Re: Problem PCT With ZipGS

[dempson@actrix.gen.nz (David Empson)]

Bryan Parkoff <BParkoff@satx.rr.com> wrote:

> Yes, I use ColorSwitch and it causes PCT to scroll and/or scramble video
> controller.  It works fine with native IIgs, but not through PCT.  I tried
> two different ColorSwitch boards.

Can you describe the video symptoms more clearly?

By "scroll" do you mean that the screen "rolls", i.e. it appears to have
lost vertical hold?  This could be caused by the PC Transporter
generating a different frame rate from your normal IIgs settings.  For
example, if you have the IIgs set to refresh the screen at 50 Hz and the
PC Transporter refreshes at 60 Hz, I would expect to see this sort of
problem.  Adjusting the vertical hold on the monitor should fix it
(though you might have to adjust it back again when returning to normal
graphics).

Despite living in a country where the mains supply frequency is 50 Hz, I
preferred to run my IIgs display at 60 Hz to reduce the visible flicker
(and so that timers based on the vertical retrace operated at the
correct speed).

I'll need a better description as far as the "scrambled video" is
concerned.

One possible explanation is that  the PC Transporter is having trouble
accessing its own video memory, or something of that nature.  You might
like to try adjusting the ZipGS settings so that the slot containing the
PC Transporter is set to operate at "slow" speed.  (This is controlled
by the switches 1 through 7 on the second bank, but I'd have to dig out
the manual to confirm the setting - my recollection is that the switch
must be in the OFF position to slow down the slot.)

-- 
David Empson
dempson@actrix.gen.nz