I am looking for a good cheap source for generic EL panels for
some older equipment retrofit. Has anyone done EL panel replacement? Can
you just cut them down without damaging them?
How critical is the voltage range to drive them?

Bob



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"BOB URZ" wrote in message
...
I am looking for a good cheap source for generic EL panels for
some older equipment retrofit. Has anyone done EL panel replacement? Can
you just cut them down without damaging them?
How critical is the voltage range to drive them?

Bob


Sharp shears will cut them with little problem, but always measure to assure a
clean separation between the elements.

The voltage for most phosphors is about 85 to 135 Volts AC at about 400 to 800
hertz. They will work on 60 hertz at a reduced output.

It's also worth noting that the ones I use have the back conducting surface
exposed, so you need to cover it with insulating tape or laminate the whole
thing.



Sharp shears will cut them with little problem, but always measure to
assure a
clean separation between the elements.


Good advice from Clarence - I've made a couple that were short circuit.



The voltage for most phosphors is about 85 to 135 Volts AC at about 400 to
800
hertz. They will work on 60 hertz at a reduced output.

On Tue, 02 Nov 2004 19:33:59 -0600, BOB URZ
wrote:

I am looking for a good cheap source for generic EL panels for
some older equipment retrofit. Has anyone done EL panel replacement? Can
you just cut them down without damaging them?
How critical is the voltage range to drive them?

Yes you can cut them down, however, their life is shortened, in some
cases quite dramatically, due to the ingress of air.

sPoNiX

I didn't know that. Is this process prevented by laminating or is the
damage already done at the cutting time?


Gareth.



Yes you can cut them down, however, their life is shortened, in some
cases quite dramatically, due to the ingress of air.

sPoNiX

On Tue, 02 Nov 2004 19:33:59 -0600, BOB URZ
wrote:

I am looking for a good cheap source for generic EL panels for
some older equipment retrofit. Has anyone done EL panel replacement? Can
you just cut them down without damaging them?
How critical is the voltage range to drive them?

---
1. Good and cheap are sometimes mutually exclusive. How much do you
want to spend, say, per square inch?

2. I have.

3. Usually.

4. Not very. 90 to about 120VRMS will usually work OK. You can change
the brightness by varying the voltage and the color (somewhat) by
changing the frequency. Life to half-brightness varies inversely
with brightness and with frequency.


--
John Fields

"sPoNiX" wrote in message
...
On Tue, 02 Nov 2004 19:33:59 -0600, BOB URZ
wrote:

I am looking for a good cheap source for generic EL panels for
some older equipment retrofit. Has anyone done EL panel replacement? Can
you just cut them down without damaging them?
How critical is the voltage range to drive them?

Yes you can cut them down, however, their life is shortened, in some
cases quite dramatically, due to the ingress of air.


Moisture!
Perhaps I assumed too much.
Seal the edge with a strip of clear plastic tape!

"BOB URZ" wrote in message
...
| I am looking for a good cheap source for generic EL panels for
| some older equipment retrofit. Has anyone done EL panel replacement? Can
| you just cut them down without damaging them?
| How critical is the voltage range to drive them?
|
| Bob

http://www.allelectronics.com have various of these, cheap.

N

On Wed, 03 Nov 2004 18:00:52 GMT, "Clarence" wrote:


"sPoNiX" wrote in message
...
On Tue, 02 Nov 2004 19:33:59 -0600, BOB URZ
wrote:

I am looking for a good cheap source for generic EL panels for
some older equipment retrofit. Has anyone done EL panel replacement? Can
you just cut them down without damaging them?
How critical is the voltage range to drive them?

Yes you can cut them down, however, their life is shortened, in some
cases quite dramatically, due to the ingress of air.


Moisture!
Perhaps I assumed too much.
Seal the edge with a strip of clear plastic tape!

---
That won't stop anything.

--
John Fields

John Fields wrote:

On Tue, 02 Nov 2004 19:33:59 -0600, BOB URZ
wrote:

I am looking for a good cheap source for generic EL panels for
some older equipment retrofit. Has anyone done EL panel replacement? Can
you just cut them down without damaging them?
How critical is the voltage range to drive them?

