I have found the solution to my problem.

My adpator board was wired incorrect, i had connected clk to gp2 instead of
gp1 and data to gp1 instead of gp0. In few minutes with the iron all was
fix, now successfully programs the 12c508.

Thanks to the ppl who offered solutions, as i sit here very red faced. A
re-read of In-circuit programming chapter (DS40139C-page38), made every
thing click.