Message #1 Posted by Vieira, Luiz C. (Brazil) on 12 Sept 2001, 12:43 p.m.
About 10 years are past since my (at that time) recently bought HP16C lost two columns of operating keys. They were <D> to <STO> and <0> to <7> columns. I opened the calculator and could see that the 10 Series keyboard is, in fact, a 8X5 instead of a 4X10 matrix (1 control line less?), with folded, symmetrical columns. My 16C is the one with a complete, all on board PCB, no flex print for the display and ICīs. I tracked all PCB and I figured out that the keyboard scanner IC (dont remember the ID #) was faulty, not the kbd PCB. I had also a broken HP11C that I latter used to trade for a new HP32S with Hewlett Packard, in a time HP bought our old models as we bought their new ones (at least here, in Brazil, late in 1980īs; in fact, they may have a lot of them to offer at eBay...). I could see that the KBD scanner was common at least to the HP11C, 15C and 16C. Next? Well, I simply removed the 11Cīs KBD scanner and replaced the faulty 16Cīs for that. The 16C is working fine, thanks.
One fact that called my attention was that the 15C had 3 ICīs against the only two of the 16C ad 11C. I concluded that the 15Cīs extra IC was for the extra 64 registers. The display controller was different for each of them, so the scanner itself would in fact be the CPU, and the display driver would contain the O.S. for each model. Is it correct?
The point is that some months before that I could see and even use an HP11C that could reach more than 440 (448 max?) program lines!!! The owner told me he bought it from someone that worked at Hewlett Packard (Brazil) and it had been modified in USA. He told me, at that time, that only one IC was added.
My HP16C has space and soldering-pads for a PQPF at the same position the 15C has the extra IC. The question is: have someone did (or knows about) something like this?
If not, I am the witness of the existence of, at least, one freaky 448+ HP11C.