---
1. Good and cheap are sometimes mutually exclusive. How much do you
want to spend, say, per square inch?

2. I have.

3. Usually.

4. Not very. 90 to about 120VRMS will usually work OK. You can change
the brightness by varying the voltage and the color (somewhat) by
changing the frequency. Life to half-brightness varies inversely
with brightness and with frequency.


Ok, the retrofit application i have has a display about 3/4" wide by
4" long. Plastic encased like a laminated card. The EL display
backlite is dead. Measuring the voltage with my fluke on AC scale measures
about 55 volts AC. Is this too low for operation? It seems to be powered by a
sealed step up module

Bob



--
John Fields



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"BOB URZ" wrote in message
...

| Ok, the retrofit application i have has a display about 3/4" wide by
| 4" long. Plastic encased like a laminated card. The EL display
| backlite is dead. Measuring the voltage with my fluke on AC scale measures
| about 55 volts AC. Is this too low for operation? It seems to be powered
by a
| sealed step up module

Might be enough - tried 120 VAC on the strip?

5" x 1" electroluminescent strip. Ivory in off-state. Glows green when
energized by 120 Vac or inverter. For backlighting control panels,
special-effects lighting, models etc. Solderable pins extend 0.2" beyond end
of panel. CAT# EL-5 Your Price: $3.50 each

http://www.allelectronics.com/cgi-bi...L-5&type=store

N

"NSM" wrote in message news:sMdid.66581$df2.36110@edtnps89...

"BOB URZ" wrote in message
...

| Ok, the retrofit application i have has a display about 3/4" wide by
| 4" long. Plastic encased like a laminated card. The EL display
| backlite is dead. Measuring the voltage with my fluke on AC scale measures
| about 55 volts AC. Is this too low for operation? It seems to be powered
by a
| sealed step up module

Might be enough - tried 120 VAC on the strip?


The EL is also frequency sensitive, since it IS a losey capacitor. If the
frequency of the 55 Volts was higher than the usual 400HZ it might be enough. I
have run El's on 50 - 75 V RMS at 1.8KHZ. Higher frequencies tend to have an
affect the color.


5" x 1" electroluminescent strip. Ivory in off-state. Glows green when
energized by 120 Vac or inverter. For backlighting control panels,
special-effects lighting, models etc. Solderable pins extend 0.2" beyond end
of panel. CAT# EL-5 Your Price: $3.50 each


http://www.allelectronics.com/cgi-bi...L-5&type=store

N

Clarence wrote:

"NSM" wrote in message news:sMdid.66581$df2.36110@edtnps89...

"BOB URZ" wrote in message
...

| Ok, the retrofit application i have has a display about 3/4" wide by
| 4" long. Plastic encased like a laminated card. The EL display
| backlite is dead. Measuring the voltage with my fluke on AC scale measures
| about 55 volts AC. Is this too low for operation? It seems to be powered
by a
| sealed step up module

Might be enough - tried 120 VAC on the strip?



The EL is also frequency sensitive, since it IS a losey capacitor. If the
frequency of the 55 Volts was higher than the usual 400HZ it might be enough. I
have run El's on 50 - 75 V RMS at 1.8KHZ. Higher frequencies tend to have an
affect the color.


Dont forget the type of fluke may be quite important - the waveform is
in general not sinusoidal, and beware the frequency response of the
meter. "When in doubt, scope it out." I invariably use a scope to see
whats going on, and (where appropriate) a meter for the actual
measurement. I've been caught too many times.....

nowadays I use my trusty HP3400A 10MHz AC thermal RMS meter, which cost
about US$50 - I miss those MIT junkfests on a sunday....

I have never chopped one to pieces, but the contaminant issue sounds
quite feasible. I last designed an EL backlight into a product 4 years
ago - at the time I put a lot of work into ascertaining the lifetime,
which is a strong function of temperature, voltage, frequency, sock
colour etc. IIRC the backlites I was using were rated about 2,000 hours,
and so I got the software to turn off the EL a few minutes after a
keypress. I also designed a decent smps to drive the thing - the asian
prefab EL drivers I looked at all had nasty waveforms, and were
seriously crappy (appalling layout, beating bjts to death etc) as well
as expensive and inconvenient to mount - which dies first, the EL or the
smps.....

