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-   -   anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit (https://www.diybanter.com/uk-diy/76-anyone-know-how-diagnose-faulty-choke-ballast-fluorescent-light-circuit.html)

nick July 4th 03 12:15 PM

anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit
 
Hi all

I'm hoping somebody knows more about this than I do.

We have a standard fluorescent light that has stopped working.
I have replaced the tube and starter with known working ones and
still light doesnt work.

With the light switch on, I measured 240 volts going into the Choke,
but zero volts coming out of the choke.

From this I assumed the Choke was faulty (is this a correct
assumption)
Also I took out the Choke and no current passes through it using an
Ohmmeter/
Multimeter connected across the 2 terminals.
Again I figured the Choke must be faulty / open circuit from this (is
this
correct?)

I then replaced the 40W Choke with a similar thing from an old fitting
called a Ballast hoping this would fix the light.
It didnt - although for some unknown reason the light did come on for
about 5 minutes then died after putting the outer light casing back on
for the night????
Now when I switch on, there is a very dim light just at both ends of
the tube.

By the way the ballast I put in is 65W (is this important when the old
unit
was a 40W choke. The light tubes are 40W.)

I am still left wondering if the Choke is faulty, and if it is then
why isnt
the replacement ballast not working. (Yes I did connect it up the same
way)

Thanks for any help and advice
(Im surprised this isnt more of a common problem - I couldnt find
anyone
experiencing this same problem)

Regards
Nick

Frisket July 4th 03 04:18 PM

anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit
 

"nick" wrote in message
om...
Hi all

I'm hoping somebody knows more about this than I do.

We have a standard fluorescent light that has stopped working.
I have replaced the tube and starter with known working ones and
still light doesnt work.

With the light switch on, I measured 240 volts going into the Choke,
but zero volts coming out of the choke.

From this I assumed the Choke was faulty (is this a correct
assumption)


Very likely.


I then replaced the 40W Choke with a similar thing from an old fitting
called a Ballast hoping this would fix the light.


Same thing, different name

It didnt - although for some unknown reason the light did come on for
about 5 minutes then died after putting the outer light casing back on
for the night????
Now when I switch on, there is a very dim light just at both ends of
the tube.

By the way the ballast I put in is 65W (is this important when the old
unit
was a 40W choke. The light tubes are 40W.)



I am still left wondering if the Choke is faulty, and if it is then
why isnt
the replacement ballast not working. (Yes I did connect it up the same
way)

I think the old choke has probably bitten the dust. Someone else is
doubtless an expert on these things but I always try to replace like for
like when swapping components - 65w is considerably more than 40w - maybe
the 1st firing killed your starter.

Thanks for any help and advice
(Im surprised this isnt more of a common problem - I couldnt find
anyone
experiencing this same problem)

Regards
Nick




BigWallop July 4th 03 04:25 PM

anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit
 

"nick" wrote in message
om...
Hi all

I'm hoping somebody knows more about this than I do.

We have a standard fluorescent light that has stopped working.
I have replaced the tube and starter with known working ones and
still light doesnt work.


Stop there. If you've replaced both the tube and starter lamp and it still
ain't working, then the fitting itself is at fault and needs replaced. You
don't have to go any further with more tests and the like. You need a new
fitting.


With the light switch on, I measured 240 volts going into the Choke,
but zero volts coming out of the choke.

From this I assumed the Choke was faulty (is this a correct
assumption)
Also I took out the Choke and no current passes through it using an
Ohmmeter/
Multimeter connected across the 2 terminals.
Again I figured the Choke must be faulty / open circuit from this (is
this
correct?)

I then replaced the 40W Choke with a similar thing from an old fitting
called a Ballast hoping this would fix the light.
It didnt - although for some unknown reason the light did come on for
about 5 minutes then died after putting the outer light casing back on
for the night????
Now when I switch on, there is a very dim light just at both ends of
the tube.

By the way the ballast I put in is 65W (is this important when the old
unit
was a 40W choke. The light tubes are 40W.)

I am still left wondering if the Choke is faulty, and if it is then
why isnt
the replacement ballast not working. (Yes I did connect it up the same
way)

Thanks for any help and advice
(Im surprised this isnt more of a common problem - I couldnt find
anyone
experiencing this same problem)

Regards
Nick



---
BigWallop

http://basecuritysystems.no-ip.com

Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
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impvan July 4th 03 09:46 PM

anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit
 
Yes, the choke's knackered.

You haven't come across anyone else with the problem as chokes don't
often fail like this. They normally develop shorted turns and melt,
then go bang.

Chris Oates July 4th 03 10:23 PM

anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit
 

"impvan" wrote in message
m...
Yes, the choke's knackered.

You haven't come across anyone else with the problem as chokes don't
often fail like this. They normally develop shorted turns and melt,
then go bang.


and stink like hell



Terry July 5th 03 12:39 AM

anyone know how to diagnose a faulty Choke / Ballast in fluorescentlight circuit
 
Chris Oates wrote:

"impvan" wrote in message
m...
Yes, the choke's knackered.

You haven't come across anyone else with the problem as chokes don't
often fail like this. They normally develop shorted turns and melt,
then go bang.


and stink like hell


Not sure if this would apply to your 230 volt versions but I have
usually found that a faulty "ballast/transformer" (as we call our
115 volt and various other voltage versions) will have an open
primary/mains input winding. However ours, unless they are very
old like 40 to 50 years, do not use 'starters'.
ballasts for the last 40 or so years have incorporated a thermal
cut out in case the ballasts overheats and AFIK it does not reset
thus protecting against shorts and potential fires. And yes, some
of them do ooze black 'goo'. Which these days is said to be not
of the 'cancer causing' variety. i.e. PCBs!
Some appliances do use just a series choke in a very simple
inductive circuit to fire the fluorescent tube/s.
Idea anyway.

