Extend the testing to include trying some other chips in your programmer. That will give some additional data points.

Also check a few things as well....these may seem so obvious but are often missed points.

- Make sure you are placing the chip in the programmer socket in the correct orientation.

- Many universal programmers have large ZIF sockets with more pin holes than many of the chips that may be placed in the socket. Make sure you know the proper way, i.e. offsetted toward the top or the bottom of the socket as appropriate to your unit.

- Carefully check your MCU device for bent or broken pins. If the chip was one unsoldered from a board make sure that all the pins are clean and not covered with flux or other contaminates.

- Check the operation of the programmer socket to make sure that when you close it that it makes contact with every pin on your MCU.

- If a special socket adapter is in use to permit your IC package type to be fitted to the programmer make sure that you do not have bent or broken pins on the adapter.

- Make sure you are using the RIGHT socket adapter. Even for the same package type adaptation not all adapters are created equal. Particularly MCU adapters.

Michael Karas