Homebrew PCBs

Maybe its time to pop it open- see if you can trace the serial signal
from the connector into the innards of the plotter? I doubt it has a
blown Max232 interface chip, but you might see something out of whack...

.--- In Homebrew_PCBs@yahoogroups.com, Lez <lez.briddon@...> wrote:
>
> I have got to the end of the road with this plotter.
> 
> I have made a few test cables, I have bought a rs232 dongle with LEDS
> in so I can see whats going on, and I can see the data light flash
> when I hold a key down in hyperterminal.
> 
> I have tried 3 wires, which is fine for pc, i have connected the
> handshake pins back to themselves (6,8,20) (4,5) at the plotter end.
> 
> It echos nothing back, I can drive the pen aorund with the arrow keys
> on the plotters front panel but I see nothing out the serial port,
> maybe I should, maybe I shouldnt.
> 
> I know it works as when I bought it I held down a key(or 2) and it was
> off drawing a self test on the bed without paper in, I cant do that
> now I cant remember how I did it!
> 
> But if I interrupt the travel of the pen, it stops and flashes the
> error light, so all self tests seem fine.
> 
> 
> So last thing I can think to do is to 'copy' a genuine 'cpgl' or
> 'ccgl' file to com1:
> 
> Has anyone got such a file, just to plot a square or triangle,
nothing huge etc.
> 
> -- 
> 
> Lez
>