MSDOS Source code leaked
julesrichardsonuk at yahoo.co.uk
Fri Oct 13 08:43:42 CDT 2006
Tony Duell wrote:
>> As a curious aside, the trimmer near the 14 MHz crystal on the 5150 is
>> intended not to adjust the time-of-day clock accuracy, but rather to adjust
>> color rendition with the CGA card.
> But only if you're using a composite NTSC monitor (the colour subcarrier
> -- 3.58-ish MHz -- is 1/4 of the master clock freqwuncy, of course). On
> a TTL RGB monitor, like the 5153, the trimemr does nothing.
That's interesting, though. IBM must have believed that the 5150 would be a
global product and I'd expect that was the plan all along - so why put
circuitry on there for one market only?
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