Ack!  That's a scary thought.  I was hoping for something along the lines of 
trying both options but using some resistor on the MCLR line with enough 
resistance to prevent damage if it's the PGD pin, yet have enough oomph to 
program the PIC if correct.

Getting back into the application is a bit difficult as it involves un-gluing 
and re-gluing some trim pieces, and pulling off some clips on old plastic 
that already started breaking.  Something I'd really really like to avoid.

-Neil.


On Sunday 15 April 2007 18:37, Tamas Rudnai wrote:
> Hi Neil,
>
> I would say don't be lazy and check the pins manually, but if you really
> don't want it the 'hope and pray' technique could be the following:
>
> NOTE: I could be completely wrong on this, do not trust on me and do not
> send the bill for me of your damage if you try this out <grin>
>
> 1. run your circuit as normal
> 2. pick a pin from the possible two
> 3. feed it by 10V for 5us
> 4. see if the chip made a reset or not - if yes this should be the MCLR/Vpp
> pin, if not you might burned out the PGD pin.
>
> This is because according to the datasheet when Vpp reaches the Vihl level
> for Thld0 long it enters to programming mode and it will reset all states,
> all pin becomes input, PC will be 0 - so a reset occurs.
>
> Tamas
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