Put up two sets of these a couple of years ago. One set is now behaving
oddly. They're both operated from the same switch, but I'm not exactly
sure how they're wired together, I didn't do that bit.

They're 12v systems with a transformer integral to the mounting point on
the ceiling for the track - so not recessed at all. 4x35w halogen
lights on the track, one transformer per track.

A couple of weeks ago, one set didn't come on. From past experience I
know if a single halogen blows, the others remain lit, but started
replacing them one by one anyway. First one I swapped, it all lit up
when I tried it again, so I swapped the 'old' bulb back in, still
worked, so I figured maybe it had worked loose from the heat or something.

Then a few days back I noticed in the periphery of my vision that the
lights (again, just this one set) seemed to be intermittently going
brighter. I've seen this sometimes when the supply's been a bit ropey,
but nothing else was affected. It cleared up, and I thought no more of it.

Tonight, having had the lights on a couple of times today, I discover
the entire set is out again. Having changed the bulbs one by one it's
still not working, and I'm none the wiser.

Having left it off and tried again, it's still dead. I'm not taking the
cover off till I can see what I'm doing tomorrow when the sun makes an
appearance again, but would appreciate some ideas on what I can look for
and try.

I have a multimeter and have a vague idea on how to use it, though most
of my experience has been on much lower voltage stuff, not mains, which
is another reason why I'm leaving it till tomorrow, so I can see exactly
what I'm about to electrocute myself with :-)

Anyone else had this, I'm assuming it must be something to do with the
transformer, but a bit puzzled why changing the bulb last time seemed to
kick it back into life. I've checked all the track is secure and tight etc.

TIA,

Velvet

Velvet wrote on Monday (09/02/2004) :
Put up two sets of these a couple of years ago. One set is now behaving
oddly. They're both operated from the same switch, but I'm not exactly sure
how they're wired together, I didn't do that bit.

They're 12v systems with a transformer integral to the mounting point on the
ceiling for the track - so not recessed at all. 4x35w halogen lights on the
track, one transformer per track.

Many of these LV units suffer the same problem, high current causing
burnt and poor connections.

As the voltage goes down, the quantity of current has to rise to make
up for it to achieve the same wattage. If all lights are out on a
track, then look at the connections between the "transformer" and the
track. If it unplugs from the track check for signs of burning and
blackening.

Less likely, but still worth checking are the mains connections to the
"transformer".

Failing either of the above, there could be a problem inside the
"transformer".

--

Regards,
Harry (M1BYT) (Lap)
http://www.ukradioamateur.org

Harry Bloomfield wrote:

Velvet wrote on Monday (09/02/2004) :

Put up two sets of these a couple of years ago. One set is now
behaving oddly. They're both operated from the same switch, but I'm
not exactly sure how they're wired together, I didn't do that bit.

They're 12v systems with a transformer integral to the mounting point
on the ceiling for the track - so not recessed at all. 4x35w halogen
lights on the track, one transformer per track.


Many of these LV units suffer the same problem, high current causing
burnt and poor connections.

As the voltage goes down, the quantity of current has to rise to make up
for it to achieve the same wattage. If all lights are out on a track,
then look at the connections between the "transformer" and the track. If
it unplugs from the track check for signs of burning and blackening.

Less likely, but still worth checking are the mains connections to the
"transformer".

Failing either of the above, there could be a problem inside the
"transformer".

Thanks, I was going to give it a quick visual for that sort of thing.
There's no evidence between transformer and track - it's the sort where
the track is a pair of rigid metal poles, with a screw clamping them
into place against each of a drop-pole. Hard to describe - they slot in
between two fingers, which have a fairly wide screw-thread on the inside
surfaces, and the big screw thus screws up from the bottom to apply
pressure both between itself and the track, and between track and upper
surface of mount.

Would something along the lines of what you describe cause the
intermittent brightening of them though? like an irregular pulse of
brightness then dropping back to normal again (or alternatively a pulse
back to proper brightness then dropping back to slightly dim). It's
very hard to see, not very noticeable at all, but my vision is very
sensitive to changes in light levels around the periphery (part of the
reason why I now have these instead of the ghastly flourescent that used
to be up there).

