Any HP80-seires experts around?
ard at p850ug1.demon.co.uk
Sun Jun 13 12:51:57 CDT 2010
Are there any HP80 seires experts here? I've got a curious quesiton.
I am looking at the HP82909 128K RAM module (for the HP86/87 series).
There are several places on the PCB that are not used -- from memory,
thre are 4 locations for 14 pin ICs. More curiously, there's a place for
a rssistor and transsitor to drive the ROMDIS/ line on the computer
I am pretty sure the 'missing' chips are simple logic functions. One is
very probably a '74. Another may well be a '30. But I haven't worked out
the details yet.
My guess is that some HP product actually used this extra logic. So my
'curious quesiton' is : What product was it?
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