Digitol 4 Mk III controller

[Pacific231G]

During a recent clearout of the garage I dug up a Digitol 4 Mk III Controller produced by a firm called SEC (Southern Electronic Consultants) I must have picked it up at a show aeons ago but amazingly it still works though the reversing switch which feeds directlyto the output wires is a bit uncertain but may just need a squirt of cleaner.

It's the type of controller that has a separate regulator and brake and is designed for panel mounting with 15/18 VAC in 0-12V DC out max 1.5 amps. Looking at the PCB it appears fairly simple with a bunch of resistors and diodes, half a dozen non power transistors three coils and a component on the other side of the board which looks beefy enough to be the final power stage but is fairly well hidden . Not an IC in sight but it works suprisingly well with my Bachman Lilliput 140C and it was quite good fun to actually have to drive it though there was quite a lot of buzzing so I suspect a fairly dirty waveform and some residual voltage when the regulator is shut. My guess is that the thing simply produces a rising or falling voltage and there's probably no feedback

 

I'll probably not use it as such a controller is a nightmare for shunting and I'm unlikely to build a layout with an open run any time soon but I'm curious about it so wondered if anyone knows anything more.