On 05/20/2014 11:22 AM, Jules Richardson wrote:
  Does the motherboard seem to be physically OK? Watch
out for battery
 corrosion on the PCB. 
A really idiotic suggestion, but I had it happen to me.  Make sure that
the BIOS PROMs are in the proper sockets and in the proper orientation.
A 286 motherboard that I received had not only the wrong EPROM in the
sockets, but they were reversed in each socket.  Needless to say, they
were toast.
--Chuck