Hello,
I have a piece of audio gear which has an illuminated power switch. The LED
inside flickers. Should I replace the LED, or is something else at play
here? I was under the impression (for no good reason) that LEDs are like
light bulbs - either they work or they don't -- no flickering.
Thanks!!
Fred

"Fred Mann" wrote in message
...
Hello,
I have a piece of audio gear which has an illuminated power switch. The
LED
inside flickers. Should I replace the LED, or is something else at play
here? I was under the impression (for no good reason) that LEDs are like
light bulbs - either they work or they don't -- no flickering.
Thanks!!
Fred



Probably lead-free soldering cracking up!

Fred-

Your concern about LED's flickering:

Is valid. LEDs do not flicker unless the applied voltage varies. They can be used to transmit information via light to another device at high frequency, or can remain on steadily without any variation in intensity for years.

Check the applied voltage with a meter, and check the connections. LED's are Solid State devices (Light Emitting Diode). I have never come across an intermittent one. They will fail open or shorted if subjected to conditions outside of normal, such as high temperature and voltage spikes. It's possibly a problem with the switch innards.

It's possible that you have a neon pilot light in that switch? They will flicker at end of useful life.


RKic

"ian field" writes:

"Fred Mann" wrote in message
...
Hello,
I have a piece of audio gear which has an illuminated power switch. The LED
inside flickers. Should I replace the LED, or is something else at play
here? I was under the impression (for no good reason) that LEDs are like
light bulbs - either they work or they don't -- no flickering.

Probably lead-free soldering cracking up!

Are you sure it's an LED? Neon lamps flicker when they get old.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

Fred Mann wrote:

Hello,
I have a piece of audio gear which has an illuminated power switch. The
LED inside flickers. Should I replace the LED, or is something else at
play here? I was under the impression (for no good reason) that LEDs are
like light bulbs - either they work or they don't -- no flickering.
Thanks!!
Fred

Are you sure it isn't a neon tube? They do sometimes flicker when they are
old.

Chris

"Chris Jones" wrote in message
...
Fred Mann wrote:

Hello,
I have a piece of audio gear which has an illuminated power switch. The
LED inside flickers. Should I replace the LED, or is something else at
play here? I was under the impression (for no good reason) that LEDs are
like light bulbs - either they work or they don't -- no flickering.
Thanks!!
Fred

Are you sure it isn't a neon tube? They do sometimes flicker when they
are
old.

Chris

I took the switch apart, and the "light" may in fact be a neon tube. It
looks like a very small condom with a reservoir tip (sorry, but that's just
what it looks like. I'm not sure if this is an LED, but the size is similar.
Thanks again,
Fred

Fred Mann wrote:

Hello,
I have a piece of audio gear which has an illuminated power switch. The LED
inside flickers. Should I replace the LED, or is something else at play
here? I was under the impression (for no good reason) that LEDs are like
light bulbs - either they work or they don't -- no flickering.
Thanks!!
Fred


If it flickers, it is a neon bulb.

Fred Mann wrote:

"Chris Jones" wrote in message
...

Fred Mann wrote:


Hello,
I have a piece of audio gear which has an illuminated power switch. The
LED inside flickers. Should I replace the LED, or is something else at
play here? I was under the impression (for no good reason) that LEDs are
like light bulbs - either they work or they don't -- no flickering.
Thanks!!
Fred

Are you sure it isn't a neon tube? They do sometimes flicker when they

are

old.

Chris


I took the switch apart, and the "light" may in fact be a neon tube. It
looks like a very small condom with a reservoir tip (sorry, but that's just
what it looks like. I'm not sure if this is an LED, but the size is similar.
Thanks again,
Fred


Yup! NE-2 or similar.

On Wed, 12 Jul 2006 21:34:59 -0400, the renowned "Fred Mann"
wrote:


"Chris Jones" wrote in message
...
Fred Mann wrote:

Hello,
I have a piece of audio gear which has an illuminated power switch. The
LED inside flickers. Should I replace the LED, or is something else at
play here? I was under the impression (for no good reason) that LEDs are
like light bulbs - either they work or they don't -- no flickering.
Thanks!!
Fred

Are you sure it isn't a neon tube? They do sometimes flicker when they
are
old.

