Re: Issue with Westinghouse 19" LCD Monitor (large pics)
I fixed 4 or 5 of these at the beginning of the year but didn't know where to share my knowledge. Here is my post on AVSForum. All these monitors are still running strong. Note that I had a different idea on why they are failing. I suspect the 3913 part doesn't have this flaw.
Westinghouse L2046NV 20" LCD Backlight Out.
If you have a Westinghouse L2046NV with a DAC-19M005 power PCB and your fluorescent backlight is out, here is the solution. You will need a soldering iron, copper braided desoldering wire, thermal paste, and some skillz. You will have to replace the following components. Brackets are [optional]:
Through-Hole:
Q206, [Q205]
C204, CE101, [CE109]
[CE103], [CE104]
SMT (backside of PCB):
F200
Order these components from Mouser Electronics:
2x On Semi 60V 45A TO-220 N-Channel FET
863-NTP45N06LG
2x Aavid Thermalloy Heatsink for above FETs
532-7139DG
3x Nichicon 220uF 35V Capacitors
647-UHE1V221MPD
2x Nichicon 1000uF 25V Capacitors
647-UVZ1E102MPD
1x Bourns 4A 1210 SMT Fuse
652-SF-1206F400-2
I suspect that there is a flaw in the fluorescent inverter circuit that allows both NFETs to turn on at the same time (causing a short between some of the capacitors and ground). I further suspect that this only happens when the monitor comes out of standby mode. If this is the case, you may get increased life out of this fix by powering off the monitor, waking up your computer, THEN turning it back on rather than allowing the monitor to come out of standby on its own. You may get increased life even if you ignore this advice because of the added heatsinks and the low ESR capacitors that I chose.
If you find this information helpful, or if you repost it somewhere else please make a donation to the Salvation Army.
Gordon
I fixed 4 or 5 of these at the beginning of the year but didn't know where to share my knowledge. Here is my post on AVSForum. All these monitors are still running strong. Note that I had a different idea on why they are failing. I suspect the 3913 part doesn't have this flaw.
Westinghouse L2046NV 20" LCD Backlight Out.
If you have a Westinghouse L2046NV with a DAC-19M005 power PCB and your fluorescent backlight is out, here is the solution. You will need a soldering iron, copper braided desoldering wire, thermal paste, and some skillz. You will have to replace the following components. Brackets are [optional]:
Through-Hole:
Q206, [Q205]
C204, CE101, [CE109]
[CE103], [CE104]
SMT (backside of PCB):
F200
Order these components from Mouser Electronics:
2x On Semi 60V 45A TO-220 N-Channel FET
863-NTP45N06LG
2x Aavid Thermalloy Heatsink for above FETs
532-7139DG
3x Nichicon 220uF 35V Capacitors
647-UHE1V221MPD
2x Nichicon 1000uF 25V Capacitors
647-UVZ1E102MPD
1x Bourns 4A 1210 SMT Fuse
652-SF-1206F400-2
I suspect that there is a flaw in the fluorescent inverter circuit that allows both NFETs to turn on at the same time (causing a short between some of the capacitors and ground). I further suspect that this only happens when the monitor comes out of standby mode. If this is the case, you may get increased life out of this fix by powering off the monitor, waking up your computer, THEN turning it back on rather than allowing the monitor to come out of standby on its own. You may get increased life even if you ignore this advice because of the added heatsinks and the low ESR capacitors that I chose.
If you find this information helpful, or if you repost it somewhere else please make a donation to the Salvation Army.
Gordon
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