23 Jan
2002
23 Jan
'02
1:36 p.m.
I got the back off my dead 16C, but something is holding the PC
board into the front of the case. Isn't there one of Murphy's
laws that says that you never figure out how something comes
apart until you have broken it? I don't want to do that. How do
you get it apart?
The first thing you see once you get the back off is a hefty PC
board with the two chips on it.
I have a 34C, still working, except the ^ and x<>y key bubbles
are worn out. It used something called RSS (Roger's Solderless
System?) -- a plastic frame holds all the chips in place and
presses them against a flexi circuit. It worked OK for a while,
then I had to take it all apart and solder the chips to the
flexi. I tore out the strip of flexi that went to the battery
connector, replaced it with wire wrap wires, and cut a hole in
the side and installed a real power switch. Nasty job -- the
flexi didn't want to tin at all.
--
Jonathan Engdahl Rockwell Automation
Principal Research Engineer 1 Allen-Bradley Drive
Advanced Technology Mayfield Heights, OH 44124
http://users.safeaccess.com/engdahl jrengdahl(a)safeaccess.com
"The things which are seen are temporary,
but the things which are not seen are eternal." II Cor. 4:18
----- Original Message -----
From: "Tony Duell" <ard(a)p850ug1.demon.co.uk>
To: <classiccmp(a)classiccmp.org>
Sent: Wednesday, January 23, 2002 7:19 PM
Subject: Re: HP16C
>
> That's the "hexalator", right? Mine finally gave up the
ghost
from overuse.
The 'voyagers' (HP10C, 11C, 12C, 15C, 16C) went through
various hardware
versions. The earliest ones have a separate logic
module built
on a
flexible PCB clamped to the display the connects to
the
keyboard via a
zebra strip connector. Later versions put everything
on one
PCB. And the
even later versions (12C only I think -- the others
having
been
discontinued by then) put everything into one chip.
The older machines contain 2 chips. The smaller one is the
'Nut' CPU.
This is very similar to the CPU used in the HP41, for
example.
The CPU
also contains the keyboard scanning circuitry.
The larger chips is called 'R2D2' (seriously!). It stands for
'ROM/RAM/Display Driver'. It's everything else. ROM containing
the
code
to make the machine behave as a 16C (or whatever). RAM
for
user programs
and data. And the LCD driver.
FWIW, Voyagers suffer from bad connections. On the separate
logic module
versions. always clean the zebra strip before doing
anything
else. If
that doesn't help, or if it's all one one PCB,
then try
resoldering the
chips (fine surface-mount connections). I've had a
lot of dry
joint
problems in this series.
-tony