GEC Genalex Fluorescent lamp - UK Vintage Radio Repair and Restoration Discussion Forum

bobhowe · 26th Jan 2016, 10:42 pm

Hi. I have this old fluorescent lamp fitting & I would say it dates from the 1950s. It takes a 65/85W T12 tube with B22d bayonet cap ends. The unusual feature on this lamp is the tube is held in the fitting by 2 sliding ends that hold the BC holders in place & there is no terry clips to hold the tube. The starter is a metal 4 pin & the PF capacitor is the size of half a tub of butter. I have 1 original new tube & thanks to the kind offer of Graham who replied in the wanted section he is sending BC to bi pin cap converters so I can use a T12 tube with bi pin ends and can keep the BC tube unused. I will post some pictures soon, regards Bob

broadgage · 27th Jan 2016, 8:18 pm

I suspect that the lamp is in fact 65/80 watts and not 65/85 watts, typo ?

4 pin starters are no longer manufactured AFAIK but you may be able to find an old one. If not, then a 2 pin starter may be used with only a minor modification.

Unlike many old fittings, your one should in fact operate a modern T8 58 watt lamp correctly provided that the ballast is 65 watt.
If an 80 watt ballast is fitted then a modern 58 watt lamp can still be used but it will be over run and have a reduced life.

bobhowe · 27th Jan 2016, 8:39 pm

Hi thanks for reply you are right the lamp is a 65/80 watt & the ballast is a 65 watt i have got a NOS bayonet ended tube that i don't want to use but i have an old phillips T12 tube with bi pin ends & i just got in the post 2 bc to bi pin converters ( thanks to Graham ) in the wanted thread . I know the 4 pin starter is u/s but i will post on the wanted section regards Bob

broadgage · 27th Jan 2016, 9:00 pm

A 65 watt switch start ballast will be fine with a modern 58 watt T8 lamp. These lamps were in fact designed as an energy saving replacement for 65 watt T12 lamps and intended to run on the same ballast.

If you can not get a 4 pin starter, then a 2 pin one may be used, either concealed within the old 4 pin starter, or elsewhere inside the fitting.

bobhowe · 27th Jan 2016, 11:42 pm

Hi managed to get a 4 pin starter kindly from forum member Ed Dinning

Hunts smoothing bomb · 29th Jan 2016, 11:10 am

Hi

If you open up the old 4 pin starter you will see that it contains a "bulb" the bimetallic strip is within this and it is exactly the same as the two pin types internally that we still use today, Disassemble a modern starter rated for 230v 4-65 watt use and take the bulb out and solder it in the place of the old dead starter bulb and reassemble and then you have a spare brand new four pin starter.

Cheers

Brigham · 29th Jan 2016, 7:28 pm

The four-pin starter may have the same sort of discharge tube as the 2-pin type. If so, it is of the later 'modified' type.
The original four-pin design had a dull filament heater to warm the bi-metal strip, in series with the tube filaments. This is what the other pair of pins is for. On the 'modified' type, these pins are strapped together.

hannahs radios · 29th Jan 2016, 9:29 pm

The original 4 pin starters were THERMAL starters no glotube in it at all just a little heater and a bit metalic strip I have fitted a glo starter in place of a thermal one and it all worked perfectly

Brigham · 30th Jan 2016, 4:43 pm

Quote:

Originally Posted by hannahs radios

I have fitted a glo starter in place of a thermal one and it all worked perfectly

...Although the behaviour of the lamp when you switch it on is a dead give-away.

broadgage · 30th Jan 2016, 9:26 pm

Yes the 4 pin thermal starters have not been made for years, they are slower to start the lamp but arguably more certain.
4 pin starters that contained a glow starter and a link between the heater connections were a later substitute and saved a little energy as they consumed nothing when the lamp was lit.
A thermal starter wasted about a watt forever.

BEWARE of 4 pin starters in a blue anodised aluminium can, especially if the original markings are not legible.
These are probably "double glow" starters and quite unsuitable for standard applications.
They consist of two electrically independent, 120 volt glow starters mounted in the same can.
These were intended for illuminated road signs that used a series pair of 8 watt or other small lamps.
It was considered that use of a single replacement "double glow" starter simplified maintenance "replace both lamps, and if they don't light, then also replace the double glow starter with a new one"
AFAIK double glow starters existed in only one rating, thereby avoiding any chance of the wrong type being fitted.

