Monitor Doesn't Turn-on When Hot

[Nehmo Sergheyev]

At the nearby computer junk place, http://www.surplusexchange.org/, I got a
HP A4033A 19" monitor
http://www.griffintechnology.com/archive/monitors/Hewle12.html for $22. It
works okay until you turn it off. Then if you try to re-turn-on soon, the
Power Saving indicator comes on and the monitor doesn't. If I wait for it to
cool (I really don't know if temperature is the factor), and then turn-on,
it works normally. So should I put a fan on the vent holes? Or what should I
do, if I should do something?

 

[Arno Wagner]

At the nearby computer junk place, http://www.surplusexchange.org/, I got a
HP A4033A 19" monitor
http://www.griffintechnology.com/archive/monitors/Hewle12.html for $22. It
works okay until you turn it off. Then if you try to re-turn-on soon, the
Power Saving indicator comes on and the monitor doesn't. If I wait for it to
cool (I really don't know if temperature is the factor), and then turn-on,
it works normally. So should I put a fan on the vent holes? Or what should I
do, if I should do something?

Likely thermal or capacitor problem. You can try all sorts of
things, but the only reliable approach is a circuit-level
diagnosis of the problem. Might require a degree in EE to
be done properly.

Be careful before you change anythong on the inside, tamper with
electrical insulation or operate it without cover: There is both mains
voltage (possibly rectified and stepped up to 300V) and high-voltage
(15000V...30000V) in there. Both can kill you if you are unlucky.

Arno

 

[Guest]

I got a HP A4033A 19"
for $22. It works okay until you turn it off. Then if you try
to re-turn-on soon, the Power Saving indicator comes on and
the monitor doesn't. If I wait for it to cool (I really don't
know if temperature is the factor), and then turn-on, it
works normally. So should I put a fan on the vent holes?

The monitor already has all the vent holes it needs, and I haven't
heard of a monitor needing a fan, except for the old Zenith Flat
Tensioned monitor.

I'm rather certain that your monitor has an overheated resistor or
solder joint that makes contact when cold but expands and opens up
when hot. Any such resistor (may be burned or bulged) has to be
replaced (match resistance and tolerance ratings, and meet or exceed
power rating), but resoldering bad joints will restore them (add fresh
solder so its rosin will clean any oxidation). Cracks can be
invisible to the naked eye and require a magnifying glass to find, so
some technicians simply resolder everything, or at least everything
connected to components that are subject to mechanical stress
(connectors, heavy objects) or that run hot. I'd especially look for
bad solder around a thermistor because they normally run very hot. It
usually resembles a ceramic disk capacitor (normally green or black)
or may be a flat disk with wires welded to its sides. The circuit
board may be labelled TH, THERM, or NTC next to it.

www.repairfaq.org has a great deal of information about electronics
repair and precautions. Unplug the monitor from the AC outlet before
removing its cover, don let the monitor fall forward (it's
front-heavy), and don't bump or scratch the picture tube because it
can implode and then explode with enough force to shoot shards that
will lodge in the walls or your eyes.

 

[Franc Zabkar]

At the nearby computer junk place, http://www.surplusexchange.org/, I got a
HP A4033A 19" monitor
http://www.griffintechnology.com/archive/monitors/Hewle12.html for $22. It
works okay until you turn it off. Then if you try to re-turn-on soon, the
Power Saving indicator comes on and the monitor doesn't. If I wait for it to
cool (I really don't know if temperature is the factor), and then turn-on,
it works normally. So should I put a fan on the vent holes? Or what should I
do, if I should do something?

I would be looking for dried out electrolytic capacitors, probably on
the primary side of the power supply.


- Franc Zabkar

 

[Nehmo Sergheyev]

- Arno Wagner -

Likely thermal or capacitor problem. You can try all sorts of
things, but the only reliable approach is a circuit-level
diagnosis of the problem.

- Nehmo -
What's peculiar about the problem with this monitor (and I've only been
using it for two days) is that if it continues to be on, it will stay on. It
only fails if you remove the power or otherwise turn it off. Then it won't
come back on, but, when turned back on, goes into *its* Power Saving mode
(the Power Saving indicator on the monitor goes on).

