On 2012-11-26, at 20:04, Gerrit Heitsch wrote: >> All of this I understand but on the same monitor (a TV studio monitor), the 8565 gives virtually _no_ artefacts. Of course the picture from 8565 is not 100% perfect either, and for the good reasons you described above but it does not disturb. Here those effects are actually quite disturbing.. > > Maybe you have a particularly 'bad' 6569 in that respect. The chip is NMOS, but gets fed the 17.73 MHz (4 x color clock) which it then uses to generate the differently phased 4.43 MHz it uses to generate the color signal. > > That's a pretty hefty job and probably the reason why the 6569 still needs +12V instead of running completly on +5V like the HMOS-II 8565. > > Maybe that generator in your 6569 is a bit 'off' with respect to signal quality? Have you tried a different 8701? After I fixed that second board I have now two working 250425s. Both behave almost identically. Swapping VICs and 8701s doesn't make any change. > Also, some people claim, that the old clock generator (74LS629 and MC4044P on the 250407 boards) produces less jitter than the 8701. I watched the clocks from the 8701. They look differently on the wide and on the narrow boards but generally both seem to have similar jitter (as far as I can tell from measuring freq on different ranges) while the output from 8565 doesn't create the ghostings. The chroma output from 6569 and 8565 does differ significantly though. Hm, maybe I check with a "regular", not studio monitor. Who knows, maybe this one is more sensitive to things being off norm. -- SD! Message was sent through the cbm-hackers mailing listReceived on 2012-11-26 20:02:05
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