Ok so here is the run down. I have picture but no backlight. I got the tv with a blown fuse. When I put a new fuse in it, it blew resistor R963 (red in first pic). After replacing that I checked some diodes and found 1 bad at D912 (in blue in first pic). Then I tested the mosfets mark in red and blue in second pic and found them bad and replaced them. Now when the tv is on I get picture but no backlight. The other thing is that I only get 1.5v DC at the invertor boards. So I was wondering if you guys think buying a working power supply will fix all problems? I can get 1 for $78 but dont want to waste the money if there is another problem. Please let me know what to check. All of the caps look fine on main and power board.
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Help with 42PFL5432D/37
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Re: Help with 42PFL5432D/37
I think the TV was hit by lightning or some type of power surge, me personally I don't continue working on sets that were damage under these conditions. What may happen is you may fix the TV but all the rest of the parts have taken some of the surge. But on the bright side is that you may fix the set and you will have a good working set. Good luck with this.
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Re: Help with 42PFL5432D/37
for a successful repair i think you should replace the major part of components in that PSU. you should start from the TEA1507P, the transistor(s), diodes and resistors. altogether components should be under 20$. and the most important thing; you'll enjoy every bit of your work.
if you dont succeed thant try plan B: getting a new PSU.
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Re: Help with 42PFL5432D/37
How would I go about doing that? Also would not getting 24v to the inverter cause the backlight not to come on?Last edited by burner6999; 07-03-2012, 11:53 AM.
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Re: Help with 42PFL5432D/37
The 24V from the power supply AND the BL_ON command from the main board are needed for the backlights inverter board to lght up the lamps, the tow MOSFET's: One is for the PFC circuits, and another one is for the 24V power supply section.
If you check the the DC voltage on that large 450V cap when the tV is on and you do get around 400VDC on that cap, it means the PFC is working, then you may have bad SMPS IC or other components that were damaged when the MOSFET went out. iT depends on haw far in troubleshooting down to component level you willing to do.
By, do you get 24VDC if you disconnect the cables to the Inverter board, since if the inverter boards draw too much current, it will shutdown the 24V power supply to protect itself.Last edited by budm; 07-03-2012, 12:43 PM.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=24809
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Re: Help with 42PFL5432D/37
I wouldn't rule a smoking resistor as lightning/surge damage.
Very strange that I've -never- encountered a piece of surge damaged electronics here in the UK. Why is it so common in US?
My immediate guess would be a failed FET possible due to the power supply controller becoming unstable due to bad caps, very common on this Philips/Magnavox chassis.Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.
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Re: Help with 42PFL5432D/37
Great news! good job.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=24809
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