[Coco] S-video Prospects...

[Chris Hawks]

---Reply to mail from John Kowalski about [Coco] S-video Prospects...
> 
> The reason I changed the capacitor on the clock crystal was because I just
> got a black & white display when I used the recommended capacitor value.  I
> suspect my crystal may have been a bit off and my monitor simply did not
> lock onto the NTSC colorburst frequency until I tweaked it a bit.

    Thanks! That's what I thought, but, wanted to check. I haven't used
this stuff in many years (let alone how long ago I learned it).

> None of the changes to capacitors/resistors will have an effect on the
> horizontal centering of the CoCo's display.   Did you try hooking up the
> regular video out (from the back of the CoCo3) to your monitor?  Is the
> first 1/2 character in the 80 column display still cut off?   I'd be willing
> to bet that yes, it still is.

    Yes, I hooked the composite (from the Coco 3) to the TV and no, it
doesn't cut off any charcters. But, I did notice that the composite image
had a small border (1/4 inch) on the left side, that got narrower down the
display. I check the s-video again (with my good glasses, and my wife
_not_ trying to watch TV) and it does the same but, there is no border at all.
The N in the Nitros9 sign-on is all there and the first characters gradually
disapear 'til the last few lines are missing the entire first character.
Looks like the yoke is a bit crooked.

> The problem isn't the circuit, but rather the CoCo's video generator.  They
> messed up the video's horizontal timing when they designed the GIME.  CoCo3
> users have had to suffer the first 1 or 2 characters in the 80 column screen
> getting cut off on their TV for a long, long time.
> 
> Anyway, it depends on your monitor.  My CoCo's monitor has a horizontal
> position knob and I can adjust the centering.  My TV does not, but it
> displays okay anyway.  But, my PC monitor (which also has an S-video input)
> does not let me adjust it and cuts off the first character in the 80 column
> screen.

    Sounds like it's display dependant. I'll look at adding an adjustable
delay (horizontal centering control, like all TVs used to have).

Thanks all, for your input!

---End reply

Christopher R. Hawks
HAWKSoft
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The trouble with conspiracy theories are that they assume the government 
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