26th Jan 2016, 10:42 pm	#1
bobhowe Heptode Join Date: Jun 2005 Location: Sunderland, Tyne and Wear, UK. Posts: 661	GEC Genalex Fluorescent lamp Hi. I have this old fluorescent lamp fitting & I would say it dates from the 1950s. It takes a 65/85W T12 tube with B22d bayonet cap ends. The unusual feature on this lamp is the tube is held in the fitting by 2 sliding ends that hold the BC holders in place & there is no terry clips to hold the tube. The starter is a metal 4 pin & the PF capacitor is the size of half a tub of butter. I have 1 original new tube & thanks to the kind offer of Graham who replied in the wanted section he is sending BC to bi pin cap converters so I can use a T12 tube with bi pin ends and can keep the BC tube unused. I will post some pictures soon, regards Bob

27th Jan 2016, 8:18 pm	#2
broadgage Nonode Join Date: Jan 2010 Location: North Somerset, UK. Posts: 2,129	Re: GEC Genalex Fluorescent lamp I suspect that the lamp is in fact 65/80 watts and not 65/85 watts, typo ? 4 pin starters are no longer manufactured AFAIK but you may be able to find an old one. If not, then a 2 pin starter may be used with only a minor modification. Unlike many old fittings, your one should in fact operate a modern T8 58 watt lamp correctly provided that the ballast is 65 watt. If an 80 watt ballast is fitted then a modern 58 watt lamp can still be used but it will be over run and have a reduced life.

27th Jan 2016, 8:39 pm	#3
bobhowe Heptode Join Date: Jun 2005 Location: Sunderland, Tyne and Wear, UK. Posts: 661	Re: GEC Genalex Fluorescent lamp Hi thanks for reply you are right the lamp is a 65/80 watt & the ballast is a 65 watt i have got a NOS bayonet ended tube that i don't want to use but i have an old phillips T12 tube with bi pin ends & i just got in the post 2 bc to bi pin converters ( thanks to Graham ) in the wanted thread . I know the 4 pin starter is u/s but i will post on the wanted section regards Bob

27th Jan 2016, 9:00 pm	#4
broadgage Nonode Join Date: Jan 2010 Location: North Somerset, UK. Posts: 2,129	Re: GEC Genalex Fluorescent lamp A 65 watt switch start ballast will be fine with a modern 58 watt T8 lamp. These lamps were in fact designed as an energy saving replacement for 65 watt T12 lamps and intended to run on the same ballast. If you can not get a 4 pin starter, then a 2 pin one may be used, either concealed within the old 4 pin starter, or elsewhere inside the fitting.

27th Jan 2016, 11:42 pm	#5
bobhowe Heptode Join Date: Jun 2005 Location: Sunderland, Tyne and Wear, UK. Posts: 661	Re: GEC Genalex Fluorescent lamp Hi managed to get a 4 pin starter kindly from forum member Ed Dinning

29th Jan 2016, 11:10 am	#6
Hunts smoothing bomb Octode Join Date: Oct 2005 Location: Wimborne, Dorset, UK. Posts: 1,407	Re: GEC Genalex Fluorescent lamp Hi If you open up the old 4 pin starter you will see that it contains a "bulb" the bimetallic strip is within this and it is exactly the same as the two pin types internally that we still use today, Disassemble a modern starter rated for 230v 4-65 watt use and take the bulb out and solder it in the place of the old dead starter bulb and reassemble and then you have a spare brand new four pin starter. Cheers __________________ Lee

29th Jan 2016, 7:28 pm	#7
Brigham Octode Join Date: Mar 2006 Location: Co. Durham, UK. Posts: 1,117	Re: GEC Genalex Fluorescent lamp The four-pin starter may have the same sort of discharge tube as the 2-pin type. If so, it is of the later 'modified' type. The original four-pin design had a dull filament heater to warm the bi-metal strip, in series with the tube filaments. This is what the other pair of pins is for. On the 'modified' type, these pins are strapped together.

29th Jan 2016, 9:29 pm	#8
hannahs radios Hexode Join Date: Jan 2012 Location: Weymouth, Dorset, UK. Posts: 422	Re: GEC Genalex Fluorescent lamp The original 4 pin starters were THERMAL starters no glotube in it at all just a little heater and a bit metalic strip I have fitted a glo starter in place of a thermal one and it all worked perfectly

30th Jan 2016, 9:26 pm	#10
broadgage Nonode Join Date: Jan 2010 Location: North Somerset, UK. Posts: 2,129	Re: GEC Genalex Fluorescent lamp Yes the 4 pin thermal starters have not been made for years, they are slower to start the lamp but arguably more certain. 4 pin starters that contained a glow starter and a link between the heater connections were a later substitute and saved a little energy as they consumed nothing when the lamp was lit. A thermal starter wasted about a watt forever. BEWARE of 4 pin starters in a blue anodised aluminium can, especially if the original markings are not legible. These are probably "double glow" starters and quite unsuitable for standard applications. They consist of two electrically independent, 120 volt glow starters mounted in the same can. These were intended for illuminated road signs that used a series pair of 8 watt or other small lamps. It was considered that use of a single replacement "double glow" starter simplified maintenance "replace both lamps, and if they don't light, then also replace the double glow starter with a new one" AFAIK double glow starters existed in only one rating, thereby avoiding any chance of the wrong type being fitted.