Re: Roberts RMB Problems
I can confirm that the LT heater supply on the RMB Trader sheet 1037 is incorrectly documented.
The actual circuit is a centre tapped transformer, with the centre tap returned to chassis. A selenium bridge rectifier is fitted, with the two transformer AC inputs connected to the ~ connections and the DC output taken from the +. The - output is however not connected, so the bridge only functions as a bi-phase rectifier. I think there is a small degree of adjustment to the DC voltage by selecting tapping points on a length of resistance wire on a tag strip near the rectifier.
Ron
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