Hi ev'rybody,

I've troubles getting a home-built Tait-style 16F84 programmer to work,
although I believe the hardware (parallel port, D0, D1 for programming, ACK
for readback) to be correct (correct voltage of _MCLR during programming,
correct Vdd and Vss, correct "0" and "1" levels at RB6 and RB7).

I use the circuit with David Taits PP.EXE, and it verifies fine in debug mode
(PPDEBUG=1, readback is o.k.), but during programming the very first word of
WALK.HEX, PP.EXE stops with "error: read 03FF, expected 0186" or something
like that. Now I'm wondering if not the programmer, but the 16F84 chip itself
is faulty?

Does anyone have a hint where I could start searching for the problem?
I already tried various settings of PPDELAY and PPSETUP, but nothing works.
Unfortunately I just have a logic probe, but no scope for testing.
How can I test the 16F84 chip to be "good" or "bad", or further verify the
programmer hardware without a scope?

Thanks for your help,
Franz