31 May
2006
31 May
'06
3:55 p.m.
On 5/31/06, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
Yes, that's one of the odd ones (I have the schematic for the 1520
somewhere). Another odd one is the printer for the PC1500 handheld, it's
just an I/O chip that sits on the PC1500 processor bus, and some drivers.
Firmware running on the PC1500's processor drives the plotter.
There was also a standard controller IC (it was a
mask-programmed
microcontroller, I forget which one, but it was something standard --
maybe 6805-like), which was used in some of the desktop printers. It had
Centronics and 600 baud serial inputs.
The controller in the C= 1520 is a 6500-family masked-programmed
controller and only implemented the C= IEC bus, not serial or
Centronics. I've contemplated what it would take to make a
"negative gear" in some
durable material like aluminum and experiment with extrusion molding
Yes, I've wondered about that too. Maybe EDM would be the way to make it
(but I've not tried).
of a "slug" which would then be cut down to
the right length. Since I
have a few bare Alps mechanisms, I've also contemplated experimentally
turning down the motor shafts if I were to ever find a matching gear
that was the right size except for shaft diameter. Anyone else here
have any ideas on how to solve the perpetual cracked gear dilemma?
I am wondering aobut making lantern pinions the right size. Yes, the
tooth profile on the meshing gear in the plotter would be wrong, but
would it matter? And a lantern pinion is a lot easier to make than the
original type.
-tony