Chris

I took the switch apart, and the "light" may in fact be a neon tube. It
looks like a very small condom with a reservoir tip (sorry, but that's just
what it looks like. I'm not sure if this is an LED, but the size is similar.
Thanks again,
Fred

Yes, it's a neon. The tip is where they sealed off the glass tube in a
hot flame.

You can replace the neon bulb itself, but take note of the series
resistor and size of the envelope (for example):

http://www.chefung.com/neon/neon.html

If you mismatch the resistor and the neon you'll either get too little
light or shorten the lifetime.


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

"Spehro Pefhany" wrote in message
...
On Wed, 12 Jul 2006 21:34:59 -0400, the renowned "Fred Mann"
wrote:


"Chris Jones" wrote in message
...
Fred Mann wrote:

Hello,
I have a piece of audio gear which has an illuminated power switch.
The
LED inside flickers. Should I replace the LED, or is something else
at
play here? I was under the impression (for no good reason) that LEDs
are
like light bulbs - either they work or they don't -- no flickering.
Thanks!!
Fred

Are you sure it isn't a neon tube? They do sometimes flicker when they
are
old.

Chris

I took the switch apart, and the "light" may in fact be a neon tube. It
looks like a very small condom with a reservoir tip (sorry, but that's
just
what it looks like. I'm not sure if this is an LED, but the size is
similar.
Thanks again,
Fred

Yes, it's a neon. The tip is where they sealed off the glass tube in a
hot flame.

You can replace the neon bulb itself, but take note of the series
resistor and size of the envelope (for example):

http://www.chefung.com/neon/neon.html

If you mismatch the resistor and the neon you'll either get too little
light or shorten the lifetime.


Best regards,
Spehro Pefhany


Thanks! Is my local electronics store likely to have a replacement? If so,
will the resistor be matched up with the bulb when I buy it, or do I have to
bring the original resistor in (I accidentally chopped it in half trying to
bypass it -- don't ask).
Thanks yet again!!!!!
Fred

Fred Mann wrote:
"Spehro Pefhany" wrote in message
...

On Wed, 12 Jul 2006 21:34:59 -0400, the renowned "Fred Mann"
wrote:


"Chris Jones" wrote in message
...

Fred Mann wrote:


Hello,
I have a piece of audio gear which has an illuminated power switch.

The

LED inside flickers. Should I replace the LED, or is something else

at

play here? I was under the impression (for no good reason) that LEDs

are

like light bulbs - either they work or they don't -- no flickering.
Thanks!!
Fred

Are you sure it isn't a neon tube? They do sometimes flicker when they

are

old.

Chris

I took the switch apart, and the "light" may in fact be a neon tube. It
looks like a very small condom with a reservoir tip (sorry, but that's

just

what it looks like. I'm not sure if this is an LED, but the size is

similar.

Thanks again,
Fred

Yes, it's a neon. The tip is where they sealed off the glass tube in a
hot flame.

You can replace the neon bulb itself, but take note of the series
resistor and size of the envelope (for example):

http://www.chefung.com/neon/neon.html

If you mismatch the resistor and the neon you'll either get too little
light or shorten the lifetime.


Best regards,
Spehro Pefhany



Thanks! Is my local electronics store likely to have a replacement? If so,
will the resistor be matched up with the bulb when I buy it, or do I have to
bring the original resistor in (I accidentally chopped it in half trying to
bypass it -- don't ask).
Thanks yet again!!!!!
Fred

Hi...

Someone up there likes you!

Be very very thankful that your attempt to bypass it failed

Take care.

Ken

Go to your local electronics store, and ask for an NE-2. If the mains
voltage is 120 VAC, ask for a 120 kohm 1/4 Watt resistor. If the mains is
220 VAC, ask for a 220 kohm 1/4 Watt resistor.

As for the resistor, it is not very critical. For 120 VAC, you can use
anything from about 100 kohm to about 140 kohm. Double this value for 220
VAC operation. If you go higher with the resistor value, the lamp will be a
little dimmer. If you go lower, the lamp will be a little brighter. If you
go too low, its lifespan will be reduced.

