I am in need of a manual for a Heath HW-100.

Charlie-

In case you are still looking, you might expand your search to include the
HW-101, SB-100, SB-101 and SB-102.

The main difference between these models is the VFO module. I think each is
unique. If you need information about the rest of the radio, there is very
little difference. For example, one might use dial cord to couple shafts that
rotate together, while another might use an O-Ring as a belt.

73, Fred, K4DII