I need information about Voyagers IC's Message #1 Posted by Vieira, Luiz C. (Brazil) on 3 Oct 2002, 11:33 p.m.
Hi;
I've been resurrecting one old Voyager and I intend making an internal trading.
The to-be-resurrected Voyager is an earlier HP15C, with the electronics built in a flex-PCB (I gave up trying to recover the flex-PCB; it has many broken trails, others are no longer bonded to the flex board and the LCD shield already has two broken claws) . I have an old HP11C that no longer works, and it is a newer model. After removing all bezels and both logos, I am ready to trade their guts. But I'm afraid the HP15C's keyboard scanner is not working, and I am almost sure the HP11C's equivalent IC is working. But both HP11C and HP15C's keyboard scanners have different codes!
The Voyagers (I do not know the HP10C internals, so I'll refer only to the HP11C, 12C, 15C and 16C) have two basic IC's: the R2D2 (RAM/ROM & Display Driver), that is a big one and is built in the opposite side of the LCD, and the keyboard scanner, that interfaces the keyboard and R2D2.
The fact is that I opened some newer voyagers (an HP12C and both HP15C and HP16C) and I became confused. In these machines, the keyboard scanner is the same as the one found in the HP11C (except for the Malaysian HP12C, which has only one VISIBLE all-in-one IC). All of these IC's in the newer calculators are built in one single PCB that accommodates all electronics: KBD contacts, IC's, LCD and the three external components. The table bellow summarizes all IC's codes for these Voyagers.
KBD scanner R2D2 ??? (third HP15C's IC)
earlier |
HP15C | 1LF5-0301 1LE2-0321 1LH1-0302
|
newer |
HP15C | 1LM2-0001 1LH1-0306 1LH1-0302
|
HP11C | 1LM2-0001 1LH1-0305
|
HP16C | 1LM2-0001 1LH1-03xx (I'm not sure; printing is too light)
|
newer |
HP12C | NONE(*) 1RR2-0001
(*)2001 model, made in Malaysia
I remember trading posts with Tony Duel about the third HP15C's IC. We may notice that only the HP15C has it, and those who deal with the HP15C know that it has a bigger memory capacity when compared to the others (67 registers, I included; about three times the memory available in the other voyagers). The organization of the HP15C's memory lead to some conclusions. In the HP15C, registers I, Ro and R1 are built in the R2D2 (RAM/ROM Display Driver, as Tony mentioned); all others have all memory in this same IC, as they share the same keyboard scanner and do not have the third IC. So, in both HP11C and HP16C all RAM is contained in the R2D2. I cannot see another possibility than the third HP15C's IC being the 64 registers block. As a coincidence, some operations available in the HP15C that deal with registers use only one byte of program memory when addressing registers I, R0 and R1, needing two bytes for the other registers (2 to .9). These functions are x<>, DSE and ISG. I know this is not a proof of this reasoning, I just call the attention for the coincidence. I also agree with Tony that part of the HP15C's ROM is built in this IC, too.
My major concern is the following. Both earlier and newer HP15C use the same third IC: 1LH1-0302. Signal levels and control lines must be the same from this IC to the others. I also checked the board, and all visible connections are the same. I'm gonna remove the 11C's IC's from its previous board and place the 15C's IC's there. All I want to know is if anybody have already mixed the earlier 15C's IC's (1LF5-0301 and 1LE2-0321) with the ones in the newer 15C (1LM2-0001 and 1LH1-0306), say, earlier KBD controller with newer R2D2 and vice-versa. If it works fine, I'll have to transfer only two IC's instead of three, and this procedure not only eases the job but also involves less risk to the components.
If anybody already had this experience, please, let me know. I'm delving into this "guts transplantation" next week, so I'll have time to think about it and read related posts. If there is any confusing explanation, please, let me know. I believe I wrote everything correctly, but... you know what I mean! I know Portuguese by heart...
Thank you a lot.
Best regards.
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