Cheers
Terry

Terry Given wrote:
Clarence wrote:

"NSM" wrote in message
news:sMdid.66581$df2.36110@edtnps89...

"BOB URZ" wrote in message
...

| Ok, the retrofit application i have has a display about 3/4" wide by
| 4" long. Plastic encased like a laminated card. The EL display
| backlite is dead. Measuring the voltage with my fluke on AC scale
measures
| about 55 volts AC. Is this too low for operation? It seems to be
powered
by a
| sealed step up module

Might be enough - tried 120 VAC on the strip?



The EL is also frequency sensitive, since it IS a losey capacitor. If the
frequency of the 55 Volts was higher than the usual 400HZ it might be
enough. I
have run El's on 50 - 75 V RMS at 1.8KHZ. Higher frequencies tend to
have an
affect the color.


Dont forget the type of fluke may be quite important - the waveform is
in general not sinusoidal, and beware the frequency response of the
meter. "When in doubt, scope it out." I invariably use a scope to see
whats going on, and (where appropriate) a meter for the actual
measurement. I've been caught too many times.....

nowadays I use my trusty HP3400A 10MHz AC thermal RMS meter, which cost
about US$50 - I miss those MIT junkfests on a sunday....

I have never chopped one to pieces, but the contaminant issue sounds
quite feasible. I last designed an EL backlight into a product 4 years
ago - at the time I put a lot of work into ascertaining the lifetime,
which is a strong function of temperature, voltage, frequency, sock
colour etc. IIRC the backlites I was using were rated about 2,000 hours,
and so I got the software to turn off the EL a few minutes after a
keypress. I also designed a decent smps to drive the thing - the asian
prefab EL drivers I looked at all had nasty waveforms, and were
seriously crappy (appalling layout, beating bjts to death etc) as well
as expensive and inconvenient to mount - which dies first, the EL or the
smps.....

Cheers
Terry

2000 hours does not sound like a lot. What are the failure modes on a EL
display? Its not like it has a filament that burns out

Bob


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"Bob Urz" wrote in message ...
Terry Given wrote:
Clarence wrote:
"NSM" wrote in message
"BOB URZ" wrote in message

| Ok, the retrofit application i have has a display about 3/4" wide by
| 4" long. Plastic encased like a laminated card. The EL display
| backlite is dead. Measuring the voltage with my fluke on AC scale
measures
| about 55 volts AC. Is this too low for operation? It seems to be
powered
by a
| sealed step up module

Might be enough - tried 120 VAC on the strip?

The EL is also frequency sensitive, since it IS a losey capacitor. If the
frequency of the 55 Volts was higher than the usual 400HZ it might be
enough. I
have run El's on 50 - 75 V RMS at 1.8KHZ. Higher frequencies tend to
have an effect on the color.

Dont forget the type of fluke may be quite important - the waveform is
in general not sinusoidal, and beware the frequency response of the
meter. "When in doubt, scope it out." I invariably use a scope to see
whats going on, and (where appropriate) a meter for the actual
measurement. I've been caught too many times.....

nowadays I use my trusty HP3400A 10MHz AC thermal RMS meter, which cost
about US$50 - I miss those MIT junkfests on a sunday....

I have never chopped one to pieces, but the contaminant issue sounds
quite feasible. I last designed an EL backlight into a product 4 years
ago - at the time I put a lot of work into ascertaining the lifetime,
which is a strong function of temperature, voltage, frequency, sock
colour etc. IIRC the backlites I was using were rated about 2,000 hours,
and so I got the software to turn off the EL a few minutes after a
keypress. I also designed a decent smps to drive the thing - the asian
prefab EL drivers I looked at all had nasty waveforms, and were
seriously crappy (appalling layout, beating bjts to death etc) as well
as expensive and inconvenient to mount - which dies first, the EL or the
smps.....

Cheers
Terry

2000 hours does not sound like a lot. What are the failure modes on a EL
display? Its not like it has a filament that burns out

Bob

The Phosphor fatigues and dims. Lower stress levels will achieve a longer live
in some phosphors. However abt 5,000 hours is the most I've seen.

