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From: Bill Simpson on 3 Mar 2006 11:00
I tried to post this yesterday, but it didn't seem to show up.
Apologies if it's duplicated. Probably a Comcast problem.

I have a very unusual problem with an LCD monitor. I will try and be
descriptive as possible without being confusing.

When the adapter for the monitor is plugged directly into a wall
outlet, and there is always current to the wall outlet, I can turn the
monitor on and off normally. There are no problems.

When the adapter for the monitor is connected to my UPS and the UPS is
turned off and then back on, or when the adapter is plugged into a
wall outlet and then unplugged from the wall outlet and plugged back
in, I begin to have problems.

Specifically, in the two situations above, when booting the computer,
the monitor will "buzz" briefly, the picture will come on, and then go
off. It will do this several times during the boot sequence. It will
do it once at the bios, once at the Windows splash and then again at
the login screen. Upon each of the three occurrences mentioned, the
monitor will "buzz", the picture will come on briefly and then go off.

However?if I reboot the system several times, or when I'm at the last
login screen, turn the monitor on and off several times with its
switch, it will eventually stay on.

I have tested this monitor with different video cards and on different
systems, so it's not the video card or one specific box.

From the way the LCD is reacting, the problem seems to be similar to a
bad ballast in a fluorescent light, is this possible?

Any suggestions (except leave it plugged in all the time? Is there any
way to test this LCD with minimum equipment and knowledge?

Thanks in advance.

From: mistermaniac on 3 Mar 2006 17:31

Bill Simpson Wrote:
> I tried to post this yesterday, but it didn't seem to show up.
> Apologies if it's duplicated. Probably a Comcast problem.
>
> I have a very unusual problem with an LCD monitor. I will try and be
> descriptive as possible without being confusing.
>
> When the adapter for the monitor is plugged directly into a wall
> outlet, and there is always current to the wall outlet, I can turn the
> monitor on and off normally. There are no problems.
>
> When the adapter for the monitor is connected to my UPS and the UPS is
> turned off and then back on, or when the adapter is plugged into a
> wall outlet and then unplugged from the wall outlet and plugged back
> in, I begin to have problems.
>
> Specifically, in the two situations above, when booting the computer,
> the monitor will "buzz" briefly, the picture will come on, and then go
> off. It will do this several times during the boot sequence. It will
> do it once at the bios, once at the Windows splash and then again at
> the login screen. Upon each of the three occurrences mentioned, the
> monitor will "buzz", the picture will come on briefly and then go off.
>
> However?if I reboot the system several times, or when I'm at the last
> login screen, turn the monitor on and off several times with its
> switch, it will eventually stay on.
>
> I have tested this monitor with different video cards and on different
> systems, so it's not the video card or one specific box.
>
> From the way the LCD is reacting, the problem seems to be similar to a
> bad ballast in a fluorescent light, is this possible?
>
> Any suggestions (except leave it plugged in all the time? Is there any
> way to test this LCD with minimum equipment and knowledge?
>
> Thanks in advance.

When the screen goes "off" does it really goes off? It sounds like a
bad inverter or a bad ccfl.


--
mistermaniac
From: Arfa Daily on 3 Mar 2006 18:57

"mistermaniac" <mistermaniac.2447p1(a)diybanter.com> wrote in message
news:mistermaniac.2447p1(a)diybanter.com...
>
> Bill Simpson Wrote:
>> I tried to post this yesterday, but it didn't seem to show up.
>> Apologies if it's duplicated. Probably a Comcast problem.
>>
>> I have a very unusual problem with an LCD monitor. I will try and be
>> descriptive as possible without being confusing.
>>
>> When the adapter for the monitor is plugged directly into a wall
>> outlet, and there is always current to the wall outlet, I can turn the
>> monitor on and off normally. There are no problems.
>>
>> When the adapter for the monitor is connected to my UPS and the UPS is
>> turned off and then back on, or when the adapter is plugged into a
>> wall outlet and then unplugged from the wall outlet and plugged back
>> in, I begin to have problems.
>>
>> Specifically, in the two situations above, when booting the computer,
>> the monitor will "buzz" briefly, the picture will come on, and then go
>> off. It will do this several times during the boot sequence. It will
>> do it once at the bios, once at the Windows splash and then again at
>> the login screen. Upon each of the three occurrences mentioned, the
>> monitor will "buzz", the picture will come on briefly and then go off.
>>
>> However.if I reboot the system several times, or when I'm at the last
>> login screen, turn the monitor on and off several times with its
>> switch, it will eventually stay on.
>>
>> I have tested this monitor with different video cards and on different
>> systems, so it's not the video card or one specific box.
>>
>> From the way the LCD is reacting, the problem seems to be similar to a
>> bad ballast in a fluorescent light, is this possible?
>>
>> Any suggestions (except leave it plugged in all the time? Is there any
>> way to test this LCD with minimum equipment and knowledge?
>>
>> Thanks in advance.
>
> When the screen goes "off" does it really goes off? It sounds like a
> bad inverter or a bad ccfl.
>
>
> --
> mistermaniac

