I replaced chip that was burned had a hole in it the pin where it mounts gone so I jumpered it to capacitor.when I test voltage on to transistors k4075 in middle pin I get 24 volts the side pins I get 1.4 volts.are these bad.
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Re: Phillips 42pfl7432 no backlight
Here is a picAttached Files -
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Re: Phillips 42pfl7432 no backlight
Here another picAttached FilesComment
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Re: Phillips 42pfl7432 no backlight
Here is a pic of the chip before I replaced itAttached FilesComment
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Re: Phillips 42pfl7432 no backlight
Hi,
this is the typical failure with these LG inverters. Did You do the modifications recommended by Philips? Just had this issue and could it solve it with the repair kit containing the BD9897, the TVS diodes, SMD resistors and MosFets.Comment
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Re: Phillips 42pfl7432 no backlight
ok i will try itComment
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Re: Phillips 42pfl7432 no backlight
On the mods do you do both are do you do one and if you do one which on is the best one to do.Comment
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Re: Phillips 42pfl7432 no backlight
You have to do Both of them.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Re: Phillips 42pfl7432 no backlight
I replaced the transistors and chip. Still back light did not work. I tested the transistors on master on top I get 24v on legs I get 1.4v on the slave transistors I get 24v on top and on legs I get 5.8 v.any ideas on what is causing my voltage to be low on transistor legs 1.4v. Also on master I see the blue light come on then dim out and turn off.Comment
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Re: Phillips 42pfl7432 no backlight
Does any one know the value of cap mc45 and diodes mzd2 and md5 on master inverter.any help would be appreciated I believe the diodes are shorted. ThanksComment
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Re: Phillips 42pfl7432 no backlight
Well I replaced the Zener diode mzd2 which was bad I replaced it with a 5.6 Zener diode which had the e2 marking and the tv is up and running.Comment
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Re: Phillips 42pfl7432 no backlight
Good job! do you have a pic of where the Zener diode was with the old or new diode as a reference for others because you did not list the D### number so we can find it. Whats the difference between Mod 1 and Mod 2 ? The Mod papers said it did not matter if Mod 1 was done. Are both Mod 1 and 2 required to work properly?
ThanksComment
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this tv is throwing me for a loop. do samsung tvs no longer have the backlight self test feature built into the power supply?
i tested the backlight with my LED tester and it lights up both strips. one of them reads 100v and the other reads 63.7v.
unplugged mainboard from power supply but left backlight plugged in, and then plugged psu wall power in. expected to see backlights light up but see nothing.
according to how ive diagnosed in the past, this would almost always be a bad power supply. replacement power supply was cheap like 20$ from ebay. but still i get not even... -
I bought this p2210f dell monitor to fix. Schematic is the same as p2210.
Behaviour is that monitors comes on but then backlight switches off almost instantly. If I look with flashlight I can still find the "No signal message". So definitely a backlight issue. Trying to advance the issue I proved that the protection circuit is switching off the backlight by shorting out C3 and resistor to disable the INL chip then re enable by removing the short.
This is where it gets interesting. When I disassembled the monitor to solder leads on c3 capacitor I noticed the backlight flickered... -
Hello all,
Am trying to figure out this backlight issue with this A1990 Macbook Pro.
Tests performed:
There is no backlight even with a good screen.
Backlight IC is receiving the correct support voltages.
Fuse F8400 ok
Current sense resistor R8400 ok
Backlight IC is receiving 3.3V on enable pin.
Backlight IC receiving voltage from PPBUS_G3H, aprox 12.5V.
Backlight IC receiving 5V from PP5V_G3S
Backlight IC BKLT_SCL and BKLT_SDA both measure 0.545V diode mode to ground
I2C_BKLT_SCL and I2C_BKLT_SDA both measure... -
Hello, got an iPad Pro A2378 12.9 5th gen with no backlight. Got another test unit without screen, tested the screen, still no backlight with the test unit.
Figured out the backlight on the screen was bad, ordred a new backlight from mobilesentrix, *carefully replaced it* without damaging the lcd, oh well.
Final result, issue is still there, the screen has no back lights. So i'm back to square one, with 3 hours less and 100$ out, issue still on the screen.
The panel is still ok, i can see the apple in the middle of the screen when it kicks in, just no backlight.
Anyone... -
Hi all,
I've got an LG Flatron 24EN33TA with a backlight issue. The problem began with the monitor not powering up after sitting for a long time (overnight or during the day throughout work). When I would wake the computer up, the backlight would flick on for a second then go out. Sometimes it would take many tries to get it to come on. Once the monitor came on, it worked flawlessly until another long duration of being powered off.
I thought the problem would be bad caps but I checked both of the caps on the board and they are fine. I also tried powering the monitor from...
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