The Asian drivers are basically a blocking oscillator, and the wave form is
pretty distorted. However even a modified sine-wave-form will work and it
doesn't affect the life enough to detect in a few hundred units I tested.

"Clarence" wrote in message
. com...

| The Phosphor fatigues and dims. Lower stress levels will achieve a longer
live
| in some phosphors. However abt 5,000 hours is the most I've seen.
|
| The Asian drivers are basically a blocking oscillator, and the wave form
is
| pretty distorted. However even a modified sine-wave-form will work and it
| doesn't affect the life enough to detect in a few hundred units I tested.

What about the EL night lights? Do they last longer?

N

On Wed, 03 Nov 2004 23:13:15 -0600, the renowned Bob Urz
wrote:

2000 hours does not sound like a lot. What are the failure modes on a EL
display? Its not like it has a filament that burns out

Bob

They usually just lose brightness over time. The lifetime might be to
50% of the original brightness.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

"NSM" wrote in message news:nSjid.69491$df2.590@edtnps89...

"Clarence" wrote in message
. com...

| The Phosphor fatigues and dims. Lower stress levels will achieve a longer
live
| in some phosphors. However abt 5,000 hours is the most I've seen.
|
| The Asian drivers are basically a blocking oscillator, and the wave form
is
| pretty distorted. However even a modified sine-wave-form will work and it
| doesn't affect the life enough to detect in a few hundred units I tested.

What about the EL night lights? Do they last longer?

N

Somewhat, since they are operating on 120 Volts 60 Hertz, but there is a broad
specification for how much light is acceptable. EL Life is usually given when
the light for a specified excitation results in half the original level of
light. So in those terms NO, the night light doesn't last longer. But if you
allow that the night light is useful at one quarter the initial light, then you
might see 10,000 to 14,000 hours of it still lighting. Just not as bright.

If the sealed Phosphor gets moist, with the seal broken, it will fail in a
relatively short time.

Clarence wrote:

"Bob Urz" wrote in message ...

Terry Given wrote:

Clarence wrote:

"NSM" wrote in message

"BOB URZ" wrote in message

| Ok, the retrofit application i have has a display about 3/4" wide by
| 4" long. Plastic encased like a laminated card. The EL display
| backlite is dead. Measuring the voltage with my fluke on AC scale
measures
| about 55 volts AC. Is this too low for operation? It seems to be
powered
by a
| sealed step up module

Might be enough - tried 120 VAC on the strip?

The EL is also frequency sensitive, since it IS a losey capacitor. If the
frequency of the 55 Volts was higher than the usual 400HZ it might be
enough. I
have run El's on 50 - 75 V RMS at 1.8KHZ. Higher frequencies tend to
have an effect on the color.

Dont forget the type of fluke may be quite important - the waveform is
in general not sinusoidal, and beware the frequency response of the
meter. "When in doubt, scope it out." I invariably use a scope to see
whats going on, and (where appropriate) a meter for the actual
measurement. I've been caught too many times.....

nowadays I use my trusty HP3400A 10MHz AC thermal RMS meter, which cost
about US$50 - I miss those MIT junkfests on a sunday....

I have never chopped one to pieces, but the contaminant issue sounds
quite feasible. I last designed an EL backlight into a product 4 years
ago - at the time I put a lot of work into ascertaining the lifetime,
which is a strong function of temperature, voltage, frequency, sock
colour etc. IIRC the backlites I was using were rated about 2,000 hours,
and so I got the software to turn off the EL a few minutes after a
keypress. I also designed a decent smps to drive the thing - the asian
prefab EL drivers I looked at all had nasty waveforms, and were
seriously crappy (appalling layout, beating bjts to death etc) as well
as expensive and inconvenient to mount - which dies first, the EL or the
smps.....

Cheers
Terry

2000 hours does not sound like a lot. What are the failure modes on a EL
display? Its not like it has a filament that burns out

Bob


The Phosphor fatigues and dims. Lower stress levels will achieve a longer live
in some phosphors. However abt 5,000 hours is the most I've seen.

