R
Rene Lamontagne
any ideas why this monitor won,t work if the room temp is below 65 deg
Fahrenheit?
Regards, Rene
Fahrenheit?
Regards, Rene
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D
Don Phillipson
any ideas why this monitor won,t work if the room temp is below 65 deg
Fahrenheit?
Last time an LCD monitor failed here, I was told:
1. Most brands are now made with components bought as cheaply
as possible, viz. specifying minimum performance standards (rather
than maximum possible standards of function, service life etc.) --
so that most cheap monitors now fail after two or three years.
2. LED monitors last longer than LCD monitors.
Frequent replacement of monitors seems OK to most users
because video quality is still improving every year.
F
Flasherly
any ideas why this monitor won,t work if the room temp is below 65 deg
Fahrenheit?
Regards, Rene
It's due to negative thermionic residuals, of course, if contractual
disparity exists below some applied higher tangent characteristic of
presumptive operational modes.
D
David
At Sun, 10 Feb 2013 11:24:12 -0800, Flasherly rearranged some electrons to
write:
Or perhaps a positive amount of bullshit.
write:
It's due to negative thermionic residuals, of course, if contractual
disparity exists below some applied higher tangent characteristic of
presumptive operational modes.
Or perhaps a positive amount of bullshit.
T
The Daring Dufas
any ideas why this monitor won,t work if the room temp is below 65 deg
Fahrenheit?
Regards, Rene
I've had to repair several Viewsonic monitors that had bad electrolytic
capacitors in the power supply section. I replaced the factory caps with
the same value except the new ones had a higher voltage and temperature
rating. Another problem that will show up is cold solder joints, at a
lower temperature, the metal parts, leads and solder on the circuit
board can actually shrink and break a connection. If you have any
experience repairing electronics or you have a friend who repairs gear
down to board level, take a look at the circuit board where any through
the board components are mounted, if you see cracks around the solder
joints, that could be where your problem is. ^_^
TDD
T
The Daring Dufas
No (in another sense). Go to an electronics supply house and buy a
can of certifiably compressed Witch-Tit Air. While the components are
up and running normally, try spraying it topically/regionally to
isolate those same cracks (and most anything else otherwise
thermodynamically prone to jumping over the wall). I once had one of
those things upside down on a blanket, spread across the living room,
for board replacements. It was big and nasty and had too many damn
screws hidden inside a regular Chinese jigsaw puzzle. I've seen cold
air used in electronics repair shops, though, which could be nice to
know if one can't use it to duplicate expansion faults prior to going
deeper into the disassembly. I do know that in my case, I must of shot
off my mouth to the service/warranty dept. So, they inexplicably sent
me a replacement board ... must've been based on inadvertent
assumption of my self-professed expertise. When I couldn't fix the
monitor, however, the next person I talked to said I oughtn't have
done what I did, that free shipment for the return and replacement was
standard policy. Nice ... the guy in service that sent me that
board... quite the joker, eh...
