Accelerating the PCT

[pubpc17@library.ucla.edu]

I finally had to try it.  I replaced the 16MHz oscillator on the PCT
board with a socket and experimented.  The bad news is that this clock
does not seem to regulate the processor speed.  It is tied into the
PCT's video.  When I put in a 32MHz oscillator, I got 4 mini images
of the PCT screen on the monitor (one on each corner looking like a
small version of what the entire screen supposed to look like).  I
think that this information would be useful to a Second Sight user
with a VGA monitor.  The PCT's ColorSwitch video, although it simulates
CGA, is analog.  Normally, the vertical scan frequency is 15.75kHz
(governed by the 16MHz oscillator, I gather).  Putting in the a new
oscillator of the right frequency should enable the ColorSwitch to
drive a VGA monitor with a 31kHz scan rate.

In anycase, I am convinced that the PCT is simply a Turbo XT clone on
a card and that an XT-to-286 or XT-to-386 replacement chip would work
on it.  These chips do not need a new clock, so even if the clocking
signal is coming from the slots they should still accelerate the PCT.
The problem is that while the PCT emulates an old PC, the technology
used in the board is itself pretty cool.  It looks like a multilayer
circuit board with surface-mounted components and very fine traces.
The processor is not socketed, but I do not have the skills to desolder
SMT components.  There is no way a crude pencil-type soldering iron
could work on the multiple/fine contacts, for one.

Anyone with the right skills/equipment want to try it on their PCT?
If successful, I for one would pay to have a socket installed in
place of the CPU and no doubt all the Apple II publications would be
dying (ie. PAY $$) to publish an article about the story.

I have one last question to the PCT gurus out there.  Will the PCT
recognize a parallel port Zip Drive?  I am asking because when I run
the Iomega GUEST.EXE driver program, it polls for a Zip drive (I
cannot actually test this because I own neither a Zip drive nor a
parallel card).  Does this mean that if I had a parallel card I could
run a parallel Zip drive?  What about a IIGS serial port piped through
a (bidirectional) serial<->parallel converter?  The GUEST driver sees
a parallel port if the PCT control panel is installed with the right
LPT driver.