I'd be pretty happy with 5,000 hours


The Asian drivers are basically a blocking oscillator, and the wave form is
pretty distorted. However even a modified sine-wave-form will work and it
doesn't affect the life enough to detect in a few hundred units I tested.

What I liked least about the blocking ocillators was the current spikes
- they deliberately saturate the core, causing fairly high current
spikes, then lay the circuit out on a single sided PCB in such a way as
to maximise the loop area. Often they are truly rough on the
transistors, which are generally the cheapest, ****tiest transistors in
existence - these things are mostly manufactured down to extremely low
cost. I figured its a bit rough on the guy who spent $200,000 on his box
of tricks to have the backlight **** itself because we used a $1 piece
of junk to drive it.

I forget what chip I ended up using (along with an smt L etc), it gave
fairly sinusoidal waveforms, with nice low dV/dt, and ended up at the
same cost as the nasty little blocking oscillator. Much lower profile
though.

Cheers
Terry

"BOB URZ" wrote in message
...
I am looking for a good cheap source for generic EL panels for
some older equipment retrofit. Has anyone done EL panel replacement? Can
you just cut them down without damaging them?
How critical is the voltage range to drive them?

Bob



I've cut them before with success.

Try www.allelectronics.com for cheap surplus inverters to drive them.

"John Fields" wrote in message
...
On Wed, 03 Nov 2004 18:00:52 GMT, "Clarence" wrote:


"sPoNiX" wrote in message
...
On Tue, 02 Nov 2004 19:33:59 -0600, BOB URZ
wrote:

I am looking for a good cheap source for generic EL panels for
some older equipment retrofit. Has anyone done EL panel replacement?
Can
you just cut them down without damaging them?
How critical is the voltage range to drive them?

Yes you can cut them down, however, their life is shortened, in some
cases quite dramatically, due to the ingress of air.


Moisture!
Perhaps I assumed too much.
Seal the edge with a strip of clear plastic tape!

---
That won't stop anything.



How about one of those Seal-A-Meal things for sealing frozen food in plastic
bags?

"BOB URZ" wrote in message
...


John Fields wrote:

On Tue, 02 Nov 2004 19:33:59 -0600, BOB URZ
wrote:

I am looking for a good cheap source for generic EL panels for
some older equipment retrofit. Has anyone done EL panel replacement?
Can
you just cut them down without damaging them?
How critical is the voltage range to drive them?

---
1. Good and cheap are sometimes mutually exclusive. How much do you
want to spend, say, per square inch?

2. I have.

3. Usually.

4. Not very. 90 to about 120VRMS will usually work OK. You can change
the brightness by varying the voltage and the color (somewhat) by
changing the frequency. Life to half-brightness varies inversely
with brightness and with frequency.


Ok, the retrofit application i have has a display about 3/4" wide by
4" long. Plastic encased like a laminated card. The EL display
backlite is dead. Measuring the voltage with my fluke on AC scale measures
about 55 volts AC. Is this too low for operation? It seems to be powered
by a
sealed step up module

Bob


What're you measuring it with? The high frequency AC won't read correctly on
most multimeters, even some true RMS ones can't go that high. Try using an
oscilloscope if you have access to one.

2000 hours does not sound like a lot. What are the failure modes on a EL
display? Its not like it has a filament that burns out

Bob



The phosphor depreciates, the same happens with fluorescent lamps, the lumen
output steadily depreciates over the life of the lamp (but power consumption
remains the same) as the phosphors age. This is why most businesses replace
lamps after a set amount of time rather than waiting for them to fail
completely. Places that do that turn into a cave because half the lamps are
so depreciated at any given time. EL phosphors wear out even faster.

"James Sweet" wrote in message
news:1DCid.3454$xO1.1411@trnddc08...
|
|
| 2000 hours does not sound like a lot. What are the failure modes on a EL
| display? Its not like it has a filament that burns out

| The phosphor depreciates, the same happens with fluorescent lamps, the
lumen
| output steadily depreciates over the life of the lamp (but power
consumption
| remains the same) as the phosphors age. This is why most businesses
replace
| lamps after a set amount of time rather than waiting for them to fail
| completely. Places that do that turn into a cave because half the lamps
are
| so depreciated at any given time. EL phosphors wear out even faster.

