This TV had no power at all and no standby voltage.  There is a repair kit available for the power supply board DPS-411AP-1 at Shopjimmy.   There is a service manual online but no schematic for the power supply board.

Advice on badcaps suggested looking at the circuitry around IC901 (ICE3BS02G) which generates standby voltage as a separate circuit from the incoming AC.  Components to check include F2 (small red fuse),  R929, R903 and Q905.  R929 was open and I replaced it with a 2.2ohm 1/4 W fusible resistor.  It blew when I plugged it in and there was also visible damage on IC901.  I tested Q905 on my ESR tester and it was not shorted.

ICE3BS02G is obsolete but the manufacturer lists ICE3BS03LJG as a replacement and this part was available at Digikey (part #ICE3BS03LJGXUMA1CT-ND).  I also ordered a 1 ohm fusible resistor to replace R929 (Digikey part #1.00DCCT-ND).

When the parts came in, it was difficult to find the pin 1 marking on the IC.  Taking a pic of it, you can see it on the bottom left with the markings upright.

With the two parts replaced, the TV powered up.

This TV turned on but had no backlight. Suspecting bad LEDs, I took off the back cover and found the connector supplying the LED strips. There were six pairs of red/black wires which meant each strip was powered individually. I unplugged the connector and probed each set with my LED tester. I found that the top strip did not light up and the tester didn’t read a voltage which pointed to open LEDs. Taking apart the panel, I removed the strip and was able to change the bad LEDs with ones from a spare strip I had with similar voltage. My hot air reflow tip browned the area underneath the LED which casts a slightly noticeable shadow. This model doesn’t have a backlight level setting so I turned down the brightness.

Update: This TV came back with more LED failures on the same strip.  I ordered backlights on ebay but they didn’t match.  There are a least two different chassis used for this model.  My strips are IC-A-CNA050D173L &  IC-A-CNA050D173R.  These strips match model numbers Element ELEFW502, Seiki SE50FY10 and Westinghouse DW50F1Y1.  The other chassis uses the same strip throughout.

The backlight level can be lowered in the service menu.  With the TV on, hit menu – 1 -1 -4 -7 on the remote.  It may be under the panel setting.

I ordered a new remote and this didn’t work either since there appears to multiple versions of this model.

Failure of the LED backlight seems very common with the LN series from LG.  50LN5600 is another model with LED failures.  With the panel opened up, I found one bad LED with my LED tester.  I ordered a replacement right strip from a seller on Aliexpress for about $10 USD shipped epacket (typical 1-3 weeks to Canada).

Update: I am encountering quite a few failed 42LN5700 models with failed backlights.  It appears this model was a freebie given out by Telus for subscribing to Optik TV service.

Update 2:  It is recommended with backlight failures to replace all the strips with new vs repairing the bad ones.  All the LEDs have wear and are destined to fail.  LG LN Series Bad LED Backlights

There are a few videos on Youtube showing how to do LED replacement which is much cheaper than replacing the strip.  3V 2538 replacement LEDs for LG can be found fairly cheap on Aliexpress. Search LATWT470RELZK. 32″ LG TV’s may use 6V LEDs.

I have a hot air rework station to do the replacement. With the LG strips, you first need to pop off the lens with a screwdriver. Peel off the circular backing since this will melt under heat. I usually don’t add extra solder but do add some flux before soldering the new LED. Attaching the lens back is tricky since it has to sit level and be centered. I scrape off the old nubs with a razor scraper and use crazy glue with Zap Kicker accelerant dapped with a q-tip on the lens side.

I leave all the boards connected and remove just the LCD panel and the diffuser panels. With the LCD panel disconnected and TV plugged in, the LEDs should light up.

It is recommended to turn down the backlight level and install the latest firmware after replacement.

A common failure of this TV is a blown fusible resistor on the power supply.  There are three rectangular cement resistors at the corner of the board –  R927, R928 and R929  They should be marked 10 ohm and 5W.  They can be measured in circuit though out of circuit is more accurate.  All three should be replaced though typically only one blows..

