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TFT monitor repair tips

C

CheetahHugger

Hello,

Can anyone point me towards some websites which can be of
help when dealing with lcd monitor repair.
Schematics, panel reference lists, repair tips, troubleshooting...
Any help would be welcome as google wasn't so helpful.

Cheetah
 
J

Jerry G.

I don't want to dissapoint you, but component level service for the
LCD and Plasma display's are not normaly supported by any of the
manufactures. They are mainly serviced at the module level only, as
like servicing a PC computer. After warranty, they are usualy
considered not feasible to service, unless the fault is something
simple.

Full service manuals for many of these types of displays are usualy
difficult or impossible to obtain. After the warranty periods for most
of this type of technology is finished, spare modules and parts may
not be available unless you can find a scapper unit with good parts.
The exception is if you can find some generic parts that will work.

When factering in the cost of the circuit boards and the laour, the
dropping of the replacement cost, after warranty service is usualy
considered not worth the cost. When troubleshooting and servicing this
type of technology the tools, and instruntation required is fairly
expensive.

If you want to service these types of monitors, try to see if you can
negotiate warrenty contract with some of the manufactures. Be
prepaired to invest a fair amount of dollars to get going with this.


Jerry G.
 
J

James Sweet

CheetahHugger said:
Hello,

Can anyone point me towards some websites which can be of
help when dealing with lcd monitor repair.
Schematics, panel reference lists, repair tips, troubleshooting...
Any help would be welcome as google wasn't so helpful.

Cheetah

There's two fairly common problems with these which I've had good luck
repairing. One is the backlight CCFL tubes and inverter, and the other is
the power supply. Both of these areas can be fixed using basic
troubleshooting with little flat panel specific knowledge.
 
C

CheetahHugger

This is what i am looking for, especially tips and tricks engarding
those inverters.
As well any other tips, i don't wish to service the mainboard but
am sure that i can do a little more then just looking for a smashed
identical screen and swap the board.

Cheetah
 
J

justmanuals

I don't want to dissapoint you, but component levelservicefor the
LCD and Plasma display's are not normaly supported by any of the
manufactures. They are mainly serviced at the module level only, as
like servicing a PC computer. After warranty, they are usualy
considered not feasible toservice, unless the fault is something
simple.

http://www.justmanuals.com

Fullservicemanualsfor many of these types of displays are usualy
difficult or impossible to obtain. After the warranty periods for most
of this type of technology is finished, spare modules and parts may
not be available unless you can find a scapper unit with good parts.
The exception is if you can find some generic parts that will work.

When factering in the cost of the circuit boards and the laour, the
dropping of the replacement cost, after warrantyserviceis usualy
considered not worth the cost. When troubleshooting and servicing this
type of technology the tools, and instruntation required is fairly
expensive.

If you want toservicethese types of monitors, try to see if you can
negotiate warrenty contract with some of the manufactures. Be
prepaired to invest a fair amount of dollars to get going with this.

Jerry G.
 
M

Michael A. Terrell

CheetahHugger said:
Did I ask for spam?


Regular, Low Sodium, or Turkey?


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
 
M

Michael A. Terrell

CheetahHugger said:
Regular please, with a pepsi!

Cheetah


No Pepsi! Mountain Dew!!!


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
 
A

Andy Cuffe

Hello,

Can anyone point me towards some websites which can be of
help when dealing with lcd monitor repair.
Schematics, panel reference lists, repair tips, troubleshooting...
Any help would be welcome as google wasn't so helpful.

Cheetah

At least 8 out of 10 LCD monitors I see have power supply, or back
light inverter problems.

The most common power supply problem is defective caps. Poor quality
caps are finding their way into everything now. The bad ones will
have the tops bulging out, but it's usually best to replace them all
if a few are bad.

