IBM Logic IC equivalency information needed

Santo Nucifora santo.nucifora at
Thu Jun 17 15:10:01 CDT 2021

To provide an update on the repairs so far, I've been able to save a few
boards while others are waiting for parts.

I was able to save a display card (I have two bad ones and one is waiting
for parts) and an APL ROS card which is really great.  All by replacing
some bad TTL logic chips.  I still have more work to do.

I also have two bad keyboards. It is the actual keyboard assembly as a
known working keyboard works fine.  I have taken them apart and cleaned
them as best I could but that didn't help.  One has exactly one key that
works (a slash key on the number pad) but no other keys register.  The
second keyboard doesn't register anything.  I am measuring this from the
keyboard connector on the keyboard mechanism.  One of the 5110's I acquired
had a full set of manuals but they were water damaged and the schematics
manual was one solid block of paper with all pages stuck
together, unfortunately.  I could really use some schematics.

Does anyone have any schematics for the 5100/5110 they can share?  There
are some schematics in the 5100 Maintenance Information Manual on Bitsavers
but they are more logical diagrams than actual schematics.  What I don't
know is if my "block of schematics" was like this as well.

Any assistance would be much appreciated.

On Sat, Jun 12, 2021 at 12:25 PM Chuck Guzis via cctalk <
cctalk at> wrote:

> On 6/12/21 1:58 AM, Christian Corti via cctalk wrote:
> > On Sat, 12 Jun 2021, Tony Duell wrote:
> >> I wonder if in the original list, a '1' was misread as a '7' or vice
> >> versa. I am told that in some countries the '7' is conventionally
> >> written with a crossbar across the downstroke to avoid this. My father
> >> always did this, for all it is not common in England.
> >
> > In Germany, we *always* write a bar across the 7. I don't like uncrossed
> > sevens because they are ugly ;-) and hard to distinguish from a 1.
> I do stroke my sevens just for clarity.   However, here in the US, few
> people write their ones with a serif--just a single vertical stroke.
> That, in my experience is not common practice in many European countries.
> Writing zero with a slash, by the same token, probably leaves the
> Scandanavian readers puzzled--as "oh" stroked is a letter of the
> alphabet.  Regardless, I stroked mine--a more universal practice might
> have been to write zero with a horizontal or vertical stroke.
> I recall turning in keypunch forms to be punched and receiving my job
> back with a note saying "I didn't know if you meant zero or oh, so a did
> some of both".   Wastebasket meet card deck.
> After that, I pretty much did all my own keypunching; management didn't
> like that, but I persisted.
> --Chuck

More information about the cctalk mailing list