I stumbled across the BryantRV site that has service manuals for various
heaters, refrigerators, and A/C's
It includes Dometic, Norcold, Duotherm, Suburban, Hydroflame, and Carrier.
--Service documents index
---for the vintage Dometics including: MC 16, M27, M28, MA35, MA 40, M 50, M 52,MB 52, and M 70