The real reason why I would replace all the lamps after the first one or two
failed is that it's easier to get the ladder etc. out once, rather than do
it over and over as the lamps fail.

N

The real reason why I would replace all the lamps after the first one or
two
failed is that it's easier to get the ladder etc. out once, rather than do
it over and over as the lamps fail.

N


That's a reason too, but generally once two fail completely, they've all
been very dim for quite a while. It's hard to notice until you see a new one
side by side, then you realize the reason for the eyestrain. Unfortunatly
all too many people still operate discharge lamps with an incandescent
mentality, that if it still lights up it's good.

On Fri, 05 Nov 2004 03:38:03 GMT, "James Sweet"
wrote:


"BOB URZ" wrote in message
...


John Fields wrote:

On Tue, 02 Nov 2004 19:33:59 -0600, BOB URZ
wrote:

I am looking for a good cheap source for generic EL panels for
some older equipment retrofit. Has anyone done EL panel replacement?
Can
you just cut them down without damaging them?
How critical is the voltage range to drive them?

---
1. Good and cheap are sometimes mutually exclusive. How much do you
want to spend, say, per square inch?

2. I have.

3. Usually.

4. Not very. 90 to about 120VRMS will usually work OK. You can change
the brightness by varying the voltage and the color (somewhat) by
changing the frequency. Life to half-brightness varies inversely
with brightness and with frequency.


Ok, the retrofit application i have has a display about 3/4" wide by
4" long. Plastic encased like a laminated card. The EL display
backlite is dead. Measuring the voltage with my fluke on AC scale measures
about 55 volts AC. Is this too low for operation? It seems to be powered
by a
sealed step up module

Bob


What're you measuring it with? The high frequency AC won't read correctly on
most multimeters, even some true RMS ones can't go that high. Try using an
oscilloscope if you have access to one.

---
The truth is, it makes very little difference. The goal is to get the
thing to light up, not to determine, to the Nth degree, what's driving
it, so pretty much whatever the waveshape is is fine if it works.

--
John Fields

On Fri, 05 Nov 2004 09:00:55 -0600, John Fields wrote:
On Fri, 05 Nov 2004 03:38:03 GMT, "James Sweet"
"BOB URZ" wrote in message
John Fields wrote:
On Tue, 02 Nov 2004 19:33:59 -0600, BOB URZ
wrote:
I am looking for a good cheap source for generic EL panels for
some older equipment retrofit. Has anyone done EL panel replacement?
Can
you just cut them down without damaging them?
How critical is the voltage range to drive them?
1. Good and cheap are sometimes mutually exclusive. How much do you
want to spend, say, per square inch?
2. I have.
3. Usually.
4. Not very. 90 to about 120VRMS will usually work OK. You can change
the brightness by varying the voltage and the color (somewhat) by
changing the frequency. Life to half-brightness varies inversely
with brightness and with frequency.
Ok, the retrofit application i have has a display about 3/4" wide by
4" long. Plastic encased like a laminated card. The EL display
backlite is dead. Measuring the voltage with my fluke on AC scale measures
about 55 volts AC. Is this too low for operation? It seems to be powered
by a
sealed step up module

Bob


What're you measuring it with? The high frequency AC won't read correctly on
most multimeters, even some true RMS ones can't go that high. Try using an
oscilloscope if you have access to one.

---
The truth is, it makes very little difference. The goal is to get the
thing to light up, not to determine, to the Nth degree, what's driving
it, so pretty much whatever the waveshape is is fine if it works.

But the problem was, it wasn't lighting up at all. A failed power supply
could do that, couldn't it? 55V is noticeably less than 90V, albeit that
_could_ be attributable to the meter, of course.

I'm "only" a tech, but one aspect of troubleshooting is determining
exactly where the failure has taken place, and diagnosis can be
cheaper than shotgunning, especially if you have to make up a
custom part.

