trade in's on old mother boards and if you pay them around $80, they will give
you a fully functioning one.  

Of course, one has to weigh this price to that of sitting down with the tech
manual, a scope, a cup of coffee, and probably 3 or 4 spare hours just hunting
down the problem.  In the end, you wind up with a working board no matter which
route you take.

Best of luck...

Mike Mitchell

-- 
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/// Mike Mitchell @ [unmvax,lanl]!unm-la!cs193aat ///
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