[Coco] Re: [Color Computer] composite driver for coco2?

[jdaggett at gate.net]

Steve

Is there circuitry connected to pin #13 and #14 of the MC1372?

If so then what you are getting out of Neil's circuit is double sideband amplitude 
modualted carrier at either channel 3 or 4. You are going to need to do some 
modifications to the MC1372 to generate solely composite bassband video. 

1) remove all components that is connected to pins #13 and 14.
2) from Pin#14 to pin#13 wire in a 1N4001 diode or equivalent with the anode 
end to pin #14 and cathode end to pin #13. 
3) wire in a 360 ohm resistor from pin #14 to +5 VDC
4) wire a 3.9K ohm resitor from pin #12 to + 5VDC 
5) wire in Neil's circuit. 

james


On 6 Mar 2004 at 14:40, sadolph wrote:

To:             	"Neil Morrison" <neilsmorr at hotpop.com>,
	<ColorComputer at yahoogroups.com>
From:           	"sadolph" <sadolph at magma.ca>
Date sent:      	Sat, 6 Mar 2004 14:40:21 -0500 (EST)
Copies to:      	Subject:        	[Coco] Re: [Color Computer] composite 
driver for coco2?
Send reply to:  	ColorComputer at yahoogroups.com,
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> 

> Hi Neil, yes I saw it--I built it this morning. 

> 

> Unfortunately, after trying to get it to work and doing some reading,

> my version of the COCO2 uses the MC1372 chip as the RM modulator.  I

> think the circuit on your site is for COCO1, and I suspect that there

> is a separate RF modulator in COCO1.

> 

> So, I think I have to hack the actual 1372 circuit to make it not act

> as a combination (composite video+modulator) and make it act as simply

> composite video.

> 

> I'm hoping someone else has gone through this in the past and has some

> tips!

> 

> thanks, Steve

> 

> 

> 

> On Mar 6 , "Neil Morrison" <neilsmorr at hotpop.com> wrote:

> > 

> > 

> > Did you look on my website?

> > 

> > <a

> > href='http://coco_docs.tripod.com/id53.htm'>http://coco_docs.tripod.

> > com/id53.htm</a>

> > 

> > It only needs +5V

> > 

> > Neil

> > 

> > ----- Original Message ----- 

> > From: sadolph

> > 

> > All,

> > 

> > I've been trying to track down a composite monitor driver circuit

> > for coco2.  I've found some circuits, but they appear to be for

> > coco1.

> > 

> > I'm wondering if anyone knows of a good circuit for coco2 color

> > composite video?

> > 

> > Thanks, Steve

> > 

> > 

> > 

> > Brought to you by the 6809, the 6803 and their cousins! 

> > Yahoo! Groups Links

> > 

> href='http://groups.yahoo.com/group/ColorComputer/'>http://groups.yaho

> o.com/group/ColorCo mputer/</a> > > >  > > 

> 

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