2 Aug
2011
2 Aug
'11
12:17 p.m.
Page 7-24 in TI 1971 set:
http://bitsavers.trailing-edge.com/pdf/ti/_dataBooks/1971_TI_IntegratedCirc=
uits/07.pdf
Expander gates will be about as clear as mud in the modern logic diagram se=
nse if you look at a single chip. Make sure to look up the 74H60 or 74H62 w=
hich is the "other half".
I shouid mention at this point that the signals between an expander and
the associated AND-OR-Invert gate are not normal TTL logic signals. They
are, perhaps straight onto the bases of transsitors. You can damage the
AOI if you short them to power rails in some cases.
This is something that many people working on HP9800 machines have
discovered the hard way. It gets a menion in my repair tips for such
machines as a result...
-tony