Thanks,
Rich

"Rich Grise" wrote in message
news
| But the problem was, it wasn't lighting up at all. A failed power supply
| could do that, couldn't it? 55V is noticeably less than 90V, albeit that
| _could_ be attributable to the meter, of course.
|
| I'm "only" a tech, but one aspect of troubleshooting is determining
| exactly where the failure has taken place, and diagnosis can be
| cheaper than shotgunning, especially if you have to make up a
| custom part.

1) It doesn't matter what frequency is used to test it with (surely?)

2) A Variac provides a variable AC source.

3) If it can't be made to work directly from a Variac at under 140 VAC it's
dead.

4) If it can be run from a Variac at a reasonable voltage it's OK

5) If it's OK, look to the inverter.

N

On Fri, 05 Nov 2004 18:32:27 +0000, NSM wrote:


"Rich Grise" wrote in message
news
| But the problem was, it wasn't lighting up at all. A failed power supply
| could do that, couldn't it? 55V is noticeably less than 90V, albeit that
| _could_ be attributable to the meter, of course.
|
| I'm "only" a tech, but one aspect of troubleshooting is determining
| exactly where the failure has taken place, and diagnosis can be
| cheaper than shotgunning, especially if you have to make up a
| custom part.

1) It doesn't matter what frequency is used to test it with (surely?)

When I was a kid we got one of the first EL night-lights - just a disk,
about 3" diam. (7 cm?) with a wall plug sticking out the back, so
evidently it was running on 60 Hz. For a sales gimmick, they included
a shiny new US penny, with the quip: "We'll even pay for your first
year's use of electricity!"

After about 10 years, it got a black spot that grew so fast that
the thing was useless in a few months.

I've also seen them run on, I presume, 400Hz, on the sides of USAF
fighter planes. I think their purpose was to be able to be seen to fly
formation in the dark.

Thanks,
Rich

"Rich Grise" wrote in message
news
After about 10 years, it got a black spot that grew so fast that
the thing was useless in a few months.

This happens when moisture gets under the lamination. I'm not sure of the
exact failure mechanism (what _precisely_ does the water do the to EL
material -- react with it? or just support growth of, e.g., mold that
subsequently destroys the material?) I had a similar experience to yours,
although in my case it only took ~5 years. I went to the company's web site
(http://www.limelite.com/) and found that the early models were known to
have such a problem but that supposedly it's been fixed.

---Joel

"Joel Kolstad" wrote in message
...
"Rich Grise" wrote in message
news
After about 10 years, it got a black spot that grew so fast that
the thing was useless in a few months.

This happens when moisture gets under the lamination. I'm not sure of the
exact failure mechanism (what _precisely_ does the water do the to EL
material -- react with it? or just support growth of, e.g., mold that
subsequently destroys the material?) I had a similar experience to yours,
although in my case it only took ~5 years. I went to the company's web
site
(http://www.limelite.com/) and found that the early models were known to
have such a problem but that supposedly it's been fixed.

---Joel

I think GE called their round nite lite a Panelescent. And they lasted
much longer than 2000 - 3000 hrs. I know we got 4 or 5 years out of a couple
of ours. And these were from the early sixties, you'd think they would have
better life now. One of the anesthesia ventilators we sell uses an EL
backlite for the LCD, and, as other posters have said, after about 2000
hours, the damn thing is so dim you can't make out the numbers anymore. Poor
design? Probably. Poor quality? Probably, but this is medical equipment!
regards,
Tom

"t.hoehler" wrote in message
news:dsUid.60854$R05.4182@attbi_s53...
"Joel Kolstad" wrote in message
...
"Rich Grise" wrote in message
news
After about 10 years, it got a black spot that grew so fast that
the thing was useless in a few months.

This happens when moisture gets under the lamination. I'm not sure of the
exact failure mechanism (what _precisely_ does the water do the to EL
material -- react with it? or just support growth of, e.g., mold that
subsequently destroys the material?) I had a similar experience to yours,
although in my case it only took ~5 years. I went to the company's web
site
(http://www.limelite.com/) and found that the early models were known to
have such a problem but that supposedly it's been fixed.

