Quote:
Originally Posted by Jesse Browning
I could email you a better picture of the wiring diagram. The speaker I have only has two terminals. The only WWII picture I have of a speaker in a sexton shows only two terminals. I wonder if that would exclude its use with the radio?
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No, if the Sexton has only two terminals, then it's only for use with the WS19 (I think).
Control Unit 190 is a bit complicated (well, they all got bit complicated when the rebroadcast facility was added), but I'm getting there.
The top (3 terminal) tagstrip is for Driver Intercom, and has Speech, Mic+ and Ground.
The next tagstrip (2 terminal) is for the loudspeaker connection.
The switch has 3 wafers with 3 sets of contacts on each; from left to right (as shown on the wiring plate):
1) Loudspeaker Return - connected to ground in all positions.
2) Loudspeaker Feed - selects source via 5, 7 & 8
3) not used
4) Feeds set audio into the intercom amplifier via a resistor (this is probably the 5,600 ohm resistor, because the contacts are connected to the A and B set Tel+ output (i.e. phones) and the wiper goes via the resistor to the intercom Mic+ connection).
5) 'A' set feed if rebroadcast selection set to A&B when on IC (I think).
6) not used
7) 'B' set set feed if rebroadcast selection set to A&B when on IC (I think).
8) Set selection to Speech (intercom output) line. Centre position shorts out a resistor - this will be the low value (270 ohm) one, I think, to compensate for the loudspeaker being disconnected.
9) 'A' set unattended line - connects this to ground if the loudspeaker is switched to 'B', so that the red lamp will light if the operator's droplead is also switched to 'B', indicating that nobody is monitoring the 'A' set output.
I think that's how it all works!
Chris.