[Coco] Re: Help! A CoCo2 died on me!

[Fedor Steeman]

On 17/06/06, Robert Gault <robert.gault at worldnet.att.net> wrote:
>
>
> Your original message says, "... won't display any image anymore,
> neither through antenna cable, or the composite video output ...."
> If that is true, it is not the add-on circuit itself that has failed.
>
> The best way to trace the source of this problem would be with an
> oscilloscope; if you have one. Work out from the 6847 following the
> video signal.
>
> The circuit does not look too unusual and seems just to be a buffer amp
> perhaps bleeding in some color burst signal. Given the photos, I'd look
> for a short where a wire has been displaced during transport and is now
> touching something it should not.
>
>
Yes, I am affraid there is more going on here. The "MOTORON" test failed, so
that means that the CoCo is non-responsive for some reason. Maybe if I can
fix the video display it would at least show garbage. I was thinking: could
it be a short in the video circuitry that is confusing the entire system?
So, if I could locate and remove the short it may work again, unless some
components where blown up in the meantime...

I have found a CoCo hardware troubleshooting guide on the web that seems to
be the way forward:
http://homepage.ntlworld.com/kryten_droid/coco/coco_tm_s4.htm

However, I do not own an oscilloscope, although I may know someone I perhaps
could borrow one from. But wouldn't a simple volt-meter do for now?

Thanks so far,

Fedor