Bell and Howell projectro 1928 - UK Vintage Radio Repair and Restoration Discussion Forum

Malcolm G6ANZ · 27th Dec 2018, 4:42 pm

I have been entrusted with a projector to repair and make safe. It is a bell and Howell from about 1928. (photo projector) Being American in origin it runs from 110v this is provided from an autotransformer and goes to the projector via a 4 pin Jones plug and a 2 pin socket on the projector.(photo 110v skt and input plug) I have run up the autotransformer and it all works correctly. However I am in need of the plug and socket to complete the cabling to the projector. Does anyone have such a connector available?
Secondly, I have powered the projector, without the lamp, via a variac and the mechanics function correctly in that it will pull a film through and rewind. What I am not sure about is the on/off switch on the top next to the voltmeter. (photo top of projector) Underneath the lever are a lot of springs their purpose is unclear. (photo top of lamp housing) Also the centre of the switch goes to the live input and the bare tinned wire is at 110v. It looks as though something failed in the switch area and it was bypassed, badly.
Does anyone know how the switch is meant to operate and what the springs are for?
I have tried tracing the wiring but this is difficult as all the wires are in the same colour and they are threaded through the casing and assemblies with no slack.
Thanks in anticipation

Malcolm

TonyDuell · 27th Dec 2018, 5:34 pm

My first thought is that the 'springs' are actually resistors and that those together with the switch form a rheostat to control the lamp voltage.

cmjones01 · 27th Dec 2018, 5:55 pm

That 2-pin connector on the projector looks like it might be a NEMA 2-15P which would fit a NEMA 6-15R socket, though those are supposed to be for 250V use. There's a diagram of

https://www.seldirect.com/NEMA%20Plug.html

It's worth measuring the pins to be sure.

Chris

emeritus · 27th Dec 2018, 6:15 pm

I believe that what the UK calls a "free socket" used to be called a "connector" in the US: that is the terminology used in the 1993 McMaster-Carr catalogue, but now they just call them sockets.

The plug looks like Hubbell's original design for 110V with "tandem" pins, but includes both his original side nick detents and the later through hole version currently used.

cmjones01 · 27th Dec 2018, 6:17 pm

I knew I'd seen that plug somewhere before. Look at this page:

https://www.plugsocketmuseum.nl/NorthAm3.html

The photograph under section 2 shows the same plug. Searching around for early 'Hubbell' connectors might find something.

Chris

27th Dec 2018, 4:42 pm	#1
Malcolm G6ANZ Octode Join Date: Feb 2006 Location: Bristol, UK. Posts: 1,042	Bell and Howell projectro 1928 I have been entrusted with a projector to repair and make safe. It is a bell and Howell from about 1928. (photo projector) Being American in origin it runs from 110v this is provided from an autotransformer and goes to the projector via a 4 pin Jones plug and a 2 pin socket on the projector.(photo 110v skt and input plug) I have run up the autotransformer and it all works correctly. However I am in need of the plug and socket to complete the cabling to the projector. Does anyone have such a connector available? Secondly, I have powered the projector, without the lamp, via a variac and the mechanics function correctly in that it will pull a film through and rewind. What I am not sure about is the on/off switch on the top next to the voltmeter. (photo top of projector) Underneath the lever are a lot of springs their purpose is unclear. (photo top of lamp housing) Also the centre of the switch goes to the live input and the bare tinned wire is at 110v. It looks as though something failed in the switch area and it was bypassed, badly. Does anyone know how the switch is meant to operate and what the springs are for? I have tried tracing the wiring but this is difficult as all the wires are in the same colour and they are threaded through the casing and assemblies with no slack. Thanks in anticipation Malcolm Attached Thumbnails

27th Dec 2018, 5:34 pm	#2
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,215	Re: Bell and Howell projectro 1928 My first thought is that the 'springs' are actually resistors and that those together with the switch form a rheostat to control the lamp voltage.

27th Dec 2018, 5:55 pm	#3
cmjones01 Nonode Join Date: Oct 2008 Location: Warsaw, Poland and Cambridge, UK Posts: 2,679	Re: Bell and Howell projectro 1928 That 2-pin connector on the projector looks like it might be a NEMA 2-15P which would fit a NEMA 6-15R socket, though those are supposed to be for 250V use. There's a diagram of https://www.seldirect.com/NEMA%20Plug.html It's worth measuring the pins to be sure. Chris __________________ What's going on in the workshop? http://martin-jones.com/

27th Dec 2018, 6:15 pm	#4
emeritus Dekatron Join Date: Jan 2012 Location: Brentwood, Essex, UK. Posts: 5,346	Re: Bell and Howell projectro 1928 I believe that what the UK calls a "free socket" used to be called a "connector" in the US: that is the terminology used in the 1993 McMaster-Carr catalogue, but now they just call them sockets. The plug looks like Hubbell's original design for 110V with "tandem" pins, but includes both his original side nick detents and the later through hole version currently used. Last edited by emeritus; 27th Dec 2018 at 6:22 pm.

27th Dec 2018, 6:17 pm	#5
cmjones01 Nonode Join Date: Oct 2008 Location: Warsaw, Poland and Cambridge, UK Posts: 2,679	Re: Bell and Howell projectro 1928 I knew I'd seen that plug somewhere before. Look at this page: https://www.plugsocketmuseum.nl/NorthAm3.html The photograph under section 2 shows the same plug. Searching around for early 'Hubbell' connectors might find something. Chris __________________ What's going on in the workshop? http://martin-jones.com/