Re: RGB card for IIe

["Bryan Parkoff" <nospam@nospam.com>]

"David Wilson" <david@uow.edu.au> wrote in message 
news:43154c45$1@news.uow.edu.au...
> Knut Roll-Lund <kr-lund@nogarbage.online.no> writes:
>>I'm considering to buy an RGB/80-columns card for my IIe.
>
>>Will a card from USA would work for me in my European Apple IIe?
>
>>I think of the frequencies... My IIe is for 50Hz power and outputs a
>>50Hz signal for video. Americans use 60Hz for power and video. So would
>>an RGB card from US output 60Hz video in my machine which would be
>>incompatible with a European monitor?
>
>>If this is a problem, would it be possible to modify the card to 50Hz
>>(by changing a crystal or something like that)?
>
> The IOU chip in the IIe is responsible for the 50/60Hz video (there are
> two different versions of this chip for the IIe with the 50Hz version 
> adding
> another 50 black lines at the end of the screen). The main crystal is also
> slightly different (14.318 vs 14.25 MHz).
>
> The RGB card will just use whatever frequency the motherboard scans the 
> RAM
> at. I have a PAL IIe with a 60Hz IOU chip because I have a Sequential 
> Systems
> Meg80z card which could not handle the different refresh pattern and would
> not display the first 7 pixels in DHR or 80 column modes.
>
> You are unlikely to have the same problem - I would buy it and try it.
    I suggest that you use RGB monitor with 60Hz and motherboard with 60Hz 
and 14.318MHz crystal chip.  You will need a converter box from 240 volts to 
120 volts so you will be satisfied.
    I have one power supply with 120 volts/240 volts switch.  I connected 
power supply to the dryer machine's electrical output which it handles only 
240volts while my house uses 120 volts.  It works very well.

Bryan Parkoff