Samsung LN52A650A1FXZA dead, standby LED just flashes repeatedly

[kevinm34232]

Re: Samsung LN52A650A1FXZA dead, standby LED just flashes repeatedly

1k ohms, on the good and the bad board. You're talking about these 2 right?

[budm]

Re: Samsung LN52A650A1FXZA dead, standby LED just flashes repeatedly

If that 3.3V regulator output is the one that feeds the input of 1.8V regulator then the one you measure resistance between the output of one regulator to the input of another regulator then it cannot be 1K resistance between the two pins.
Need to find the schematic of that main board to find out where that 1.8V regultor gets its input Voltage from. May be start check the resistance between the input of that 1.8V regulator and output pins of other regulator to see which one shows < 1 Ohm.
You can try downloading these service manuals:

http://elektrotanya.com/?q=showresul...oria=&kat2=all

BTW, what is the designator number for that 1.8V REGULATOR IC? U???, IC?????

[budm]

Re: Samsung LN52A650A1FXZA dead, standby LED just flashes repeatedly

1k ohms, on the good and the bad board. You're talking about these 2 right?

Well, we are talking about that one that you indicated that the input Voltage is only 2.4V, so is that the one you have measured?

[kevinm34232]

Re: Samsung LN52A650A1FXZA dead, standby LED just flashes repeatedly

Yes the 3.3v regulator is IC901, 1.8v regulator is IC1103 and has 2.4v at input.

[kevinm34232]

Re: Samsung LN52A650A1FXZA dead, standby LED just flashes repeatedly

The input pin of IC1103 leads back to pin 3 of IC101 (MP1583DN)

http://www.monolithicpower.com/Deskt...ocument?id=238

NM I replaced this IC voltages normal but still same problem thanks for the help..

[budm]

Re: Samsung LN52A650A1FXZA dead, standby LED just flashes repeatedly

OK, so the input Voltage of 1.8V regulator IC1103 is not fed by the other 3.3V regulator IC901, the input comes from switching regulator generated by IC101.
Did you download the service manual? May be IC101 feedback circuit is the problem.