[Coco] CoCo 3 to RBG...

gene heskett gheskett at wdtv.com
Thu Jul 21 13:40:18 EDT 2011


On Thursday, July 21, 2011 01:35:09 PM Steven Hirsch did opine:

> On Thu, 21 Jul 2011, Steve Batson wrote:
> > No kidding about this getting more confusing as we go. At first, when
> > I didn't get mine working after the first pass, I figured I probably
> > have a bad connection or didn't wire it right. And I haven't had a
> > chance to get back and double check my connections to make sure
> > everything is correct. With the other people here having issues, I
> > know it's not just me ;)
> > 
> > Seems pretty straight forward when you look at the connectors on this
> > board and the CoCo. If the CoCo is not putting out the proper
> > signals/levels for this board, then it's not standard RGB I would
> > think...but it works with the CM8 as well as a Magnavox RGB monitor,
> > so I'm suspecting it is a Standard RGB output requiring just the
> > proper cable to go to the monitor.
> 
> Did you try their alternate connection scheme?  If I interpret it
> correctly, moving the gray wire acts to place HSync on the composite
> sync input (while keeping VSync on the VSync in).  There must be some
> rationale for them suggesting that and it's worth a try.
> 
> > That said, I'm more inclined to think that the board is the issue and
> > meeting it's requirments is not as obvious as it should be...and the
> > skimpy manual doesn't help matters. My electronics background doesn't
> > include much video, so while I can follow much of what's been said in
> > this thread, I'm not in a position confirm or deny anything that's
> > been said. I am going to keep toying with my setup to see if I can
> > get it working, but I'm also anxious to see what others here find
> > out.
> 
> Well, if the alternate HSync connection does not get you going then it's
> a perhaps an indication that the board doesn't support H+V sync for
> 15.75 Khz. video.  To reiterate my experience:  I bought my board on
> eBay about a year ago and was never able to get it working with H+V
> sync.  I built the little adapter using a quad 2-input XOR chip and it
> provided a great picture.  After that was done, I asked the seller to
> contact the factory for clarification.  His response was to the effect
> that H+V sync was NOT supported on 15.75Khz. RGB video.
> 
> Let's see what Gene comes up with in his experiements before rushing to
> judgement.  I am very far from an expert on video while Gene are one.
> 
> Steve

Nicely putting me on end of the plank, thanks guys.  I sent them a msg 
asking for a link to the booklets pdf, and asking what signal polarity it 
expected on the 8 pin connectors sync inputs.  I have the 8220 version of 
this board, and it has zero mention of moving the grey wire.  Can someone 
elaborate on that while I am looking for a working 48 tpi floppy drive?


Cheers, gene
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