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Vintage Computers Any vintage computer systems, calculators, video games etc., but with an emphasis on 1980s and earlier equipment.

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Old 23rd Jun 2019, 10:35 am   #1
ViperSan
Tetrode
 
Join Date: Jun 2019
Location: Manchester, UK
Posts: 81
Default Colour from Mono Apple II Europlus

This project was done a while back ..
and I have posted this on Amibay in the past.
I thought I'd re-post it here in case anyone ever needs this solution.

I decided to try and revert my Apple II Europlus to an Apple II Plus
Basically the same unit ..but the Euro is PAL and the Plus NTSC.
Woz basically designed the Plus(NTSC) to use colour artfacting ..which sends pixels at specific times relative to the colour phase..
Call it a bodge or hack ..but it works.
In NTSC that is.
Sadly this method does not translate correctly in PAL systems ..thus ..no clour..
monochrome only.
But if an NTSC capable monitor is used and the PAL undo mods implemented in the Europlus are reversed..
voila ..
you have a PLUS unit.
The mod requires unsoldering links on the logic board ..soldering others..(I used removeable jumpers)
..and critically ..the systems crystal has to be replaced (I used a socket to keep it possible to reverse the mod easily)
The Crystal required has a frequency of 14.31818mhz and needs to be serial resonant..
These are tricky to find ..
which is why I took so long trying this.

anyway ..the result is that it works ..
You can see in one of the photos the same game output to a PAL crt monitor ..and an LCD muli system monitor which is NTSC capable.
appologies for the fuzzy photo images..
my camera is old ..and the lighting not great.

rgds
VS
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Old 23rd Jun 2019, 11:18 am   #2
ViperSan
Tetrode
 
Join Date: Jun 2019
Location: Manchester, UK
Posts: 81
Default Re: Colour from Mono Aplle II Europlus

Incidentally ..this is the same unit that had no working keyboard.
So I had to build one using key switches intended for a different computer.
Here are a selection of photos from this project.
A labour of love ..but it worked.
Perhaps one day I can find a working Keyboard ..but I very much doubt it.
rgds
VS
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