Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Default CRT monitor: flashes on screen and burnt smell

Recently, my Hyundai ImageQuest Q910 19" monitor has been acting
up. Occasionally, there would be flashes across the screen,
similar to what you get when a fridge shuts off nearby.

Over a week or two, the flashes become more frequent. One day,
there was a big one, spanning maybe 10% of the frame. Later that
day, I smelled something burning in the monitor and turned it
off in a hurry.

There is no obvious damage inside. Where would you look first ?

--
André Majorel URL:http://www.teaser.fr/~amajorel/
"No meetings were held, nor secret handshakes created, to allow a Seria-
list Elite to disenfranchise the (tonal) non conformist. None had to be."
-- Wendy Carlos
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Default CRT monitor: flashes on screen and burnt smell


"Andre Majorel" wrote in message
...
Recently, my Hyundai ImageQuest Q910 19" monitor has been acting
up. Occasionally, there would be flashes across the screen,
similar to what you get when a fridge shuts off nearby.

Over a week or two, the flashes become more frequent. One day,
there was a big one, spanning maybe 10% of the frame. Later that
day, I smelled something burning in the monitor and turned it
off in a hurry.

There is no obvious damage inside. Where would you look first ?

--
André Majorel URL:http://www.teaser.fr/~amajorel/
"No meetings were held, nor secret handshakes created, to allow a Seria-
list Elite to disenfranchise the (tonal) non conformist. None had to be."
-- Wendy Carlos


Does it actually still work ? First suspicion would have to be bad joints.
Could be almost anywhere such as PSU, HOP stage or CRT base. Have a tap
around with a long insulated stick such as a piece of wood dowel. If you do
it in subdued lighting, you might even be able to see the arcing from a bad
joint.

Arfa


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Default CRT monitor: flashes on screen and burnt smell

On 2009-01-10, Arfa Daily wrote:
"Andre Majorel" wrote in message
...

Recently, my Hyundai ImageQuest Q910 19" monitor has been acting
up. Occasionally, there would be flashes across the screen,
similar to what you get when a fridge shuts off nearby.

Over a week or two, the flashes become more frequent. One day,
there was a big one, spanning maybe 10% of the frame. Later that
day, I smelled something burning in the monitor and turned it
off in a hurry.

There is no obvious damage inside. Where would you look first ?


Does it actually still work ?


Yes. I've had to use it a couple times and had no problems,
though I haven't left it on longer than necessary (i.e. about a
minute each time).

First suspicion would have to be bad joints. Could be almost
anywhere such as PSU, HOP stage or CRT base. Have a tap around
with a long insulated stick such as a piece of wood dowel. If
you do it in subdued lighting, you might even be able to see
the arcing from a bad joint.


Thanks. What's HOP ? Horizontal Overnight Permission ?

--
André Majorel URL:http://www.teaser.fr/~amajorel/
"No meetings were held, nor secret handshakes created, to allow a Seria-
list Elite to disenfranchise the (tonal) non conformist. None had to be."
-- Wendy Carlos
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Default CRT monitor: flashes on screen and burnt smell

Andre Majorel wrote:

Recently, my Hyundai ImageQuest Q910 19" monitor has been acting
up. Occasionally, there would be flashes across the screen,
similar to what you get when a fridge shuts off nearby.

Over a week or two, the flashes become more frequent. One day,
there was a big one, spanning maybe 10% of the frame. Later that
day, I smelled something burning in the monitor and turned it
off in a hurry.

There is no obvious damage inside. Where would you look first ?

If that is a CRT monitor, the Fly back is suspect!.


http://webpages.charter.net/jamie_5"

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Default CRT monitor: flashes on screen and burnt smell


"Andre Majorel" wrote in message
...
On 2009-01-10, Arfa Daily wrote:
"Andre Majorel" wrote in message
...

Recently, my Hyundai ImageQuest Q910 19" monitor has been acting
up. Occasionally, there would be flashes across the screen,
similar to what you get when a fridge shuts off nearby.

