Re: Alternative Methods of Copying Apple II+ ROMs

[Roger Johnstone <rojaws@es.co.nz>]

In <npfDa.16511$49.629665@twister.socal.rr.com> Bryan Villados wrote:

> Sorry if I'm being a nuicance about this... A previous thread on the
> EUROPLUS is confusing me, which is why I started this thread. 
> Quadrajet wrote the following awhile back:
>
> "One thing different I recall about the Europlus was a few pad jumpers 
> on the motherboard to change some timing from 60 Hz to 50 Hz AC power 
> systems."
>
> Is this something I should be concerned about before attempting to 
> power up the board? I haven't received the board just yet, so I can't 
> try it right now.
>
> --- Bryan

No, you only need to worry about the input voltage the power supply will 
accept. At least some of the Europluses were sold with a power supply 
that could be switched between 110V and 220V.

For historical reasons most countries have a TV system which uses the 
same video field frequency as their AC power supply, so TVs and monitors 
in most European countries were designed for 50 hertz video, but the 
original Apple II was designed for the US 60Hz TVs. The 50Hz/60Hz pads 
in an Apple II+ are only to do with the timing for the video generation 
circuit. Changing the jumper pads allows an Apple II+ to generate 50Hz 
video, which makes it more compatible with PAL and SECAM monitors, 
although it still uses NTSC colour encoding. Even then it's not normally 
necessary since most monitors will synchronise to either a 50 or 60Hz 
video signal, although you may need to adjust the vertical hold and size.

-- 
Roger Johnstone, Invercargill, New Zealand

Apple II - FutureCop:LAPD - iMac Game Wizard
http://homepages.ihug.co.nz/~rojaws/
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