Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site ncoast.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!bellcore!decvax!cwruecmp!atvax!ncoast!greggt From: greggt@ncoast.UUCP (Gregg Thompson) Newsgroups: net.micro.trs-80 Subject: Need help with Trs-80 Model 4 hardware repair 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.