IBM 5120

Guy Sotomayor ggs at
Sun Jul 12 17:06:10 CDT 2015

I had acquired an IBM 5120 a few months ago but I didn’t have time to really check it out.

It’s a fairly pristine example (32KB) with dual 8” floppies.  It also came with a few manuals
including the Maintenance Information Manual as well as the Computing System Logic
Manual (still shrink wrapped).  It also has a serial I/O diskette and a diagnostic diskette.

It also came with a printer but I have not yet unboxed that yet.

When I originally unboxed the 5120 I was a bit disappointed in that the shipper didn’t pack
it as well as I would have liked (styrofoam peanuts) but there was other packing material
so it wasn’t a complete disaster.

Since it was a working unit prior to shipment, after an initial inspection, I powered it up only
to have nothing happen.  :-(  I proceeded to take the covers off and noticed that the fuse
for the display had blown.  It was likely vibration related since I didn’t see nor smell any
burnt components.  Replacing the fuse, I saw that the cathode filament was lit but still nothing
on the display.  :-(

After removing the logic chassis and removing all of the foam “gunk”, I noticed that a couple
of the boards as well as the connectors for two of the boards were loose.  After reseating
everything, success!

I haven’t yet done a complete checkout yet, but I did enter a small BASIC program and it
ran successfully.  Now I have to find some IBM formatted 2D diskettes for this so that I can
save what ever programs I enter.  ;-)

TTFN - Guy

More information about the cctech mailing list