I find most cold solder joints by visual inspection of a board and by
wiggling components and watching the leads where they go through the
circuit board. Freeze spray can actually damage some components if
you're not careful with it. Thermal intermittent malfunctions can be
the most difficult problems to find especially with large surface mount
components. I have an Apple laptop that has a factory defect where the
large surface mount video chip has defective solder connections under
the chip. The repair is to heat the chip in order to re-flow the solder
without damaging the chip. Regular canned air can be used to cool down
circuit boards without drenching them with liquid refrigerant and a hair
dryer or heat gun on the low setting can be used to cycle the circuit
board temperature. I've come across all sorts of strange malfunctions in
electrical/electronic gear caused by temperature changes during my work
in the field over the past four decades and I still haven't seen
everything but I've seen a lot. ^_^
TDD
F
Flasherly
I find most cold solder joints by visual inspection of a board and by
wiggling components and watching the leads where they go through the
circuit board. Freeze spray can actually damage some components if
you're not careful with it. Thermal intermittent malfunctions can be
the most difficult problems to find especially with large surface mount
components. I have an Apple laptop that has a factory defect where the
large surface mount video chip has defective solder connections under
the chip. The repair is to heat the chip in order to re-flow the solder
without damaging the chip. Regular canned air can be used to cool down
circuit boards without drenching them with liquid refrigerant and a hair
dryer or heat gun on the low setting can be used to cycle the circuit
board temperature. I've come across all sorts of strange malfunctions in
electrical/electronic gear caused by temperature changes during my work
in the field over the past four decades and I still haven't seen
everything but I've seen a lot. ^_^
TDD
You're making my ears hurt, even hearing it - heating chips to re-flow
surface-mount wave soldering. Cut&dry PCB swap-outs is about as far
as I've come. Do have an approaching-old 6L6 valved amp, though, that
may be exhibiting problems. Not sure yet, as I've got to try a fresh
matched pair, near-same specified tube substites for duplicating
runaway idle currents in one tube position (electron collector plates
eventually turn cherry red on questionable tubes of the same
nomenclature). Right now I've some "class A" converters stuck up in
there, direct base plug-in adapters for running entirely different
characteristic tubes at half-reduced output wattages. Great little
THD adapters that should be renamed to Can't Do No Harm. Anyway, I've
had it apart, and after one look at the component assembly, "styled
after" a '59 Fender Bassman couldn't be other than perfectly
sensible. Be hard to find something simpler for wetting one's feet to
a challenge in electronics (...schematics, tracing current flow, bulky
capacitors with lethal voltages -- what more could one ask for?).
T
The Daring Dufas
You're making my ears hurt, even hearing it - heating chips to re-flow
surface-mount wave soldering. Cut&dry PCB swap-outs is about as far
as I've come. Do have an approaching-old 6L6 valved amp, though, that
may be exhibiting problems. Not sure yet, as I've got to try a fresh
matched pair, near-same specified tube substites for duplicating
runaway idle currents in one tube position (electron collector plates
eventually turn cherry red on questionable tubes of the same
nomenclature). Right now I've some "class A" converters stuck up in
there, direct base plug-in adapters for running entirely different
characteristic tubes at half-reduced output wattages. Great little
THD adapters that should be renamed to Can't Do No Harm. Anyway, I've
had it apart, and after one look at the component assembly, "styled
after" a '59 Fender Bassman couldn't be other than perfectly
sensible. Be hard to find something simpler for wetting one's feet to
a challenge in electronics (...schematics, tracing current flow, bulky
capacitors with lethal voltages -- what more could one ask for?).
The most common cause of problems I've seen in tube type equipment is
the changing of component values due to the heat produced by the tube
type equipment itself. I've found resistors and capacitors that were
way out of spec. Of course in any old gear, the first thing to check
is the electrolytic capacitors, they may appear to be fine looking at
them but after so many years the things will dry out and cease to
function. Heat kills. ^_^
TDD
F
Flasherly
The most common cause of problems I've seen in tube type equipment is
the changing of component values due to the heat produced by the tube
type equipment itself. I've found resistors and capacitors that were
way out of spec. Of course in any old gear, the first thing to check
is the electrolytic capacitors, they may appear to be fine looking at
them but after so many years the things will dry out and cease to
function. Heat kills. ^_^
TDD
Go through it, measure and replace. Sounds like a good plan.
F
Flasherly
PS update- Swapped in those new Sovteks. Seems to have taken care of
it - 4hrs+ and no cherry bombs. Others apparently are bad tubes to
throw out. There's 3" PC fans I put in on both sides of the tube
plane (pwr strip in the bottom of the combo/case w/ a transformer
wired to them. Blows out hot air in the middle, above the speaker.)
Should dump it all since I use a 4x12" cab, anyway, and turn the thing
upside down with a makeshift chassis. No heat no cry.
it - 4hrs+ and no cherry bombs. Others apparently are bad tubes to
throw out. There's 3" PC fans I put in on both sides of the tube
plane (pwr strip in the bottom of the combo/case w/ a transformer
wired to them. Blows out hot air in the middle, above the speaker.)
Should dump it all since I use a 4x12" cab, anyway, and turn the thing
upside down with a makeshift chassis. No heat no cry.