You may have to buy these parts in a minimum quantity, unless the dealer has
opened packages of these parts in stock. Most distributors have a minimum
invoicing. You may have to shop around for a small quantity.

--

JANA
_____


"Fred Mann" wrote in message
. ..

"Spehro Pefhany" wrote in message
...
On Wed, 12 Jul 2006 21:34:59 -0400, the renowned "Fred Mann"
wrote:


"Chris Jones" wrote in message
...
Fred Mann wrote:

Hello,
I have a piece of audio gear which has an illuminated power switch.
The
LED inside flickers. Should I replace the LED, or is something else
at
play here? I was under the impression (for no good reason) that LEDs
are
like light bulbs - either they work or they don't -- no flickering.
Thanks!!
Fred

Are you sure it isn't a neon tube? They do sometimes flicker when they
are
old.

Chris

I took the switch apart, and the "light" may in fact be a neon tube. It
looks like a very small condom with a reservoir tip (sorry, but that's
just
what it looks like. I'm not sure if this is an LED, but the size is
similar.
Thanks again,
Fred

Yes, it's a neon. The tip is where they sealed off the glass tube in a
hot flame.

You can replace the neon bulb itself, but take note of the series
resistor and size of the envelope (for example):

http://www.chefung.com/neon/neon.html

If you mismatch the resistor and the neon you'll either get too little
light or shorten the lifetime.


Best regards,
Spehro Pefhany


Thanks! Is my local electronics store likely to have a replacement? If so,
will the resistor be matched up with the bulb when I buy it, or do I have to
bring the original resistor in (I accidentally chopped it in half trying to
bypass it -- don't ask).
Thanks yet again!!!!!
Fred

On 2006-07-13, Fred Mann wrote:


You can replace the neon bulb itself, but take note of the series
resistor and size of the envelope (for example):

http://www.chefung.com/neon/neon.html

If you mismatch the resistor and the neon you'll either get too little
light or shorten the lifetime.


Best regards,
Spehro Pefhany


Thanks! Is my local electronics store likely to have a replacement?

that depends on how good they are.

If so,
will the resistor be matched up with the bulb when I buy it, or do I have to
bring the original resistor in (I accidentally chopped it in half trying to
bypass it -- don't ask).
Thanks yet again!!!!!
Fred

it may be easier (but not cheaper) to replace the whole switch with another neon illuminated
switch.

OTOH you should be able to get the data on your replacement neon so you can
pick the apropriate resistor for it and the voltage it's supplied from.


--

Bye.
Jasen

"JANA" wrote in message
...
Go to your local electronics store, and ask for an NE-2. If the mains
voltage is 120 VAC, ask for a 120 kohm 1/4 Watt resistor. If the mains is
220 VAC, ask for a 220 kohm 1/4 Watt resistor.

As for the resistor, it is not very critical. For 120 VAC, you can use
anything from about 100 kohm to about 140 kohm. Double this value for 220
VAC operation. If you go higher with the resistor value, the lamp will be
a
little dimmer. If you go lower, the lamp will be a little brighter. If you
go too low, its lifespan will be reduced.

You may have to buy these parts in a minimum quantity, unless the dealer
has
opened packages of these parts in stock. Most distributors have a minimum
invoicing. You may have to shop around for a small quantity.

--

JANA



Thanks all!!! I got it working.
Fred

JANA wrote:

Go to your local electronics store, and ask for an NE-2. If the mains
voltage is 120 VAC, ask for a 120 kohm 1/4 Watt resistor. If the mains is
220 VAC, ask for a 220 kohm 1/4 Watt resistor.

As for the resistor, it is not very critical. For 120 VAC, you can use
anything from about 100 kohm to about 140 kohm. Double this value for 220
VAC operation. If you go higher with the resistor value, the lamp will be
a little dimmer. If you go lower, the lamp will be a little brighter. If
you go too low, its lifespan will be reduced.

You may have to buy these parts in a minimum quantity, unless the dealer
has opened packages of these parts in stock. Most distributors have a
minimum invoicing. You may have to shop around for a small quantity.


Also many 1/4W resistors are not rated for 240VAC use, but you might be able
to put two in series to get sufficient voltage rating if you can't get the
proper rating in a single resistor from your source of components.

