Wireless of the Week - week 22

[Chris Suslowicz]

Originally Posted by Jesse Browning

The sexton has a 190 control box tapped for wires that run through the vehicle conduit to the speaker at the front of the crew compartment.

Looking at the Parts Identification List (FZ256/3), the 190 is very similar to Control Unit No.3 (A or B), except that there's an extra 270 ohm resistor somewhere on the top switch, and a 3-way tag board in place of the usual 4-way one in the top box. I suspect the resistor is connected in series with the feed to the loudspeaker terminals to limit the load on the WS19 output transformers and make it look a bit more like a set of headphones. There does not appear to be a volume control anywhere in the system, nor any facility for intercom use - the loudspeaker is output only by the look of it from the component listing.

Chris.