Quote Originally Posted by g7jiq View Post
I never doubted her in the first place,
I just couldn't see the wood for the trees....
Out of interest Dave, did you try inverting the MCLRE config assignment ?

The only reason I suggested it may be a problem was because I had a similar problem once. Now that you mention whcih programmer you used I recall that was the same programmer I had when I had the problem. (Did you know you can upgrade the firmware of that thing to the latest version to make it cover more pics with more memory etc ? it's worth looking into.)

As for the led and the opto in series, you had a 470ohm resistor across 0.4V, which means the current limiting was in the order of I=V/R = 0.4/470 = 0.00085 A (850uA microamps)

That's not normally enough to drive anything requiring a strong switching signal, though most TTL circuits should cope.