Had a small problem trying to program the 16F628A chips. Some would take the program, upload the curve and talk to the monitor program without any problems.

Others would program and verify as ok but just would not talk to the monitor program and therefore I could not load the curve.

Finally used an old "Tait Classic" programmer I have here. Schematics are still available at the same web site below.

I also used a new programming software Winpicpgm 1.5.8.0.

This will detect both the programmer and the chip type automatically and then set configuration to suit.

In the "log" area it will also tell you if a chip is ok or not. Very useful as I had one that I suspected as being dead but wasn't sure
because there was no test to prove it other than try to program. If it failed, then assume as dead. This was not the case with another 2 chips I had problems with. Turned out they were not being programmed correctly.

Winpicprm and Tait Classic programmer schematics available here .......

http://members.aon.at/electronics/pic/picpgm/index.html