That converter looks like the one in my 1979 B1700RGH. Mine is a Powertron RM 300D
, also from Winnipeg. Unfortunately, it is the only original major component for which I did not receive a manual. My comments are based on my experience with my converter, which was gained without the benefit of any documentation.
I agree with Darwin that there seems to be something missing
. From right to left in your photo, Ralph, I see the transformer, a space where my unit has a rectifier
, the relay to switch between converter and battery
power to the 12V circuits, and the circuit breakers.
My unit does not have a full bridge rectifier, which uses 4 diodes to convert AC power to DC; instead, there are two outputs from the transformer, with each one going through a diode so only the desired polarity of power is delivered. The two diodes are mounted on a large finned aluminum heat sink. Here's a photo - although it is from a different angle it looks like a match. Please note that I took this while replacing circuit breakers, so they are just hanging on their wires, not inserted as normal through the vertical series of mounting holes down the right (left in this view from the back) side of the front panel. Also note that the transformer output wires are soldered to the diodes, while Ralph's wires from his transformer appeared to have soldered; also, the other rectifier connections use eyelet terminals, like the other non-connected wires in Ralph's unit.
The way mine is wired, if there is no AC power then the relay is in the position which connects the battery
to the interior circuits, so a missing rectifier would not cause the loss of DC power to interior lights
. I would check what is connected to the relay, and where that red wire might go (I'm guess the non-connected black ones are the negative side of the DC supply, like my grey wires, and the red is the positive output from the rectifier, but that would need to be confirmed). There was one point on my last trip during which it seemed that the relay failed to switch to battery
, but I could not reproduce the problem, and upon examination the relay always springs back to battery power.
: I realized that the relay
comments may not be clear given the original angle of view, so here's a view from the other end, showing the relay.
The grey wires on one corner of the relay are attached to the common terminal, and deliver power to the circuit breakers. The common terminal is connected to the arm which is pulled by the coil (blue cylinder) when the converter is on. Pulling the arm disconnects it from the battery contact at the bottom centre of the relay, and connects it instead to the converter output contact. So in conventional electrical terms, the battery contact is the NC (normally closed) contact and the converter output is the NO (normally open) contact. As long as the wiring is intact, when I follow the wire from the battery positive it goes to the NC terminal of the relay, through the relay to the common terminal, then on to the circuit breakers; this path is complete whenever there is no AC power to the converter, and thus none to the relay coil.