On Sat, 6 Sep 2014, Pat wrote:

On Sat, 6 Sep 2014 14:26:28 +0100, "Arfa Daily"
wrote:

Anybody got a sheet for a Texas Instruments TMS3874 digital clock IC ? Loads
of references on the 'net, and people claiming to be suppliers and having a
datasheet, but you just finish up getting led down the path to companies in
China, with no sign of the actual sheet ...

Just the pin-out will do if nothing else available. It's a 'rescue' project
for a very old mate, so not desperately important, but it would be nice to
get it going for him again, as it was an apprentice piece that he built 38
years ago, and it has worked all that time until last week, when it just
suddenly stopped. I'm loathe to believe that the IC itself has failed, but
you never know ...

Arfa
I made a similar clock back in the day which still works well. It
originally used 7400 series TTL logic and Monsanto MAN-1 leds. A few
years later, I updated it to one of those "new fangled" clock chips.
Anyway, I just wenting looking for it in case it has the same chip,
but no such luck. It uses a National MM5311. There are plenty of
data sheets for that on the net, but not for your TI. Any chance the
pinouts are the same/similar?

It wouldn't have been a second source, so you can't trust it to be
"close".

The amusing thing is, if you went from ttl to an LSI clock, you missed the
step after that. A few years into the build your own clock phase, where
all those companies sold the needed parts and maybe a circuit board, the
semiconductor companies came out with clock modules, so all you had to do
was wire them to the power supply and some switches.

Michael