Sinclair kits oops

From: Thorhallur Ragnarsson <thorh_at_ismennt.is>
Date: Sun Aug 31 03:43:06 1997

Marvin wrote:
>
> Marvin wrote:
>
> > e.tedeschi wrote:
> >
> > > Perhaps they don't supply overseas. Try and let me know.
> > > However their kits are American and that means that the
> > > machines will NOT work in UK.
> >
> > There is no reason the kits won't work anywhere in the world as long as
> > the
> > input to the external power supply is compatible with local power. Also,
>
> Oops, I forgot about the different scanning rates for the TV's. Sorry about that!

Don?t worry about the different scanning rates - they are not all that different.
The PAL picture uses 625lines and 25frames/sec = 15625Hz line frequency,
the NTSC picture has 525lines and 30frames/sec = 15750Hz line frequency.
The ZX-81 output is Black and White only and my experience is that most B/W TV sets
and even many Colour sets will quite happily display any B/W picture without problems.
On the other hand there could be a problem with the modulator RF channel output
(UK=UHF, US=VHF) so the TUNER in a foreign TV might not receive the signal.
The main differences (PAL vs. NTSC) are how these systems handle colour
and the sound is also not compatible, there are even some regional variations
in sound transmissions within the PAL areas.

I assembled my ZX-81 kit in 1981 but unfortunately I modified (read: ruined)
it later by adding a battery backup/8KRAM of my own design when using it as
an EPROM programmer, it still works though!

I would really like to buy a new kit from Zebra Systems, but they say they
don't supply overseas - well there must be some way around that.

Best regards,

??rhallur.
Received on Sun Aug 31 1997 - 03:43:06 BST