Yes, you need to establish this. It is very possible, if the monitor is
genuinely not starting after a period of being totally unpowered, that the
problem is actually the external power supply, which is pretty much certain
to be a switch mode type. I have had a number of these giving similar
symptoms to those you state, the cause being bad electrolytics, particularly
on the primary side. In general, when switchers have this sort of problem,
once you've persuaded them to come on, and the caps have warmed up a bit,
they will stay on. Try measuring the output voltage of the power supply,
after it's been off for a couple of hours. You may well find that there
isn't any, or what there is, is pulsing. You could also try hanging a low
wattage car bulb across the power supply output - say an interior light
bulb - if you can figure a way of getting a connection to the output plug.

Arfa


From: tvguy on 3 Mar 2006 21:03
It don`t sound like a bad inverter if it is running good when plugged
directly to the wall outlet. If it only does this when plugged into
the powersupply of the computer then this would be a problem of the
computers powersupply. Did you try to plug it into another computer
to see if you still have the same problem ? I would suggest to try
this first and see what happens.



> mistermaniacwrote:
Bill Simpson Wrote:
> I tried to post this yesterday, but it didn't seem to show up.
> Apologies if it's duplicated. Probably a Comcast problem.
>
> I have a very unusual problem with an LCD monitor. I will try and
be
> descriptive as possible without being confusing.
>
> When the adapter for the monitor is plugged directly into a wall
> outlet, and there is always current to the wall outlet, I can turn
the
> monitor on and off normally. There are no problems.
>
> When the adapter for the monitor is connected to my UPS and the UPS
is
> turned off and then back on, or when the adapter is plugged into a
> wall outlet and then unplugged from the wall outlet and plugged
back
> in, I begin to have problems.
>
> Specifically, in the two situations above, when booting the
computer,
> the monitor will "buzz" briefly, the picture will come on,
and then go
> off. It will do this several times during the boot sequence. It
will
> do it once at the bios, once at the Windows splash and then again
at
> the login screen. Upon each of the three occurrences mentioned,
the
> monitor will "buzz", the picture will come on briefly and
then go off.
>
> However?if I reboot the system several times, or when I'm at the
last
> login screen, turn the monitor on and off several times with its
> switch, it will eventually stay on.
>
> I have tested this monitor with different video cards and on
different
> systems, so it's not the video card or one specific box.
>
> From the way the LCD is reacting, the problem seems to be similar to
a
> bad ballast in a fluorescent light, is this possible?
>
> Any suggestions (except leave it plugged in all the time? Is there
any
> way to test this LCD with minimum equipment and knowledge?
>
> Thanks in advance.
>
When the screen goes "off" does it really goes off? It
sounds like a
bad inverter or a bad ccfl.


--
mistermaniac[/quote:50075f7ac7]

From: Arfa Daily on 4 Mar 2006 13:57

"tvguy" <no(a)spam.invalid> wrote in message
news:1A6Of.198994$H54.155366(a)fe03.news.easynews.com...
> It don`t sound like a bad inverter if it is running good when plugged
> directly to the wall outlet. If it only does this when plugged into
> the powersupply of the computer then this would be a problem of the
> computers powersupply. Did you try to plug it into another computer
> to see if you still have the same problem ? I would suggest to try
> this first and see what happens.
>
>
Maybe I read it wrong, but I don't think that this is what the guy was
saying. I read it as he was always using the external power unit, that came
with the LCD monitor, and if he left it plugged in the wall, ie with power
always available to this power supply, but with the monitor turned off, when
he came to switch the monitor on, it came on ok. If, however, he plugged in
to any power source that was turned off for periods of time eg his UPS, or
unplugged from the wall for any length of time, then when he came to put
power back on the PSU, and then tried immediately to switch on the monitor,
he got the buzzing, spitting failure to start up, which is typical of a
defective switching PSU, with bad electrolytics. Perhaps the OP can confirm
??

If this is actually the case, then all the stuff about Windows and rebooting
etc is probably a red herring. It just relates to the length of time all
this takes, which gives the power supply time to struggle to a startup.

Arfa


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