Velvet

"Velvet" wrote in message
...
Put up two sets of these a couple of years ago. One set is now behaving
oddly. They're both operated from the same switch, but I'm not exactly
sure how they're wired together, I didn't do that bit.

They're 12v systems with a transformer integral to the mounting point on
the ceiling for the track - so not recessed at all. 4x35w halogen
lights on the track, one transformer per track.

A couple of weeks ago, one set didn't come on. From past experience I
know if a single halogen blows, the others remain lit, but started
replacing them one by one anyway. First one I swapped, it all lit up
when I tried it again, so I swapped the 'old' bulb back in, still
worked, so I figured maybe it had worked loose from the heat or something.

Then a few days back I noticed in the periphery of my vision that the
lights (again, just this one set) seemed to be intermittently going
brighter. I've seen this sometimes when the supply's been a bit ropey,
but nothing else was affected. It cleared up, and I thought no more of
it.

Tonight, having had the lights on a couple of times today, I discover
the entire set is out again. Having changed the bulbs one by one it's
still not working, and I'm none the wiser.

Having left it off and tried again, it's still dead. I'm not taking the
cover off till I can see what I'm doing tomorrow when the sun makes an
appearance again, but would appreciate some ideas on what I can look for
and try.

I have a multimeter and have a vague idea on how to use it, though most
of my experience has been on much lower voltage stuff, not mains, which
is another reason why I'm leaving it till tomorrow, so I can see exactly
what I'm about to electrocute myself with :-)

Anyone else had this, I'm assuming it must be something to do with the
transformer, but a bit puzzled why changing the bulb last time seemed to
kick it back into life. I've checked all the track is secure and tight
etc.

TIA,

Velvet
Had the same problem. The track lights or mini spots in my case got so hot
they melted. Currently trying to replace same at a cost of about £80.00 for
4.

Regards JD

r3duf wrote:

"Velvet" wrote in message
...

Put up two sets of these a couple of years ago. One set is now behaving
oddly. They're both operated from the same switch, but I'm not exactly
sure how they're wired together, I didn't do that bit.

They're 12v systems with a transformer integral to the mounting point on
the ceiling for the track - so not recessed at all. 4x35w halogen
lights on the track, one transformer per track.

A couple of weeks ago, one set didn't come on. From past experience I
know if a single halogen blows, the others remain lit, but started
replacing them one by one anyway. First one I swapped, it all lit up
when I tried it again, so I swapped the 'old' bulb back in, still
worked, so I figured maybe it had worked loose from the heat or something.

Then a few days back I noticed in the periphery of my vision that the
lights (again, just this one set) seemed to be intermittently going
brighter. I've seen this sometimes when the supply's been a bit ropey,
but nothing else was affected. It cleared up, and I thought no more of

it.

Tonight, having had the lights on a couple of times today, I discover
the entire set is out again. Having changed the bulbs one by one it's
still not working, and I'm none the wiser.

Having left it off and tried again, it's still dead. I'm not taking the
cover off till I can see what I'm doing tomorrow when the sun makes an
appearance again, but would appreciate some ideas on what I can look for
and try.

I have a multimeter and have a vague idea on how to use it, though most
of my experience has been on much lower voltage stuff, not mains, which
is another reason why I'm leaving it till tomorrow, so I can see exactly
what I'm about to electrocute myself with :-)

Anyone else had this, I'm assuming it must be something to do with the
transformer, but a bit puzzled why changing the bulb last time seemed to
kick it back into life. I've checked all the track is secure and tight

etc.

TIA,

Velvet
Had the same problem. The track lights or mini spots in my case got so hot

they melted. Currently trying to replace same at a cost of about £80.00 for
4.

Regards JD



Hmm. Mine run hot, but I expect that of halogens - certainly they've
never got hot enough to melt anything! I did find a cheap set of
mini-spots (non-halogen) ran hot enough that they literally fell apart,
having cause the crappy welding to fail where the housing meets the
adjustable arm bit. Mine have all but the narrow bit on the bulb
exposed (they're sealed bulb things c/w reflector and front uv-glass) so
the heat radiates away better than if they were enclosed and just had
the fronts showing (more like traditional incandescent spots tend to be).

