Hello to all,
 I need to program a 16c84 part soldered to the PCB, and I've built two
homemade programmers: a "ludipipo" for the serial port and a "topic" for
the parallel port.
 None of them are able to program the pic in the circuit, but they work
fine with a "off-circuit" PIC.  I've read in this List some things to try:

   - Stop the PIC oscillator grounding the OSC1 pin.
   - Shield the cables to the PIC.
   - Cables as short as possible.

 My questions is: It's really needed to stop the PIC oscillator? What else
can I try?
 Thanks in advance.


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