Posts: 40
Threads: 7
Joined: Jan 1970
Have anyone the HP75's schematics?
Or where can I find them?
I'm examining the possibility to build some expansions (RAM and ROM) for my HP75D. So I need of documentation as much as possible (included the electrical schematics).
Thanks.
Claudio.
(as always delete the two "_nospam_" from e-mail address :-) )
1234
Posts: 1,162
Threads: 26
Joined: Aug 2005
There is an HP75C service manual, which includes schematics and bus timing data (for all 'service' meant board-swapping if you were HP). I am pretty sure this manual was available to the public at one point (it was mentioned in PPC journal), so there's probably somebody out there who has both the manual and a scanner.
Posts: 40
Threads: 7
Joined: Jan 1970
Wow, it seem very interesting!
I hope that someone can post it to all the community!
Claudio
1234
Posts: 4,027
Threads: 172
Joined: Aug 2005
Posts: 785
Threads: 13
Joined: Jan 2005
I own a HP-75C...but what is inside?
[VPN]
Posts: 2,309
Threads: 116
Joined: Jun 2005
Quote:
I own a HP-75C...but what is inside?
A bunch of HP custom CMOS chips, including the microprocessor (a CMOS version of the HP-83/85/86/87 "Capricorn" microprocessor), ROMs, display drivers, bus drivers, keyboard controller, clock and alarm, card reader, HP-IL (1LB6 rather than 1LB3), etc. And some industry-standard 2K*8 SRAMs, HM6116 or equivalent.
Posts: 40
Threads: 7
Joined: Jan 1970
Really haven't anyone them? :-((
I'm particularly interested to the expansion slots for the RAM and the ROM.
Claudio
1234
Posts: 1,788
Threads: 36
Joined: Aug 2007
And inside of each of those custom IC's is... magic smoke. Once you let the smoke out of a package it quits working.
Posts: 1,162
Threads: 26
Joined: Aug 2005
I have the HP75C service manual, what I don't have is any way to scan it :-(
Posts: 40
Threads: 7
Joined: Jan 1970
Arghhhhh #@ยง!%$#&!#
I'm always unlucky!! ;-)
Claudio
12345