There was absolutely no sign of heat damage when I was up there changing
the bulbs either - I'd expect the little 'max 35w' labels to have
crisped if they were getting seriously hot, but they all look fine.

Velvet

Velvet wrote on Monday (09/02/2004) :
Would something along the lines of what you describe cause the intermittent
brightening of them though? like an irregular pulse of brightness then
dropping back to normal again (or alternatively a pulse back to proper
brightness then dropping back to slightly dim). It's very hard to see, not
very noticeable at all, but my vision is very sensitive to changes in light
levels around the periphery (part of the reason why I now have these instead
of the ghastly flourescent that used to be up there).

The brightening could be a symptom of the switch mode power supply
("tranformer") becoming confused due to a poor connection to the track,
but it could equally be a symptom of a fault in the switch mode power
supply.

Could you perhaps take it back to your supplier for replacement?

--

Regards,
Harry (M1BYT) (Lap)
http://www.ukradioamateur.org

Harry Bloomfield wrote:

As the voltage goes down, the quantity of current has to rise to make up
for it to achieve the same wattage.

They do what now?

In an Ohmic resistor, the current is *proportional* to the voltage.
There is no magical way with which you can "raise the quantity of
current" to make up for a drop in the applied voltage.

--
Grunff

Mine had springy contacts in each lampholder to make contact with the
conducting bars. Dust and cheap manufacturing had caused poor contacts in
each holder. A strip and clean sorted it.

--


Regards

John


"Velvet" wrote in message
...
r3duf wrote:

"Velvet" wrote in message
...

Put up two sets of these a couple of years ago. One set is now behaving
oddly. They're both operated from the same switch, but I'm not exactly
sure how they're wired together, I didn't do that bit.

They're 12v systems with a transformer integral to the mounting point on
the ceiling for the track - so not recessed at all. 4x35w halogen
lights on the track, one transformer per track.

A couple of weeks ago, one set didn't come on. From past experience I
know if a single halogen blows, the others remain lit, but started
replacing them one by one anyway. First one I swapped, it all lit up
when I tried it again, so I swapped the 'old' bulb back in, still
worked, so I figured maybe it had worked loose from the heat or
something.

Then a few days back I noticed in the periphery of my vision that the
lights (again, just this one set) seemed to be intermittently going
brighter. I've seen this sometimes when the supply's been a bit ropey,
but nothing else was affected. It cleared up, and I thought no more of

it.

Tonight, having had the lights on a couple of times today, I discover
the entire set is out again. Having changed the bulbs one by one it's
still not working, and I'm none the wiser.

Having left it off and tried again, it's still dead. I'm not taking the
cover off till I can see what I'm doing tomorrow when the sun makes an
appearance again, but would appreciate some ideas on what I can look for
and try.

I have a multimeter and have a vague idea on how to use it, though most
of my experience has been on much lower voltage stuff, not mains, which
is another reason why I'm leaving it till tomorrow, so I can see exactly
what I'm about to electrocute myself with :-)

Anyone else had this, I'm assuming it must be something to do with the
transformer, but a bit puzzled why changing the bulb last time seemed to
kick it back into life. I've checked all the track is secure and tight

etc.

TIA,

Velvet
Had the same problem. The track lights or mini spots in my case got so
hot

they melted. Currently trying to replace same at a cost of about £80.00
for
4.

Regards JD



Hmm. Mine run hot, but I expect that of halogens - certainly they've
never got hot enough to melt anything! I did find a cheap set of
mini-spots (non-halogen) ran hot enough that they literally fell apart,
having cause the crappy welding to fail where the housing meets the
adjustable arm bit. Mine have all but the narrow bit on the bulb
exposed (they're sealed bulb things c/w reflector and front uv-glass) so
the heat radiates away better than if they were enclosed and just had
the fronts showing (more like traditional incandescent spots tend to be).