---Joel

I think GE called their round nite lite a Panelescent. And they lasted
much longer than 2000 - 3000 hrs. I know we got 4 or 5 years out of a couple
of ours. And these were from the early sixties, you'd think they would have
better life now. One of the anesthesia ventilators we sell uses an EL
backlite for the LCD, and, as other posters have said, after about 2000
hours, the damn thing is so dim you can't make out the numbers anymore. Poor
design? Probably. Poor quality? Probably, but this is medical equipment!
regards,
Tom



Last EL panel I designed a supply for was three panels 30 inches BY 120 inches.
They are going strong and haven't lost much light yet, But is has only been a
year and they are only on for 6 hours a day. That is about 2,000 hours.

On Sat, 06 Nov 2004 00:06:36 GMT, "Clarence" wrote:



Last EL panel I designed a supply for was three panels 30 inches BY 120 inches.
They are going strong and haven't lost much light yet, But is has only been a
year and they are only on for 6 hours a day. That is about 2,000 hours.


A good alternative to an EL panel would be an LED back light. I've
seen ones which were made of a woven plastic fiber optic sheet that
was illuminated by an LED. Life should be virtually unlimited.
Something like this might be a good replacement
Andy Cuffe

"Andy Cuffe" wrote in message
...
On Sat, 06 Nov 2004 00:06:36 GMT, "Clarence" wrote:



Last EL panel I designed a supply for was three panels 30 inches BY 120
inches.
They are going strong and haven't lost much light yet, But is has only been
a
year and they are only on for 6 hours a day. That is about 2,000 hours.


A good alternative to an EL panel would be an LED back light. I've
seen ones which were made of a woven plastic fiber optic sheet that
was illuminated by an LED. Life should be virtually unlimited.
Something like this might be a good replacement
Andy Cuffe


I wouldn't work for the ceiling in a woman's rest room! It is laminated to the
arched ceiling and overlaid with a floral pattern.

Hey, I only build the power supplies. An architect did the design.

Andy Cuffe wrote:
On Sat, 06 Nov 2004 00:06:36 GMT, "Clarence" wrote:


Last EL panel I designed a supply for was three panels 30 inches BY 120 inches.
They are going strong and haven't lost much light yet, But is has only been a
year and they are only on for 6 hours a day. That is about 2,000 hours.



A good alternative to an EL panel would be an LED back light. I've
seen ones which were made of a woven plastic fiber optic sheet that
was illuminated by an LED. Life should be virtually unlimited.
Something like this might be a good replacement
Andy Cuffe


I have built such backlights for LCD displays. We used a single
injection moulding for our light pipe/spreader, and had all the LEDs on
the same pcb as the LCD driver, micro,switches etc

Cheers
Terry

On Sat, 06 Nov 2004 02:12:52 -0500, the renowned Andy Cuffe
wrote:

On Sat, 06 Nov 2004 00:06:36 GMT, "Clarence" wrote:



Last EL panel I designed a supply for was three panels 30 inches BY 120 inches.
They are going strong and haven't lost much light yet, But is has only been a
year and they are only on for 6 hours a day. That is about 2,000 hours.


A good alternative to an EL panel would be an LED back light. I've
seen ones which were made of a woven plastic fiber optic sheet that
was illuminated by an LED. Life should be virtually unlimited.
Something like this might be a good replacement
Andy Cuffe


White LED lifetime is not unlimited.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

On Sat, 06 Nov 2004 10:11:18 -0500, Spehro Pefhany wrote:

On Sat, 06 Nov 2004 02:12:52 -0500, the renowned Andy Cuffe
wrote:

On Sat, 06 Nov 2004 00:06:36 GMT, "Clarence" wrote:



Last EL panel I designed a supply for was three panels 30 inches BY 120 inches.
They are going strong and haven't lost much light yet, But is has only been a
year and they are only on for 6 hours a day. That is about 2,000 hours.


A good alternative to an EL panel would be an LED back light. I've
seen ones which were made of a woven plastic fiber optic sheet that
was illuminated by an LED. Life should be virtually unlimited.
Something like this might be a good replacement
Andy Cuffe


White LED lifetime is not unlimited.

I probably wouldn't have come up with this, but yes, now that you
mention it, when I looked at ebay, they all seemed to give lifetime
figures, although ISTR something like 100,000 hours, which seems
like a lot. :-)

Cheers!
Rich