greggt@ncoast.UUCP (Gregg Thompson) (03/02/85)
[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.
cs193aat@unm-la.UUCP (03/07/85)
> [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 -- ///////////////////////////////////////////////////// /// Mike Mitchell @ [unmvax,lanl]!unm-la!cs193aat /// /////////////////////////////////////////////////////