If the problem were just heat, wouldn't it fail while running?

Also, even though I found a driver on Driverguide
http://members.driverguide.com/ , I can't seem to install it. In the Add
Hardware Wizard, if I select HP or Hewlett Packard, the monitor isn't
listed, although plenty of other HP products are. What am I doing wrong? And
can I run the old monitor even after I get this HP driver installed?

 

[Manny]

What's peculiar about the problem with this monitor
(and I've only been using it for two days) is that
if it continues to be on, it will stay on. It only
fails if you remove the power or otherwise turn it
off. Then it won't come back on, but, when turned
back on, goes into *its* Power Saving mode (the
Power Saving indicator on the monitor goes on).

If the problem were just heat, wouldn't it fail while running?

It could be the kick start circuit in the power supply,
which is needed only at turn-on, but if it's going into
power saving mode under the wrong conditions, check the
setup of the computer (turn off the power saving mode or
change the monitor turn-off mode to "blank screen")
(their absense activates power saving modes for the
monitor). The power-saving circuitry could have a flaw,
such as a bad connection or part that fails after it
heats up (very slight, fan won't help). But don't throw
away this monitor because any flaw is probably an inexpensive
repair, provided the labor is free.

 

[Nehmo Sergheyev]

- Manny -

It could be the kick start circuit in the power supply,
which is needed only at turn-on, but if it's going into
power saving mode under the wrong conditions, check the
setup of the computer (turn off the power saving mode or
change the monitor turn-off mode to "blank screen")

- Nehmo -
How do you change the turn-off mode to blank screen? Desktop > Properties >
Screen Saver > Power button > Power Schemes > There's only a drop-down for
how long to wait before turning off the monitor.

Is there something somewhere else, like in the BIOS?

- Manny -

(their absense activates power saving modes for the
monitor). The power-saving circuitry could have a flaw,
such as a bad connection or part that fails after it
heats up (very slight, fan won't help). But don't throw
away this monitor because any flaw is probably an inexpensive
repair, provided the labor is free.

- Nehmo -
Even in it's current condition, I won't throw it away. I just have my old
monitor handy should this one fail.

Actually, it seems when the computer turns the monitor off (lack of activity
for 30 minutes in the power settings), it comes back on without a problem.
It appears the problem happens when I turn it off via the button or plug. I
don't want to experiment now. I'm using it at the moment.

 

[Arno Wagner]

- Arno Wagner -

- Nehmo -
What's peculiar about the problem with this monitor (and I've only been
using it for two days) is that if it continues to be on, it will stay on. It
only fails if you remove the power or otherwise turn it off. Then it won't
come back on, but, when turned back on, goes into *its* Power Saving mode
(the Power Saving indicator on the monitor goes on).

If the problem were just heat, wouldn't it fail while running?

Yes, unless it is heat in a circuit that needs only to function
when the monitor is turned on. The whole problem sounds very much
like an issue with the power-up circuit. Unfortunately that is
hard to diagnose.

Also, even though I found a driver on Driverguide
http://members.driverguide.com/ , I can't seem to install it. In the Add
Hardware Wizard, if I select HP or Hewlett Packard, the monitor isn't
listed, although plenty of other HP products are. What am I doing wrong? And
can I run the old monitor even after I get this HP driver installed?

No idea, sorry.

Arno

 

[Arno Wagner]

- [...]

But don't throw
away this monitor because any flaw is probably an inexpensive
repair, provided the labor is free.

Yes, true. But a qualified EE costs a lot per hour. It could
be that such a level of competence is needed to repair this problem.
My advice would be to live with the problem and only if it gets
worse to try to repair it.

Arno

 

[larrymoencurly]

Likely thermal or capacitor problem. You can try all sorts of
things, but the only reliable approach is a circuit-level
diagnosis of the problem. Might require a degree in EE to
be done properly.

