Hey Folks,
Finally got around to modifying my Soviet era ABM-1M (AVM-1M in english) Submariner (Podvodnik or in Russian подводник) regulator.
Contrary to what most people think, it is a two stage regulator, not a single stage. This is made clear on page 38 of the Soviet Manual of Scuba Diving. It operates as a down stream system with the Russians calling the first stage a "lever reducer" and the second stage being referred to as " valve of automatic device". The reg does have a hefty overpressure relief valve to stop damage to " reducer" and should release at 165 BAR (2393.12 PSI). The reg is rated for a max "pressure forward of the reducer" ie; tank pressure, of 150 BAR or 2175.57 PSI, so sorry, no tanks greater than 2250psi and no PLUS (+) do-dads for this baby, or you'll pop it like a cork, meaning your HP diaphragm will blow out! Gee how do I know about this little nugget of knowledge.....Hmmmm? How to adjust it you say? Fill a tank and let it cool and ensure that it has approximately 165 BAR in it and adjust your overpressure valve until it stops hissing, then tighten down another 1/8th of a turn. Check with a tank of 170 BAR and the valve should leak, then subside. Works for me, you know, tweak the leak.
No wonder I see so many pictures of this gizmo with dual tanks. The Russians appear to be using the equivalent of our 36cuf, LP dual tanks in most pictures of the AVM (ABM) in use. Since I have machinists available that do excellent turning work over here, I had an old yoke assembly modified to thread metrically to my AVM. I dive it in the pool tomorrow.