Chris Oates July 5th 03 02:02 AM

anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit
 

"Terry" wrote in message
...
Not sure if this would apply to your 230 volt versions but I have
usually found that a faulty "ballast/transformer" (as we call our
115 volt and various other voltage versions) will have an open
primary/mains input winding. However ours, unless they are very
old like 40 to 50 years, do not use 'starters'.
ballasts for the last 40 or so years have incorporated a thermal
cut out in case the ballasts overheats and AFIK it does not reset
thus protecting against shorts and potential fires. And yes, some
of them do ooze black 'goo'. Which these days is said to be not
of the 'cancer causing' variety. i.e. PCBs!
Some appliances do use just a series choke in a very simple
inductive circuit to fire the fluorescent tube/s.
Idea anyway.


series choke here, no thermal protection
not suitable as raceway even though they
are used that way.



BigWallop July 5th 03 05:43 AM

anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit
 

"Chris Oates" wrote in message
...

"impvan" wrote in message
m...
Yes, the choke's knackered.

You haven't come across anyone else with the problem as chokes don't
often fail like this. They normally develop shorted turns and melt,
then go bang.


and stink like hell



You better believe it.


---
BigWallop

http://basecuritysystems.no-ip.com

Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.495 / Virus Database: 294 - Release Date: 30/06/03



The Natural Philosopher July 5th 03 08:51 AM

anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit
 
Terry wrote:

Chris Oates wrote:

"impvan" wrote in message
. com...

Yes, the choke's knackered.

You haven't come across anyone else with the problem as chokes don't
often fail like this. They normally develop shorted turns and melt,
then go bang.

and stink like hell


Not sure if this would apply to your 230 volt versions



No, it doesn't. We have enough strike voltage without needing a step-up
transformer.

but I have
usually found that a faulty "ballast/transformer" (as we call our
115 volt and various other voltage versions) will have an open
primary/mains input winding. However ours, unless they are very
old like 40 to 50 years, do not use 'starters'.
ballasts for the last 40 or so years have incorporated a thermal
cut out in case the ballasts overheats and AFIK it does not reset
thus protecting against shorts and potential fires. And yes, some
of them do ooze black 'goo'. Which these days is said to be not
of the 'cancer causing' variety. i.e. PCBs!
Some appliances do use just a series choke in a very simple
inductive circuit to fire the fluorescent tube/s.
Idea anyway.




Dave Plowman July 5th 03 10:07 AM

anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit
 
In article ,
BigWallop wrote:
We have a standard fluorescent light that has stopped working.
I have replaced the tube and starter with known working ones and
still light doesnt work.


Stop there. If you've replaced both the tube and starter lamp and it
still ain't working, then the fitting itself is at fault and needs
replaced. You don't have to go any further with more tests and the
like. You need a new fitting.


Hmm. It might be one of several, and or no longer available. What's wrong
with fixing it?

I've put electronic ballasts in old fittings before now to retain the
appearance.

--
*Go the extra mile. It makes your boss look like an incompetent slacker *

Dave Plowman London SW 12
RIP Acorn

nick July 5th 03 12:39 PM

anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit
 
Thanks for the advice

Seems that it is the choke then (still not sure why the
replacement 65W ballast didnt work though - unless thats busted
aswell)

I will find out how much a replacement choke costs before probably buying
a complete new fitting.

Much Obliged
Nick

Dave Plowman July 5th 03 01:46 PM

anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit
 
In article ,
nick wrote:
I will find out how much a replacement choke costs before probably buying
a complete new fitting.


A 40w choke costs 3.85 + vat from TLC.

--
*If tennis elbow is painful, imagine suffering with tennis balls *

Dave Plowman London SW 12
RIP Acorn

Dave Plowman July 5th 03 07:36 PM

anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit
 
In article ,
N. Thornton wrote:
Choke = ballast.


Not really. A ballast refers to an 'all in one' control unit. A choke is
simply an inductor.

--
*If all is not lost, where the hell is it?

Dave Plowman London SW 12
RIP Acorn

N. Thornton July 6th 03 02:39 PM

anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit
 
(nick) wrote in message om...
Funnily enough the tube still works in another light fitting.

Mind you it did seem a bit like a Close Encounter of the 3rd Kind
when the light came on first time! Talk about bright - Wont need to
go to Spain this year to get sunburn.

£4 for a new choke is cheaper than I expected, but if there are
wiring faults in the starter connection aswell and the fault isnt
obvious getting a new fitting has to be the best thing to do.

Much obliged again
Nick


Why not turn the fitting into a 65w arc light? :)

Regards, NT

Andrew July 7th 03 02:01 PM

anyone know how to diagnose a faulty Choke / Ballast in fluorescent light circuit
 
(nick) wrote in message om...
Funnily enough the tube still works in another light fitting.

Mind you it did seem a bit like a Close Encounter of the 3rd Kind
when the light came on first time! Talk about bright - Wont need to
go to Spain this year to get sunburn.

£4 for a new choke is cheaper than I expected, but if there are
wiring faults in the starter connection aswell and the fault isnt
obvious getting a new fitting has to be the best thing to do.

Much obliged again
Nick


Sounds from discussion that it's a simple non-electronic fitting in
which case the wiring is sooo simple.

To fault find try wiring an ordinary light switch across the starter
connections (remove the starter) - but only if you can do it safely.
Ensure the temporary switch is open, switch on the main light switch,
close the temporary switch for a couple of seconds and open it again.
If the tube doesn't strike (light) after a few attempts then there's
another fault beside the starter.

Andrew


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