Re: Unusual IIc??

[Michael Mahon <mahon@cup.hp.com>]

Urs Hochstrasser wrote:
> 
> In article <tcpnntpd.16.8.21.21.50.44.3183328205.65961@lost-gonzo.com>, <sysop@Lost-Gonzo.com> writes:
> > TO>   I have 2 IIcs (both 255 versions) but one has some modification done
> > TO>to the original motherboard.
> [snip]
> 
> > i'm no expert...but perhaps it is due to the fact i think europe does
> > not use the 110v system it is 215 v or something perhaps this
> > modification has something to do with it....?
> This would probably be handled in the power supply. But in the US electric
> power and TVs have 60Hz, in Europe it's 50Hz. Circuitry has probably to
> be adapted for such a difference (especially for video). I think the 555 is a
> timing chip. In the Apple ][ keyboard encoder board, a 555 was used to
> implement the Repeat key.

Nope.  The 'repeat' function was implemented in the encoder chip.

The only '555' timers in a ][ are the four in the 558 quad timer for
the paddles/joysticks.

-- 
-michael

===============================================================
This is my personal opinion, and does not in any way represent
the position of my employer, etc...