|Taking the opportunity to understand|
Message #6 Posted by Vieira, Luiz C. (Brazil) on 1 May 2003, 7:10 p.m.,
in response to message #5 by David Smith
It's always time to read and get precise information, and I always try to do it.
I read about ACT chips at this forum, about two years ago; I was not aware of some particular internal structures and from then on, I try to keep track with all, new information. I used to think when ACT chip was bad, calculator's overall operation was compromised, meaning it would act erratically. Based on these assumptions, I thought the ACT chip would carry the basic LED display control, KBD scan activity and number entering. ROM would be changed for each particular model. For example, HP27 and HP25 share everything except ROM; is it correct?
I thought if display is correct, number entering is fine but functions and/or memory is not O.K., then ACT chip is fine and ROM/RAM is failure. When my own HP25 was no longer able to hold numbers and programs (register would hold 0.00 and each program line was 13 00, whatever you stored there) and it was solved by resoldreing terminals, I was sure my "theory" was correct.
But I want both: helping with correct information and keep my own "babes" working fine. If I have given information that does not correspond to actual facts and as a consequence I may cause dammage to calculators that do not belong to me (and mine too), please, let me know for both reasons mentioned above.
I want to, please, call all contributors in here for correcting me anytime it's needed.
Thank you very much.
Luiz C. Vieira - Brazil