At 10:18 AM 8/25/99 +0200, you wrote:
>Hi all,
>I think I'm having a real serious problem now ;)
>
>I build a programmer and a separate test board for the 16c84.
>Programming went well, but testing doesn't. The program in the Pic is the
>famous flashing led.
>
>The problem seems to be the crystal. It doesn't oscillate very well.
>
>I have been working on this problem for 2 weeks now, and I get kind of
>desperate ;(
>Please let me now if you have a probable solution!

Check the arkives.  I know I put in a looong discussion thread on this
subject.
With all the responses, ALL of the gory details were there.

Boils down to this:
        Get the values for the caps from the data book for the pic you are using
.
        Be sure you are using the right type of crystal (Parallel loaded).
        If you add a resistor in series as shown--be sure it is CARBON COMPOSITI
ON.
        Carbon comp generates the noise needed to kick the crystal into
oscillations--specially for watch crystals.
        Check your solder joints for opens, shorts, crystallization, etc.
        be sure your caps are the right value!!!

Scope probe will work on OSC out, but not on OSC IN.  Loads the line too much.

Pray.

kelly



William K. Borsum, P.E. -- OEM Dataloggers and Instrumentation Systems
<borsum@dascor.com> & <www.dascor.com>