32 samsung lcd will not turn on just blinks 5 times

[GusShadow]

Re: 32 samsung lcd will not turn on just blinks 5 times

Recently I faced the same problem, with one Samsung TV with HANARO-2 power supply, and I would like to contribute a little bit for anyone else facing the same symptoms.

The TV had sound but no picture.
With the power supply disconnected from CPU board, the backlight illuminates for a second and then turned off.

By using the tip of mr. budm above, that said when the RP823 is removed the backlight and TV is working.
I checked a bit closer the circuitry, and I have remove the J867, this jumper connecting the RP823 with the FAN7530 IC [UP801S], this is much easier to remove.
I take a measure with a volt meter from the side of RP823 and earth the negative lead of CP809. I measure about 13V, I measure again with J867 in place, and now the meter indication is 0V.

So no VCC power for the FAN7530 and also no VCC power for the LM393 [UB802] comparator, and finally no INV_UVLO signal.

I checked the components and soldering of them, as follows [RP823], [UB802] Pin 8, [QB801], [ZB801], [DB802], [RB815], [PC802S], [DM802] , [RM890], [TM801S] transformer pin 5 and 6, there is a cold soldering that make the backlight not to working when the FAN7530 is connected. After the resoldering, the power supply is worked as it should be.

[ricosavy]

Re: 32 samsung lcd will not turn on just blinks 5 times

I accidently touched two pins on icb801s and looks like it blow resistor rb805 which is a fusible on schematic part number is 10j2w.color codes are brown,black,black,gold,white.i thinking it is a 10 0hm 2watt resistor but i am not sure.

[budm]

Re: 32 samsung lcd will not turn on just blinks 5 times

10 Ohms, J= 5%, 2W.

[ricosavy]

Re: 32 samsung lcd will not turn on just blinks 5 times

FW20A10R0JA Found this from mouser i think this will work.

[budm]

Re: 32 samsung lcd will not turn on just blinks 5 times

That should be fine, it is fusible resistor. Hopefully nothing else is damaged.

[ricosavy]

Re: 32 samsung lcd will not turn on just blinks 5 times

It is i think my pfc got damaged i replaced it but still would not work.I found this fusible resistor had blown.I will replace it when it arrives and test it also will replace 8 pin chip that i touched two pins on. I think it is ok but i will replace it when i get it.I believe it is the pwm that feeds the pfc.

[ricosavy]

Re: 32 samsung lcd will not turn on just blinks 5 times

I put in the fusible resistor measure at main cap i am getting 380 volts.I am still not getting backlights.also i check the ps on voltage it is at .8 volts i touch front power button i get no change.i jumpered the ps-on with 5volts to see if it would come on nothing just power light was on.Any ideas what else to check.

[ricosavy]

Re: 32 samsung lcd will not turn on just blinks 5 times

I did notice i was getting 12.1 volts where i am suppose to be getting 13v on connector going from power supply to main

[budm]

Re: 32 samsung lcd will not turn on just blinks 5 times

"I put in the fusible resistor measure at main cap i am getting 380 volts." That means the PS_ON must be present otherwise you will not have this boosted Voltage on the main filter cap, so I am sure what you are seeing at the PS_ON pin since PFC is working, also when you jump the 5V and PS_ON did you remove the wire going back to the main board?

[ricosavy]

Re: 32 samsung lcd will not turn on just blinks 5 times

Yes i did i removed the wire going back to main board to avoid feedback.i removed the jumper put the wire back in the connector.if disconnect main board i will get backlight.

[budm]

Re: 32 samsung lcd will not turn on just blinks 5 times

"if disconnect main board i will get backlight." That means the power supply and the backlights inverter is working.
Then the problem is on the main board that keeps the PS_ON stuck off.
So right we are back to the original condition at the start of the thread, main board problem.

[ricosavy]

Re: 32 samsung lcd will not turn on just blinks 5 times

I removed rp823 it reads 1.6 million ohms

[budm]

Re: 32 samsung lcd will not turn on just blinks 5 times

I removed rp823 it reads 1.6 million ohms

Where is this part?

[budm]

Re: 32 samsung lcd will not turn on just blinks 5 times

OK, I see that now, it is in the PFC Voltage sensing if the PFC boosted Voltage gets too high, it is 1.5Meg Ohms resistor, it is OK.
Right now the power supply is not the problem since the backlights do come on.

[ricosavy]

Re: 32 samsung lcd will not turn on just blinks 5 times

Why am i getting 12.1v where it says i am suppose to be getting 13v

[budm]

Re: 32 samsung lcd will not turn on just blinks 5 times

It is not tightly regulated power supply and it does not have to be since it is used for the Audio power amplifiers which does not required regulated Voltage to work.

[ricosavy]

Re: 32 samsung lcd will not turn on just blinks 5 times

I well at least we know i have a bad main board for some reason it is not supplying ps-on signal.i will try to trouble shoot it it is hard since there is no diagrams available for the main board and all the regulator seem to be working.there is only on chip with heat sink maybe i need to put some hot air on it see if it has any effect on main board.

[ricosavy]

Re: 32 samsung lcd will not turn on just blinks 5 times

It seems like lot people have same problem with this model.

[robwigglezz]

Re: 32 samsung lcd will not turn on just blinks 5 times

I was hoping that after 4 hours of reading I could have bought a 2 dollar part and been done with this TV.

Mine will randomly power on and function like normal if I pull the power plug from the back and plug it back in. (Maybe it's something simple, but I couldn't find anything similar)

I get 12.24v for all 13v pins and 5.24 for all 5v pins. Same results connected or disconnected from the other board.

[ricosavy]

Re: 32 samsung lcd will not turn on just blinks 5 times

There got be fix for motherboard there is people out there offering repair service