lg 47LB585V help to identify ic please

[jimbofz]

Hi this lg has a rediculously small 16 pin ic on mainboard cooking
causing brief flash of sby led then dead its the one next to a coil 2r2
reference ic2403 i cant make it out looks like:

5419
0rAA
A36X
this tv had bad b/l leds and i replaced all the strips with new
they tested fine with led tester ,ifound the b/l controller ic s/c bl0202b and q803 s/c these were replaced but leds just flashed on for one second .
to save time (big mistake) i ordered replacement psu from e bay
when fitted it caused the mainboard problem grrr!
now even my original psu wont start up
ive tried to find cct for main board i can only find psu cct
if someone can help me identify the ic or suggest why the rogue psu has caused the problem it would be a great help

the rogue psu is:EAX65423801(2.1)REV 2.0
the original psu is:EAX65423801(2.2)REV 2.1

[lotas]

ic2403 - TPS54319

[jimbofz]

Originally Posted by lotas

ic2403 - TPS54319

many thanks ,now i have somewhere to start ,
i suspect ,as it gets hot.
something external to it is drawing current through it

[lotas]

service manual

[jimbofz]

Originally Posted by lotas

service manual

thanks ,i have s/c on pins 1 and 2 to ground.
im going to try to replace ,removal no problem with s station but fitting new will be a chalenge,
im going to force on the psu without connecting main board and see if 3.3v supply is high ,do you think this could be the reason the ic failed?

[lotas]

If it exceeded more than 7v, then the IC could burn out.

[jimbofz]

not looking good .pin 10,11,and12 .the 1.5v o/p s/c
so protection zener zd2401 was never fitted
so any number of components could be s/c

[lotas]

1.5v for power supply of random access memory (DDR).

[dick_barton]

If you lift L2411 are pins 10, 11 & 12 still short and if not is the other end of L2411 showing the short.

[jimbofz]

Originally Posted by dick_barton

If you lift L2411 are pins 10, 11 & 12 still short and if not is the other end of L2411 showing the short.

thanks for joining in the party mr b
when L2411 Lifted it measures 240 ohm .so not short but still a bit lower than i would expect ,what do you think?

[dick_barton]

Are you saying L2411 has a resistance of 240 ohms or the output of the IC (1.5V ) to ground measured 240 ohms.
What is the resitance with the meter on one pad of L2411 to ground and again what is the reistance from the other pad of L2411 to ground both checked with L2411 lifted.
If the resistance of the IC2403, pIns 10, 11 & 12 is 240 ohms to ground then that would appear to be OK.

[jimbofz]

the o/p of the coil when lifted is 240 ohm to deck ie the 1,5v supply 240 ohm
the other side is dead short to deck i know the tps54319 is duff
but i would expect a much higher value on the 1.5v o/p side
the coil itself is fine very low ohms

[dick_barton]

The 240 ohm reading would appear to be fine and is not a high load on the 1.5V supply

[jimbofz]

ok thats reassuring .ive found a scrap pana main board with similar ic so im going to practice removing and refitting on this .what is interesting is on the pana main board the o/p pins 10,11,12 read 3.9k to deck
i know all ccts differ so best not to read into this too much ,
i think the board came from a pana TX-L 32C5B

[dick_barton]

You may well be correct. Just looking at the application note show there are two mosfets connected in totem pole so the 240 ohms could well mean that one of the internal mosets is damaged.
Good luck with your repair. Use plenty of flux with the solder and be patient.

[jimbofz]

Originally Posted by lotas

ic2403 - TPS54319

a question for lotas
do you know if:
0101
5173
is same device ?
ive found one on a panasonic tx-l32c5b main board

[lotas]

Originally Posted by jimbofz

a question for lotas
do you know if:
0101
5173
is same device ?
ive found one on a panasonic tx-l32c5b main board

"5173" - This is your G5173.
Check datasheets. Your family should be marked "54319".

[jimbofz]

wow thanks for quick reply
it looks the same BUT its o/p is: 1.8v not 1,5v
its markings are :0101
5173

[lotas]

Originally Posted by jimbofz

wow thanks for quick reply
it looks the same BUT its o/p is: 1.8v not 1,5v
its markings are :0101
5173

Their output voltage is set by a resistor divider.

[lotas]

To test the mainboard, you need to dismantle the TPS54319 and connect an external laboratory power supply (+) to the L2411 with 1.5V - 2A.