On Tue, May 20, 2025 at 2:38 PM Bill Gunshannon via cctalk <[email protected]> wrote: > > > I just managed to score a 5155. Well, soon, it is waiting for me to > pick it up at the University where I used to work. It looks to be in > really good shape and has been in storage for probably two decades or > more.
I restored one last year. Mine is still 100% orginal IBM too. It's a normal PC/XT motherboard with CGA and floppy controller boards at least. Technical references for everything apart from the power supply are on bitsavers. Theres another site with some detailed information on the power supply and I think I found the sources for the keyboard microcontroller as a Github project. > > A couple quick question for anyone familiar with this system. > > Is it likely there is one of those little batteries on it that would > now be dead and need replacing before I try to use it? No, it's a XT, so no internal real time clock or CMOS configuration RAM as standard. What you do need to replace before they do their antisocial acts and emit clouds of magic smoke are the metalised paper capacitors in the power supply. This is painful to do, you have to dismantle the power supply which involves Bristol Spline and tamperproof Torx screws, then drill out rivets holding the little filter PCB in place. Rivets that are hard to get a drill to. The only other part I had to replace in mine was a tantalum bead capactor on the motherboard. > > And, also, would this have a floppy controller on it that was capable > of reading and writing disks from systems like the TRS-80 with an SD > boot track? Alas not. The oriignal IBM controller is strictly double density (MFM) only. -tony