I have the opposite of an EE degree, a sociology degree. Not only
that, but m degree came from AZ State instead of a real college. Yet
I've fixed several monitors that were tossed by other people (the last
monitor I bought cost negative $30, after rebates), and almost always
the problem was minor, like a solder connection, capacitor, or shorted
transistor. I think that if I can fix monitors, then almost anybody
can.

 

[Arno Wagner]

I have the opposite of an EE degree, a sociology degree. Not only
that, but m degree came from AZ State instead of a real college. Yet
I've fixed several monitors that were tossed by other people (the last
monitor I bought cost negative $30, after rebates), and almost always
the problem was minor, like a solder connection, capacitor, or shorted
transistor. I think that if I can fix monitors, then almost anybody
can.

Depends on the problem. I am doing electronics as a hobby for
20 years now and I know that many problems can be diagnosed
without tools, because the component that is broken is obvious.

I said "the only reliable approach". If you have the time
and are a bit lucky, many electronics faults can indeed be
fixed with common sense and some dexterity. Others are hard to
find with experience, special equipment and an EE degree.

The case described by the OP sounds like such a hard case to me.
More like a subtle problem, e.g. a capacitor having lost some of
its capacity but not all or a circuit damaged parially by static
electricity.

Arno

 

[chrisv]

Depends on the problem. I am doing electronics as a hobby for
20 years now and I know that many problems can be diagnosed
without tools, because the component that is broken is obvious.

I said "the only reliable approach". If you have the time
and are a bit lucky, many electronics faults can indeed be
fixed with common sense and some dexterity. Others are hard to
find with experience, special equipment and an EE degree.

The case described by the OP sounds like such a hard case to me.
More like a subtle problem, e.g. a capacitor having lost some of
its capacity but not all or a circuit damaged parially by static
electricity.

Or a part that you know is bad, but you can't find a replacement.
Last time I tried to fix something of my own (an audio power amp), I
traced it to an NEC transistor that was impossible to find information
on or replacements for.

 

[Franc Zabkar]

Last time I tried to fix something of my own (an audio power amp), I
traced it to an NEC transistor that was impossible to find information
on or replacements for.

Discretes should be relatively easy to substitute. It's the hybrid
modules, eg STKxxxx, that are sometimes obsolete.

Can you remember the NEC number? Note that Japanese transistors often
drop the leading "2S" in the part number. For example, a 2SCxxxx part
may be stamped with Cxxxx.


- Franc Zabkar

 

[Arno Wagner]

Or a part that you know is bad, but you can't find a replacement.
Last time I tried to fix something of my own (an audio power amp), I
traced it to an NEC transistor that was impossible to find information
on or replacements for.

Yes, sometimes I think they do it on purpose. The last semiconductor
that failed on me was the chipset in my Sony Vaio. Sort of a
self-destruct mechanism, since it was inadequately cooled by
design. O.k., that is another issue.

One thing I seems to see a lot though is unmarked or insufficiently
marked chips and other components. Like they do not want these things
to be repairable.

On the other hand I had very little electronics failures in the
last years. The Vaio does not count, since that failure was obviously
engineered. I will never buy Sony computing equipment again, being
ripped off once is enough. Before that the las one I had were
fauly capacitors (in several instances). AFAIK this was a single
incident of industrial espionage gone wrong and was easy to
fix in all instances (except the one were I mismatched capacities
enough to get a resonance effect).

Arno

 

[larrymoencurly]

Or a part that you know is bad, but you can't find a replacement.
Last time I tried to fix something of my own (an audio power amp), I
traced it to an NEC transistor that was impossible to find information
on or replacements for.

www.bdent.com has a lot of data sheets, but they're under
"schematics".
Another place with information and parts for audio amplifiers is Audio
Lab of Georgia, and www.nteinc.com may at least give you the
parameters for transistors and diodes. As for web searches, I've had
much better luck by Googling the part number than by looking for
electronics websites, but sometimes adding "semiconductor" to the
company name will bring up their database, i.e.,
www.necsemiconductor.com (I don't know if that's an actual website),
but for Sanken you have to go to www.allegromicro.com.

 

[David Wang]

I would not fool around with the monitor's circuit boards. Especially, the
unit was purchased for $22. Just dump it and get another one form eBay.