Over a week or two, the flashes become more frequent. One day,
there was a big one, spanning maybe 10% of the frame. Later that
day, I smelled something burning in the monitor and turned it
off in a hurry.

There is no obvious damage inside. Where would you look first ?


Does it actually still work ?


Yes. I've had to use it a couple times and had no problems,
though I haven't left it on longer than necessary (i.e. about a
minute each time).

First suspicion would have to be bad joints. Could be almost
anywhere such as PSU, HOP stage or CRT base. Have a tap around
with a long insulated stick such as a piece of wood dowel. If
you do it in subdued lighting, you might even be able to see
the arcing from a bad joint.


Thanks. What's HOP ? Horizontal Overnight Permission ?

--
André Majorel URL:http://www.teaser.fr/~amajorel/


HOP is horizontal output. This stage is responsible primarily for producing
the high level signal that drives the horizontal deflection coils on the CRT
neck. However, it has a number of secondary functions such as the generation
of supplementary power supply rails, and pulses used by other circuitry.
Another function of this stage is to generate a very high DC voltage for the
CRT, and this is done by an overwind on a transformer. Other high voltages
for the CRT are also generated here. It is not uncommon, as Jamie says, for
those high internal voltages to cause insulation breakdown within the
transformer, and occasionally for them to cause a pin-hole puncture in the
transformer case. Usually, when this happens, you can see corona discharge
around the hole, or sometimes even lightning (!) if there is metal nearby.
You can often smell ozone also. However, from your description, it is less
likely that you have a faulty transformer, than a bad joint. Bad joints
often form on the pins of this transformer.

Arfa
"No meetings were held, nor secret handshakes created, to allow a Seria-
list Elite to disenfranchise the (tonal) non conformist. None had to be."
-- Wendy Carlos





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Default CRT monitor: flashes on screen and burnt smell

I have had this on some models of monitors. Most of the time it was
the flyback transformer and HV multiplier assembly. Sometimes the CRT
was arcing internally.

I don't want to dissapoint you, but you should be seriously shopping
for a new monitor.


Jerry G.

__


On Jan 10, 9:04*am, Andre Majorel wrote:
Recently, my Hyundai ImageQuest Q910 19" monitor has been acting
up. Occasionally, there would be flashes across the screen,
similar to what you get when a fridge shuts off nearby.

Over a week or two, the flashes become more frequent. One day,
there was a big one, spanning maybe 10% of the frame. Later that
day, I smelled something burning in the monitor and turned it
off in a hurry.

There is no obvious damage inside. Where would you look first ?

--
André Majorel URL:http://www.teaser.fr/~amajorel/
"No meetings were held, nor secret handshakes created, to allow a Seria-
list Elite to disenfranchise the (tonal) non conformist. None had to be."
* -- Wendy Carlos


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Default CRT monitor: flashes on screen and burnt smell

On Jan 11, 6:30*pm, "Jerry G." wrote:
I have had this on some models of monitors. Most of the time it was
the flyback transformer and HV multiplier assembly. Sometimes the CRT
was arcing internally.

I don't want to dissapoint you, but you should be seriously shopping
for a new monitor.

Jerry G.

__

On Jan 10, 9:04*am, Andre Majorel wrote:



Recently, my Hyundai ImageQuest Q910 19" monitor has been acting
up. Occasionally, there would be flashes across the screen,
similar to what you get when a fridge shuts off nearby.


Over a week or two, the flashes become more frequent. One day,
there was a big one, spanning maybe 10% of the frame. Later that
day, I smelled something burning in the monitor and turned it
off in a hurry.


There is no obvious damage inside. Where would you look first ?


--
André Majorel URL:http://www.teaser.fr/~amajorel/
"No meetings were held, nor secret handshakes created, to allow a Seria-
list Elite to disenfranchise the (tonal) non conformist. None had to be.."
* -- Wendy Carlos- Hide quoted text -


- Show quoted text -


Methinks he wanted to fix the son of a bitch he has now, not replace a
nice CRT with a crappy LCD.
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