GPO Key and Lamp units - UK Vintage Radio Repair and Restoration Discussion Forum

Sparks · 8th Oct 2022, 9:25 pm

Were these assembled entirely by hand or did machines of some sort get involved ?
I dismantled a 10 key unit last week and it took hours, long enough for me to cut several waxed cable ties, curse at the rigidity of the cable looms and marvel at the solder connections and tight wire wrapping on the switches and terminal boards. It all looked superhuman or the work of a robot!

mark.woodward · 15th Oct 2022, 7:38 am

I was a GPO apprentice in the early '70s, and at one stage, had to wire key-and-lamp units in a local factory office complex. The internal wiring was mainly pre-assembled but the external wiring to connect it to the office telephone network was my task - a long job, all soldered ad with few diagrams etc. The company was Benfords of Warwick - long gone now, they used to make dumpers etc.

lesmw0sec · 15th Oct 2022, 9:52 am

I don't know about this kit, but it often amazes me as to the accuracy and even beauty of some wiring I have seen - all done by those skilled in what is almost an art form. I recall a woman who produced the looms for the EMS synthi 100 - every wire exactly positioned and the correct length. I can do a passable job, but never achieved such precision! A bit like producing smooth plaster - you either have the skill or not.

Sparks · 15th Oct 2022, 11:18 am

They're a work of art. In order to adapt the unit to my own purpose I had to strip it down so I could see what goes where, what colour and so on. I've done a successful, if untidy, job but I wouldn't want to do it again. Love those switches though.

1954Fender · 15th Oct 2022, 7:06 pm

Often wiring was "preformed" on a jig which allowed the cable fan out to be completed accurately before assembly into the equipment. The individual wires were "dressed" to be straight running and of the correct length. The whole assembly was then laced with waxed lacing twine holding all the wires in the correct positions for terminations.

Where cables were run overhead in large exchanges they were often arranged in a box formation and laced together. The individual cable pairs were then run down the rack side, formed and laced. It was sometimes possible to trace the individual wire colour from the top of the rack to the bottom.

The contractors were meticulous in their workmanship. It was a work of art which usually was never seen.

8th Oct 2022, 9:25 pm	#1
Sparks Heptode Join Date: Oct 2006 Location: Leeds, West Yorkshire, UK. Posts: 596	GPO Key and Lamp units Were these assembled entirely by hand or did machines of some sort get involved ? I dismantled a 10 key unit last week and it took hours, long enough for me to cut several waxed cable ties, curse at the rigidity of the cable looms and marvel at the solder connections and tight wire wrapping on the switches and terminal boards. It all looked superhuman or the work of a robot!

15th Oct 2022, 7:38 am	#2
mark.woodward Diode Join Date: Aug 2011 Location: Royal Leamington Spa, Warwickshire, UK. Posts: 2	Re: GPO Key and Lamp units I was a GPO apprentice in the early '70s, and at one stage, had to wire key-and-lamp units in a local factory office complex. The internal wiring was mainly pre-assembled but the external wiring to connect it to the office telephone network was my task - a long job, all soldered ad with few diagrams etc. The company was Benfords of Warwick - long gone now, they used to make dumpers etc.

15th Oct 2022, 9:52 am	#3
lesmw0sec Octode Join Date: Jul 2009 Location: Carmel, Llannerchymedd, Anglesey, UK. Posts: 1,506	Re: GPO Key and Lamp units I don't know about this kit, but it often amazes me as to the accuracy and even beauty of some wiring I have seen - all done by those skilled in what is almost an art form. I recall a woman who produced the looms for the EMS synthi 100 - every wire exactly positioned and the correct length. I can do a passable job, but never achieved such precision! A bit like producing smooth plaster - you either have the skill or not.

15th Oct 2022, 11:18 am	#4
Sparks Heptode Join Date: Oct 2006 Location: Leeds, West Yorkshire, UK. Posts: 596	Re: GPO Key and Lamp units They're a work of art. In order to adapt the unit to my own purpose I had to strip it down so I could see what goes where, what colour and so on. I've done a successful, if untidy, job but I wouldn't want to do it again. Love those switches though.

15th Oct 2022, 7:06 pm	#5
1954Fender Triode Join Date: Aug 2009 Location: Devon, UK. Posts: 23	Re: GPO Key and Lamp units Often wiring was "preformed" on a jig which allowed the cable fan out to be completed accurately before assembly into the equipment. The individual wires were "dressed" to be straight running and of the correct length. The whole assembly was then laced with waxed lacing twine holding all the wires in the correct positions for terminations. Where cables were run overhead in large exchanges they were often arranged in a box formation and laced together. The individual cable pairs were then run down the rack side, formed and laced. It was sometimes possible to trace the individual wire colour from the top of the rack to the bottom. The contractors were meticulous in their workmanship. It was a work of art which usually was never seen.