There was absolutely no sign of heat damage when I was up there changing
the bulbs either - I'd expect the little 'max 35w' labels to have
crisped if they were getting seriously hot, but they all look fine.

Velvet



---
All of my outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.577 / Virus Database: 366 - Release Date: 03/02/2004

John wrote:

Mine had springy contacts in each lampholder to make contact with the
conducting bars. Dust and cheap manufacturing had caused poor contacts in
each holder. A strip and clean sorted it.


Ah, that's a point. I can get the entire track down, not sure how far
the individual units will strip, but I'll have a look at that tomorrow.

Harry, I'd get nowhere taking them back to the supplier - no longer
proof of purchase, and I doubt they make the same units any more (twas
one of the sheds).

My family are heavily biased in the electronics/electric skills, so
there's a possibility of fixing if it's the transformer that has a fault
- I'm just interested in working out what it is as well as I can before
I start asking for a visit from them :-) If it's something simple that
I can fix then it's less hassle all around, really!

Velvet

Velvet wrote:

John wrote:

Mine had springy contacts in each lampholder to make contact with the
conducting bars. Dust and cheap manufacturing had caused poor contacts in
each holder. A strip and clean sorted it.


Ah, that's a point. I can get the entire track down, not sure how far
the individual units will strip, but I'll have a look at that tomorrow.


If they won't strip down far enough you could try blasting them with an
electronic cleaning solvent aerosol - removes dirt, grease, and oxide
film, great stuff. Not sure where you would get it locally though, I
used to buy it from work who got it from RS, Farnell, CPC, or similar.

Harry, I'd get nowhere taking them back to the supplier - no longer
proof of purchase, and I doubt they make the same units any more (twas
one of the sheds).

My family are heavily biased in the electronics/electric skills, so
there's a possibility of fixing if it's the transformer that has a fault
- I'm just interested in working out what it is as well as I can before
I start asking for a visit from them :-) If it's something simple that
I can fix then it's less hassle all around, really!

Velvet

Parish wrote:

Velvet wrote:

John wrote:

Mine had springy contacts in each lampholder to make contact with the
conducting bars. Dust and cheap manufacturing had caused poor
contacts in
each holder. A strip and clean sorted it.


Ah, that's a point. I can get the entire track down, not sure how far
the individual units will strip, but I'll have a look at that tomorrow.


If they won't strip down far enough you could try blasting them with an
electronic cleaning solvent aerosol - removes dirt, grease, and oxide
film, great stuff. Not sure where you would get it locally though, I
used to buy it from work who got it from RS, Farnell, CPC, or similar.


That's another good idea (well done uk.diy!) - the chances are that one
of my family have such a thing

Velvet

Velvet wrote:


Anyone else had this, I'm assuming it must be something to do with the
transformer, but a bit puzzled why changing the bulb last time seemed to
kick it back into life. I've checked all the track is secure and tight
etc.



Yes, interminably. In my case it is the contacts between the transformer
unit and the rails. They are simply NOT good enough for the current in a
steamy kitchen.

Usually woggling the transformer fixes it: Occasionally I take it all
apart and file back the areced contact areas.



TIA,

Velvet

Velvet wrote:

Harry Bloomfield wrote:

Velvet wrote on Monday (09/02/2004) :

Put up two sets of these a couple of years ago. One set is now
behaving oddly. They're both operated from the same switch, but I'm
not exactly sure how they're wired together, I didn't do that bit.

They're 12v systems with a transformer integral to the mounting point
on the ceiling for the track - so not recessed at all. 4x35w halogen
lights on the track, one transformer per track.



Many of these LV units suffer the same problem, high current causing
burnt and poor connections.

As the voltage goes down, the quantity of current has to rise to make
up for it to achieve the same wattage. If all lights are out on a
track, then look at the connections between the "transformer" and the
track. If it unplugs from the track check for signs of burning and
blackening.

Less likely, but still worth checking are the mains connections to the
"transformer".

Failing either of the above, there could be a problem inside the
"transformer".

