--- Tony Duell <ard_at_p850ug1.demon.co.uk> wrote:
> > I've never seen anyone have to hook a not-VR201 to a Rainbow or
> > DECmate,
> > but I have built the reverse cable to use a VR201 with an Amiga...
>
> Actally, the former is easier, in that you don't have to worry about the
> 12V DC supply.
Right... I know it's trivial, but I guess that VR201s are so unloved
for any other purpose than I've always gotten them with my beige DEC
boxes (DECMates, 'Bows, Pros, etc.). Except for the one I knocked off
the table (ow!) I've never had one die (now I have a spare analog board)
> > It's been a topic before, but I wish there was a way to drive that
> > VR201 from my COSMAC VIP
>
> YEs, I remember this thread. IIRC, we concluded that the VIP video output
> had a rediculous DC offset on it or something.
It has a very simplistic circuit (two resistors) for merging sync and
signal. Some monitors have no problem locking on to them, the VR201
can't.
> Can it not be buffered and level-shifted?
I'm sure it can be. I only know little bits about video magic, so it's
beyond me to design a fix. I would not be adverse to building an active
buffer, but I have no idea where to start. It should be powered by
either +5VDC or +12VDC to minimize hassle when connecting the VIP to
the VR201 in the first place (one needs one voltage, the other needs
the other; why add a third voltage unless it's something like -5VDC).
As before, I'm open to suggestion. In the meantime, I picked up an RCA
brand mono monitor from those days for $5 at the Uni Surplus. I need to
get it from my living room to my test bench and try it out.
-ethan
__________________________________________________
Do You Yahoo!?
Yahoo! Sports - Coverage of the 2002 Olympic Games
http://sports.yahoo.com
Received on Tue Feb 19 2002 - 16:56:39 GMT