22 Apr
2007
22 Apr
'07
9:30 p.m.
Chuck Guzis wrote:
Nothing in the PC depends on the mains line frequency. All the outputs
I recall in 1983 how difficult it was to even
*order* a 220V 50Hz
5150 from IBM. The IBM sales office people just shrugged their
If the entire system was designed around the NTSC frequency (and one
would assume the 60Hz AC power to match) then how did a "euro" IBM PC
work? Did it have 60Hz CGA as well? from the PSU are DC, there's not even a
mains-frequency heartbeat signal.
All the timing comes from crystal oscillators
(one on the motherboard,
maybe on the expansion cards too).
A European PC with a CGA card will output 60Hz NTSC video. Europ[ean TVs
in general won't display that (wel, modern ones probably do, but 25 years
ago they didn't), but the 5153 monitor (IBM CGA monitor) doesn't depend
on mains frequency either, and will work find on 50Hz mains of the
appropriate voltage
-tony