sharp lc-55le653u

[CANAM13]

neighbor gave me this sharp tv when he moved, said it died. I plugged it in and it came on normally, then shut its self off in 5 mins. left unplugged for an hour and powered it back on, worked again for about an hour then shut its self off again. Now nothing, no power, no standby light- no power at all.
test top power lead from PS supply to main board. have 19v across 3 terminals that is correct, but do not have 5v ps on stand by. figured was PS board, bought a used board from ebay, installed, same syptoms with no power, no stand by 5v at main plug from ps to main board. both board don't show any bad caps or burnt solder point or parts.
what should be my next troubleshooting steps?? Hate to throw out this nice screen. any help is greatly appeciated!!

[dick_barton]

Re: sharp lc-55le653u

Well focused and sharp photo's of your circuit boards and how they interconnect. If you could give the voltages at the connector going to the main board and the pin name alongside (legend normally printed on the board). Power supply number. All a good start to fault finding.
Something similar to the chart below makes for easier reading.

[Andrew F. Ali]

Re: sharp lc-55le653u

On these SHARP TVs there is no 5V StBy voltage, the 19V that you are getting at plug-in is the StBy voltage. DO NOT connect the 19V StBy voltage to PS-ON to test the PSU, this will damage it. Your problem though is a Main Bd. issue.

[CANAM13]

Re: sharp lc-55le653u

Well focused and sharp photo's of your circuit boards and how they interconnect. If you could give the voltages at the connector going to the main board and the pin name alongside (legend normally printed on the board). Power supply number. All a good start to fault finding.
Something similar to the chart below makes for easier reading.

attached the photos of the boards. The legend for power off of the PS board is only printed on the PS.
10- DIM2
9- DIM1
8- BLU_ON
7- PS_ON
6- GND
5- GND
4- GND
3- 19V
2- 19V
1- 19V

I have 120acv coming in to PS board, with main fused above connection testing good.
As I stated, I have 19v across 1-3 at the PS and it continues to the main board when power cord is connected. No power/voltage anywhere else through that connector. no bulging caps or burnt parts that I can see.
next step??

[budm]

Re: sharp lc-55le653u

So the main board is getting the 19V for it to run but it is not sending any control Voltages on pin 7 ~10 at all, ZERO Volt as you report, so something is going on with the main board.