Hi Bruce,

I tried your Program but it gave me a compilation error I didnīt understand something like out of memory.

I tried Joes Define instead which at least showed no compilation error.

My small setup sits on a veroboard and I tried to hold all Cu-lines as short as possible and used the some capacitors etc.

99% of the time it didnīt work but some seconds the Led blinked as expected.

Tried some other 20Mhz 16F628A but they showed all the same behavior. Scope said the canned Oscillator is ok,. tried to use different resistors in line, parallel , from +5V to signal because it could have an open collector output......

In the evening I try again with a crystal. Damned!