Thanks, I was going to give it a quick visual for that sort of thing.
There's no evidence between transformer and track - it's the sort where
the track is a pair of rigid metal poles, with a screw clamping them
into place against each of a drop-pole. Hard to describe - they slot in
between two fingers, which have a fairly wide screw-thread on the inside
surfaces, and the big screw thus screws up from the bottom to apply
pressure both between itself and the track, and between track and upper
surface of mount.

Would something along the lines of what you describe cause the
intermittent brightening of them though? like an irregular pulse of
brightness then dropping back to normal again (or alternatively a pulse
back to proper brightness then dropping back to slightly dim). It's
very hard to see, not very noticeable at all, but my vision is very
sensitive to changes in light levels around the periphery (part of the
reason why I now have these instead of the ghastly flourescent that used
to be up there).



Yes. Bad cionnection on teh LV side. If they are all 'in harmony' its
transformer-to-track. If one goes dim as the other goes bright, its
track-to-light.


Velvet

Grunff wrote:

Harry Bloomfield wrote:

As the voltage goes down, the quantity of current has to rise to make
up for it to achieve the same wattage.


They do what now?

In an Ohmic resistor, the current is *proportional* to the voltage.
There is no magical way with which you can "raise the quantity of
current" to make up for a drop in the applied voltage.


Switched mode power supplies are anything but ohmic.

The Natural Philosopher wrote:

As the voltage goes down, the quantity of current has to rise to make
up for it to achieve the same wattage.



They do what now?

In an Ohmic resistor, the current is *proportional* to the voltage.
There is no magical way with which you can "raise the quantity of
current" to make up for a drop in the applied voltage.


Switched mode power supplies are anything but ohmic.


I'm well aware of that - but if a switcher needs to push more current
through a filament bulb, the only way it can do so is by increasing the
applied voltage. This is not what the first two lines (quoted) of this
post say.

--
Grunff

The Lord alerted my mind to the presence of this EVIL article by Harry
Bloomfield, and I thusly replied:

Velvet wrote on Monday (09/02/2004) :
Put up two sets of these a couple of years ago. One set is now
behaving oddly. They're both operated from the same switch, but I'm
not exactly sure how they're wired together, I didn't do that bit.

They're 12v systems with a transformer integral to the mounting point
on the ceiling for the track - so not recessed at all. 4x35w halogen
lights on the track, one transformer per track.

Many of these LV units suffer the same problem, high current causing
burnt and poor connections.

As the voltage goes down, the quantity of current has to rise to make
up for it to achieve the same wattage. If all lights are out on a
track, then look at the connections between the "transformer" and the
track. If it unplugs from the track check for signs of burning and
blackening.

Less likely, but still worth checking are the mains connections to the
"transformer".

Failing either of the above, there could be a problem inside the
"transformer".

Why is "transformer" in quote marks?

--
The Reverend Parson Peter Parsnip
Smiting Sinful Usenet Users Since 1874

"A ******* shall not enter into the congregation of the Lord; even to his
tenth generation shall he not enter into the congregation of the Lord."
- Deuteronomy 23:2

The Lord alerted my mind to the presence of this EVIL article by Harry
Bloomfield, and I thusly replied:

Could you perhaps take it back to your supplier for replacement?

Shame we can't do that with you.

--
The Reverend Parson Peter Parsnip
Smiting Sinful Usenet Users Since 1874

"A ******* shall not enter into the congregation of the Lord; even to his
tenth generation shall he not enter into the congregation of the Lord."
- Deuteronomy 23:2

"Grunff" wrote in message
...

As the voltage goes down, the quantity of current has to rise to
make up for it to achieve the same wattage.

[...] but if a switcher needs to push more current through a filament
bulb, the only way it can do so is by increasing the applied voltage.
This is not what the first two lines (quoted) of this post say.

Can I be allowed to disagree? I think you're tilting at a windmill. He
(Harry) didn't say that "as the voltage goes down the current rises ..." but
rather that the "current has to rise ...". IOW 12V lamps will take ~20
times as much current as mains voltage ones of the same power. That's all.

--
Andy