Hello,

Wickes 1200mm fitting, new starter thing, new tubes. Symptoms occur with new tubes, and previous tubes.

The tubes sort of flicker, but not fully on and off, it's more like that cloudy / boiling effect that you see in CGI films of the surface of the sun, if you see what I'm scratching at.

Anyway, this is causing a perceptible change in light levels, not anything epilepsy-inducing, but enough to be frustrating.

Anyone have any idea what it could be due to?

Thanks in advance,

David Paste.

On Wednesday, January 2, 2013 1:20:34 AM UTC, wrote:

Hello,
Wickes 1200mm fitting, new starter thing, new tubes. Symptoms occur with new tubes, and previous tubes.
The tubes sort of flicker, but not fully on and off, it's more like that cloudy / boiling effect that you see in CGI films of the surface of the sun, if you see what I'm scratching at.
Anyway, this is causing a perceptible change in light levels, not anything epilepsy-inducing, but enough to be frustrating.
Anyone have any idea what it could be due to?
Thanks in advance,
David Paste.

If its only changing light level, usually due to faulty tubes. It can also be due to oxidised connections somewhere, but usually isnt. Are the tubes all from the same batch?

IIRC, and I may well not, insufficient mercury.


NT

But he said new and old tubes. When I could see this sort of effect seemed
to bug tubes when the room was cool and went away as the whole thing got
warmed up.

Brian

--
From the Sofa of Brian Gaff Reply address is active
wrote in message
...
On Wednesday, January 2, 2013 1:20:34 AM UTC, wrote:

Hello,
Wickes 1200mm fitting, new starter thing, new tubes. Symptoms occur with
new tubes, and previous tubes.
The tubes sort of flicker, but not fully on and off, it's more like that
cloudy / boiling effect that you see in CGI films of the surface of the
sun, if you see what I'm scratching at.
Anyway, this is causing a perceptible change in light levels, not
anything epilepsy-inducing, but enough to be frustrating.
Anyone have any idea what it could be due to?
Thanks in advance,
David Paste.

If its only changing light level, usually due to faulty tubes. It can also
be due to oxidised connections somewhere, but usually isnt. Are the tubes
all from the same batch?

IIRC, and I may well not, insufficient mercury.


NT

In article ,
wrote:
Hello,

Wickes 1200mm fitting, new starter thing, new tubes. Symptoms occur with
new tubes, and previous tubes.

The tubes sort of flicker, but not fully on and off, it's more like that
cloudy / boiling effect that you see in CGI films of the surface of the
sun, if you see what I'm scratching at.

Anyway, this is causing a perceptible change in light levels, not
anything epilepsy-inducing, but enough to be frustrating.

Anyone have any idea what it could be due to?

is the fitting earthed? That sort of problem can be casued by lack of an
earth.

--
From KT24

Using a RISC OS computer running v5.18

In article ,
writes:
Hello,

Wickes 1200mm fitting, new starter thing, new tubes. Symptoms occur with new tubes, and previous tubes.

The tubes sort of flicker, but not fully on and off, it's more like that cloudy / boiling effect that you see in CGI films of the surface of the sun, if you see what I'm scratching at.

Anyway, this is causing a perceptible change in light levels, not anything epilepsy-inducing, but enough to be frustrating.

Anyone have any idea what it could be due to?

Two effects I can think of that you might be describing...

The arc in the tube is not uniform across the whole area of the tube,
but forms a bright path (usually only nearer the tube ends) which snakes
round and round. This is caused by contamination in the gas. It can
happen just whilst the tube is new (first 100 hours or so use) if the
contamination is going to get absorbed somewhere inside the tube, or
it might persist forever if it's a badly made tube.

Rings of bright and dark areas on the tube which usually seem to move
up or down the tube. This is caused by too low vapour pressure, and
a significant proportion of the electrons becoming synchronised in
being accelerated by the tube voltage and reaching the energy level
required to displace a mercury ion at the same point, that appearing
light and the distance beween appearing darker. This goes as the
tube warms up and more mercury is released from the amalgam which
stores it in modern tubes (unless the tube has run out of mercury).

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Andrew Gabriel wrote:
In article ,
writes:
Hello,

Wickes 1200mm fitting, new starter thing, new tubes. Symptoms occur with new tubes, and previous tubes.

The tubes sort of flicker, but not fully on and off, it's more like that cloudy / boiling effect that you see in CGI films of the surface of the sun, if you see what I'm scratching at.

Anyway, this is causing a perceptible change in light levels, not anything epilepsy-inducing, but enough to be frustrating.

Anyone have any idea what it could be due to?

Two effects I can think of that you might be describing...

The arc in the tube is not uniform across the whole area of the tube,
but forms a bright path (usually only nearer the tube ends) which snakes
round and round. This is caused by contamination in the gas. It can
happen just whilst the tube is new (first 100 hours or so use) if the
contamination is going to get absorbed somewhere inside the tube, or
it might persist forever if it's a badly made tube.

Rings of bright and dark areas on the tube which usually seem to move
up or down the tube. This is caused by too low vapour pressure, and
a significant proportion of the electrons becoming synchronised in
being accelerated by the tube voltage and reaching the energy level
required to displace a mercury ion at the same point, that appearing
light and the distance beween appearing darker. This goes as the
tube warms up and more mercury is released from the amalgam which
stores it in modern tubes (unless the tube has run out of mercury).

Another thing I've noticed which can cause a similar effect on smaller
tubes is overdriving of the tube. In one case, this was a 12 volt
inverter unit, mislabelled as 24 Volt which was killing tubes after
about a month of intremittent use. That took some working out...

--
Tciao for Now!

John.

On 02/01/2013 09:06, Brian Gaff wrote:
But he said new and old tubes. When I could see this sort of effect seemed
to bug tubes when the room was cool and went away as the whole thing got
warmed up.

Brian

Search for fluorescent tube striations. I've seen these in old 8 foot
tubes (not mine). I have a pair of 5ft 58W on a Philips HF-Performer II
which do it only when cold for around a minute. it's only noticeable if
you look at the tube itself. Not sure if HF is better than 50Hz for
preventing it - on mine it is a temporary phenomena.

I also used to note the kind of spiral wave motion inside sometimes as well.
Also nowadays with my poor eyes I've become sensitive in large stores with
lots of lights to a kind of strobing effect that gives me a headache, its as
if a wave is moving across the expanse of a ceiling which is full of tubes
but of course I can only perceive the light as if it was through a very
steamed up window.

Boots seems to be the main contender for this.

Brian

--
From the Sofa of Brian Gaff Reply address is active
"Part Timer" wrote in message
...
On 02/01/2013 09:06, Brian Gaff wrote:
But he said new and old tubes. When I could see this sort of effect
seemed
to bug tubes when the room was cool and went away as the whole thing got
warmed up.

Brian

Search for fluorescent tube striations. I've seen these in old 8 foot
tubes (not mine). I have a pair of 5ft 58W on a Philips HF-Performer II
which do it only when cold for around a minute. it's only noticeable if
you look at the tube itself. Not sure if HF is better than 50Hz for
preventing it - on mine it is a temporary phenomena.

On Wednesday, January 2, 2013 9:20:35 AM UTC, charles wrote:

is the fitting earthed? That sort of problem can be casued by lack of an
earth.

They were in the last location, but not now. From reading the other replies, I am wondering if it is due to the temperature, as it occurs to me that I have only ever seen them run for a minute or two (they stay on longer, but I am not there to bask in their glory).

Cheers everyone.