Chris

On Wed, 12 Jul 2006 17:13:15 -0400, "Fred Mann"
wrote:

Hello,
I have a piece of audio gear which has an illuminated power switch. The LED
inside flickers. Should I replace the LED, or is something else at play
here? I was under the impression (for no good reason) that LEDs are like
light bulbs - either they work or they don't -- no flickering.
Thanks!!
Fred


Fred, as it happens I noticed this same symptom on my pre-amp today. I
was playing a CD and noticed the green power-on LED go off and then
flicker dimly before coming on again. Since I built the pre-amp myself
about 15 years back I am confident the soldering is ok and the
resistors were all 1% Beyschlag metal film so I doubt it is due to
this component. My guess, from the dim background flickering and then
normal brightness, is that the LED is failing. I will let you know
more when I have had a good look. And yes, I have seen LED's exhibit
this symptom before.

"Fred Mann" wrote in message
...
Hello,
I have a piece of audio gear which has an illuminated power switch. The
LED
inside flickers. Should I replace the LED, or is something else at play
here? I was under the impression (for no good reason) that LEDs are like
light bulbs - either they work or they don't -- no flickering.
Thanks!!
Fred


Unless the circuit board/connection was failing, LED's don't flicker, they
just go to "silicon heaven".

Graham

In article , Grey wrote:

"Fred Mann" wrote in message
.. .
Hello,
I have a piece of audio gear which has an illuminated power switch. The
LED inside flickers. Should I replace the LED, or is something else at
play here? I was under the impression (for no good reason) that LEDs
are like light bulbs - either they work or they don't -- no flickering.

Unless the circuit board/connection was failing, LED's don't flicker, they
just go to "silicon heaven".

Some LEDs of recent years have come from manufacturers shoddy enough to
make some of their clunkers manage to flicker! (I have seen millions of
LEDs, hundreds of different part numbers, with as far as I can tell all
with semiconductor material excluding silicon for that matter!)

Meanwhile, I would still investigate other explanations, such as
intermittent contact in a bad solder joint or the flickering lamp being an
aged neon lamp! Illuminmated power switches to this day continue to
mostly use neon lamps, and those often flicker when they have accumulated
10,000-30,000 operating hours where the AC line voltage is 120 or so
(as opposed to 230 or so, where neon lamps with appropriate resistors can
run much longer with merely fading before they start flickering).

- Don Klipstein )

what you are describing is generally a neon tube

--
Art

"Fred Mann" wrote in message
. ..

"Chris Jones" wrote in message
...
Fred Mann wrote:

Hello,
I have a piece of audio gear which has an illuminated power switch. The
LED inside flickers. Should I replace the LED, or is something else at
play here? I was under the impression (for no good reason) that LEDs
are
like light bulbs - either they work or they don't -- no flickering.
Thanks!!
Fred

Are you sure it isn't a neon tube? They do sometimes flicker when they
are
old.

Chris

I took the switch apart, and the "light" may in fact be a neon tube. It
looks like a very small condom with a reservoir tip (sorry, but that's
just
what it looks like. I'm not sure if this is an LED, but the size is
similar.
Thanks again,
Fred

In the future Fred if you need onsie twosies on resistors in the 1/8 to 1/2
watt range just holler - I have tens of thousands (dont ask) and can stick a
few in an envelope for you no charge

--
Art

"Fred Mann" wrote in message
...

"JANA" wrote in message
...
Go to your local electronics store, and ask for an NE-2. If the mains
voltage is 120 VAC, ask for a 120 kohm 1/4 Watt resistor. If the mains
is
220 VAC, ask for a 220 kohm 1/4 Watt resistor.

As for the resistor, it is not very critical. For 120 VAC, you can use
anything from about 100 kohm to about 140 kohm. Double this value for 220
VAC operation. If you go higher with the resistor value, the lamp will be
a
little dimmer. If you go lower, the lamp will be a little brighter. If
you
go too low, its lifespan will be reduced.

You may have to buy these parts in a minimum quantity, unless the dealer
has
opened packages of these parts in stock. Most distributors have a minimum
invoicing. You may have to shop around for a small quantity.

--

JANA



Thanks all!!! I got it working.
Fred