Re: HP34C Chips positions ? Message #4 Posted by Vieira, Luiz C. (Brazil) on 27 Nov 2002, 9:43 p.m., in response to message #3 by David Smith
Hi;
I believe you're right about ROM's and RAM, mostly because the separate IC has its poer pin comming straight from the power supply connector, and the others share their power pins with the CPU. I guess this two IC's should be ROM and the first one is RAM, powered directly.
I have an HP33C guts and I had a look at their IC's an mainboard. The topmost IC is an 1LB901, and the remaining other (only one, button position) is an 1MA something (unreadable). As the HP34C has two 1MA IC's and one 1LB, I guess their position is:
1LB902
1MAxxxxx
1MAxxxxx
Would you try this configuration, Pyerre? Now that I see the codes you posted first, it seems to me the different prefixed IC (1LA) would go in the different position, as the other two share the same prefix (1MA; probably ROM).
Hope you have success. Let us know about it!
Cheers.
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