Wireless Set 19 Control Unit 190
 

As title, does anyone have a circuit diagram for the Control Unit 190?

This was used on the Sexton 25pdr SP to feed a loudspeaker, and the component values are in EMER Tels. FZ256/3, but I can't find a circuit diagram for it anywhere. :giveup

(I don't have one them to poke around inside, this is just to try and help Robert out.)

Chris.

It might be a long shot, Chris, but it might be worth asking Bovington if any of their documentation on the Sexton has the information you are looking for regarding the Tannoy installation.

David

Wireless for the warrior
 

Chris have you looked at Louis Mulstee's 'Wireless For The Warrior' books ?

I'm sure there are circuit diagrams for many of the control boxes in there.

Cheers

Phill

I have FZ256/3 and some other stuff, but nothing with the circuit diagram... nor do i have Control Box 190.

Sorry

Tim

I'm fairly sure the 190 was a Canadian 'special', as they also seem to have had the Tannoy gun control loudspeakers with four terminals - two marked "Line" and the other two "WS19".

My guess is that the WS19 pair go to different taps on the 100 volt line matching transformer (used for Apparatus Loudspeaking) and provide a headset-equivalent impedance that won't overload the set output transformer, but there's always a chance that the C.U.190 uses the IC amplifer to boost the output (and that the extra resistors around the top switch are to provide a two position volume control).

It may in any case provide far too much output to be used as a monitor speaker. :D

Best regards,
Chris.

Here is a lead Chris . Instructions inside the lid of the speakers .

Interesting...

That explains why I've never seen one of those loudspeakers with the four terminals - Canadian only. (Likewise the C.U.190.)

It's also going to be Far Too LOUD for your intended application: the intercom amplifier is a 6V6 and designed to drive up to 7 headsets (possibly more), and matching the impedance for full output is what you would want for a 25 pdr crew listening to fire orders.

Likewise, it will be too much load for the poor old 'A' set output stage (a 6B8 driving a transformer that's a fraction of the size of the one in the Tannoy speaker).

I think you will need some fixed resistance (probably around 70 - 100 ohms though that's guesswork at the moment), and a variable one (as volume control) in series with the "WS19" terminals, and connect it to a droplead or direct to one of the terminal strips in a control unit.

Which control unit(s) are you using with your set?

Best regards,
Chris.

A : No 3 MkII , standard fare .