|Re: TI-59 LED intensity|
Message #6 Posted by Vieira, Luiz C. (Brazil) on 19 Jan 2010, 7:42 p.m.,
in response to message #5 by Michael Meyer
you see, the only two TIīs I feel confident about using and repairing are the TI58C and TI59. The TI58 seems to be almost like the TI59, but the TI58C has a different circuit. The reason is simple: technology timeline and history. I almost worship these two models because they were way ahead of their time when they appeared. Their printer (PC100C) was external and could be shared amongst models (HP had the printerless HP67 OR the HP97 with built-in printer, and the affordable HP34C), they could also share the Solid State Software Library (ROM modules, available later only with the HP41) and they had plenty of memory. They were fast too, but if we inspect the diagrams (again) weīll notice that they had a 4-bit data bus (RAM TMC0589, A.L.U. TMC 0501 and C.U.'s TMC 0582/0583) that would allow many operations to be performed in less cycles. Standard and Library ROM's use a serial access (Q1, Q2 control lines) similar to the one found in the HP41. Thatīs what I like most: to inspect their 'guts' and assimilate them (am I a BORG? Should resisting be futile?)
Click to enlarge (big one, 1.2Mb)
My first calculator ever was a TI57 (still have it, still works) and I used it in the first one and a half years of the University. A fellow mate. The first TI59, along with the PC100C, was a gift from a a former colleague (retired teacher) at the university, and it worked for almost two years. The other two were bought at local e-bay (mercado livre), but none of them are working. The one in the picture (rightmost, over the pale box) is just the empty case. The TI58C (over the PC100C box) works fine, but has a problem with the memory. I was given an old unit and will try to make one fully working out of the two.
The next pictures show one of the card readers. I tried to replace the gooey roller but I could not find a fine replacement so far. All of the other components seem fine (after a 'heavy' cleanup).
Click to enlarge Click to enlarge
I cannot lie to you, doc (afterall, you are a psychologist, why should I?). I'd love to have a working TI59 as part of the 'family'. As you can see in the pictures, thereīs a lot of magnetic cards waiting for being read and listed so I can register their contents and operation. I like to 'reverse engineer' these programs and retrieve their flowchart and 'working mechanics'. My brain cells take this kind of activity as relaxing... (should I look for help?)
Well, doc, I guess that the next step is to send you an e-mail with my actual address, right? Can I use the regular e-mail from the MoHPC contact form? Is yours updated? Mine is not, so I must contact you first, if using a valid MoHPC contact e-mail.
Thank you very much. And if there is anything I can do you for, you know you can count on me the same way.
Edited: 19 Jan 2010, 7:48 p.m.