Equivalent part can be obtained from Digikey part number TWW5J10RE-ND

Other model numbers:  LN46A550 LN46A550P3FXZC

A washed out screen or colour issues is a classic failure of the AS15F chip on the Tcon board.  It is difficult to replace because of the fine pitch of the package and replacement IC’s need to be ordered online.  It is easier to replace the whole board but used boards could also have the same failure if not tested beforehand.

For this TV, I also proactively replaced the Samwa capacitors on the power supply board BN44-00202A.  Values are as follows:

• CM871, CM872 –  470uF/25V
• CM876, CM881 – 820uF/25V
• CM852, CM853 – 1000uF/10V

I tested the old capacitors and found one of the 820uF capacitors was open circuit.  There was no visible damage on the capacitor (no leaks or bulging).

The TV worked fine after the repair

I was given just power supply board to repair which had one bulged capacitor.  I replaced all four capacitors that were the same brand.  Values were

• 1000uF / 25V (x2)
• 2200uF / 10V – bulged
• 220uF / 25V

After replacement, the owner indicated the media player was fixed.

Other model numbers:  LN32C540 , LN32C540F2D, LN32C540XZC

This TV would go through the process of turning on but there was no backlight nor picture.  The front led would flash a few times and then go out.

All voltages tested good coming from the power supply but the main board did not appear to be sending the BL_ON (backlight on) signal.  When I disconnected the cable between the power supply and main board, the backlight came on.

Researching on badcaps, the main board appeared to require replacement.  The part number was 96-14917A.  I was able to find only one used board on ebay with part BN96-15158A.  According to Shopjimmy, the board was one of many direct substitutes.

With the new board installed, the TV powered up with a picture.

Since the capacitors are all crappy Samwa, I proactively replaced them.  Values for BN44-00338B are as follows.

CM858, CM859 – 1000uF/25V
CM853, CM854, CB851 – 2200uF/10V
CM851, CM852 – 1000uF/35V

CM808 – 18nF/630VDC polypropylene capacitor is also a common failure.  Digikey substitute part is 495-7139-ND.

Other model numbers: LN32A450C1D and LN32A450C1DXZC

This TV uses a BN44-00214A (Dongyang MK32P5B) power supply board.  Schematic available here.  Opening the back of the TV, I found one bulged capacitor CM858  which I replaced.  The TV still had no power so when I checked the main fuse,  it was blown.  I replaced it with an 8A I had available.  I plugged the TV in a second time but this time I created some sparks.  A jumper by the big filter cap had blown apart along with the leg of one capacitor beside it.  The main filter cap had also bulged.  Researching the board number on badcaps found this board has an issue with the glue used to cover pins .  The glue drys out over time and becomes conductive.  It is used to prevent dust accumulating at the legs of high voltage components which may ignite.   I scraped off all the glue on the board, repaired the jumper, replaced the filter cap with a used one from another board, and resoldered the damaged capacitor (tested good on my meter).  I found a 6.2A fuse from another board and plugged it in again.  The fuse blew again but no sparks.

I checked the bridge rectifier with my multimeter and found a short between the + and – output pins.  This was traced to a short on QP801S (600V/10A/N Ch FET).  I temporarily replaced it with a similar FET and the TV finally powered up.  The inrush current limiting resistor NT811S (5 ohm) was also cracked so I replaced it along with all the large electrolytic Samwa capacitors.

Here are the part numbers for Digikey

QP801S – FCPF11N60F-ND 600V 10A N-Channel FET
FP801S  – 507-1215-ND 6.2A/250VAC ceramic fuse
NT811S – 495-4466-ND – ICL resistor 5 ohm 6A

Electrolytic Capacitors

CM851, CM852, CM868 – 680uF/35V
CM856 – 470uF/25V
CM858 – 680uF/25V
CM861 – 3300uF/10V
CB852 – 2200uF/10V