The inverters are more complicated to fix. Any number of things can
go wrong. I see bad transformers, shorted transistors, shorted
diodes, and bad caps. No schematics are available and the SMD
components are often not marked in any meaningful way. I have
repaired a lot of them, but it often requires doing a lot of research
to ID parts. Once thing you can check is the tiny surface mount fuse
on the inverter board. When they are blown, about half the time
there's nothing else wrong. Fortunately, the inverter is the one
board that can sometimes be replaced for a reasonable price.
Andy Cuffe

[email protected]
 
C

CheetahHugger

Andy Cuffe schreef:
At least 8 out of 10 LCD monitors I see have power supply, or back
light inverter problems.

The most common power supply problem is defective caps. Poor quality
caps are finding their way into everything now. The bad ones will
have the tops bulging out, but it's usually best to replace them all
if a few are bad.

The inverters are more complicated to fix. Any number of things can
go wrong. I see bad transformers, shorted transistors, shorted
diodes, and bad caps. No schematics are available and the SMD
components are often not marked in any meaningful way. I have
repaired a lot of them, but it often requires doing a lot of research
to ID parts. Once thing you can check is the tiny surface mount fuse
on the inverter board. When they are blown, about half the time
there's nothing else wrong. Fortunately, the inverter is the one
board that can sometimes be replaced for a reasonable price.
Andy Cuffe

[email protected]

Yes, this is what i found out as well, seems we are conned as usual
with bad quality caps.

Cheetah
 
There's two fairly common problems with these which I've had good luck
repairing. One is the backlight CCFL tubes and inverter, and the other is
the power supply. Both of these areas can be fixed using basic
troubleshooting with little flat panel specific knowledge.

How do you isolate a CCFL/inverter problem without swapping parts?
I have a panel with a backlight that goes out about two seconds after
power on. Transistor/diode junctions all look OK, no visible cap
problems,
tubes have no telltale black bands. Shorted transformer winding,
perhaps?
How to test for that?

Thanks,
TM
 
J

James Sweet

How do you isolate a CCFL/inverter problem without swapping parts?
I have a panel with a backlight that goes out about two seconds after
power on. Transistor/diode junctions all look OK, no visible cap
problems,
tubes have no telltale black bands. Shorted transformer winding,
perhaps?
How to test for that?


I have a few lamps and inverters that are not in monitors, it's pretty easy
to wire one or the other up for testing without tearing things apart too
much.
 
C

CheetahHugger

I use a scanner lamp driver to test individual lamps in the screen.
Yesterday i fixed an inverter that was shutting down, it had a shorted
diode and a damn small one.
Cap problems are not always visible, i use the atlas esr60 meter and
it tells me a lot of caps simply go high esr but don't bulge.

Cheetah
 
The inverters are more complicated to fix. Any number of things can
go wrong. I see bad transformers, shorted transistors, shorted
diodes, and bad caps. No schematics are available and the SMD
components are often not marked in any meaningful way. I have
repaired a lot of them, but it often requires doing a lot of research
to ID parts.

Along those lines, I have a Sampo QPWBGL993IDLD inverter with a bad
transistor (Q8, one of two that drive the transformer windings). It's
an
SC-62/MPT3 package, with 'CF', 'Å', and 'RT' markings. After much
online research, I identified two possible devices that this could be:

Sanyo 2SC3650 NPN, 25V, 1.2A (hFE = 1500 typ)
http://www.ortodoxism.ro/datasheets/sanyo/ds_pdf_e/2SC3650.pdf
or
Rohm 2SD2150 NPN, 20V, 3A (hFE = 180-390)
http://datasheets.ru/datasheets/107892/data-2SD2150.html

Which one is it (or is it some other transistor)?

Thanks,
TM
 
J

justmanuals

Hello,

Can anyone point me towards some websites which can be of
help when dealing with lcd monitor repair.
Schematics, panel reference lists, repair tips, troubleshooting...
Any help would be welcome as google wasn't so helpful.

Cheetah

http://www.justmanuals.com
 
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