Samsung LN46B500P3F

[_N_]

Creeped around this place for odds and ends of info for long time.
Any help you guys can give me would be appreciated.
Ive used a DVM ( I own a few ), I can also do Hot air rework. Its a hobby.
I took psu Measurements while ON And results can be found on the pics.
I know this Tv was Tampered with by 2 other people who couldn't identify the problem before the owner let me have it

This tv has the following symptoms:

Tv plugged in has Red light, when power button on remote is pressed the samsung "On" chime can be heard.
Tv does not turn off until Remote is used and "Off" chime can be heard.
No Back light turns on whats so ever not even a flicker in a darkened room.
When I shine a flashlight at the screen I can see "Static Snow".

No bloated caps anywhere and pulled them ALL off and measured them with my Cap meter and all where within 10% of there stated rating.

I took pics of the boards If others are required, Just ask.

[budm]

Re: Samsung LN46B500P3F

Please measure the DCV right at the two legs of the MAIN FILTER CAPS in the primary side (450VDC caps laying on their sides), it should have >360VDC when TV is turned on.
The Voltage readings in this picture, is it after the power switched is activated?
https://www.badcaps.net/forum/attach...1&d=1425662978
It is missing required signals from the main board.
BTW, what is the P/N of the power supply/inverter board combo as printed on the barcode sticker? Picture is not clear enough to read the numbers.

[_N_]

Re: Samsung LN46B500P3F

151 Vdc on those 2 main caps.

Q:The Voltage readings in this picture, is it after the power switched is activated?
A: Those reading in the pics were while the set was "ON"

Q:supply/inverter board combo as printed on the barcode sticker
A:BN44-00265A Sec S/N :Cn08bn4400265ase38d9e1673 rf

[budm]

Re: Samsung LN46B500P3F

151 Vdc on those 2 main caps.

Q:The Voltage readings in this picture, is it after the power switched is activated?
A: Those reading in the pics were while the set was "ON"

Q:supply/inverter board combo as printed on the barcode sticker
A:BN44-00265A Sec S/N :Cn08bn4400265ase38d9e1673 rf

OK, the PFC Voltage booster is not working.
The main board is also not sending the INV ON/OFF (BL-ON), you are only getting 0.057V, same for the PWM Dimming signal of 0.42V.
The POW ON/OFF (PS-ON) is also very low, only 1.00V.
You should verify that your meter is OK or not.

http://www.shopjimmy.com/samsung-bn4...pply-unit.htm#

[_N_]

Re: Samsung LN46B500P3F

Ill re measure with another meter BrB

[_N_]

Re: Samsung LN46B500P3F

changed the batts in my meter and tried with a 2nd meter, the stated numbers in the pic i took are still the same.

[_N_]

Re: Samsung LN46B500P3F

tried with this,my best one.

[budm]

Re: Samsung LN46B500P3F

OK, BN44-00265B is about the same as 265A, the board has pull-up resistors for PS-ON and BL-ON so if you disconnect the cables between the main board and the power supply board you should then see the backlights come on when you plug the TV into the AC outlet if the power supply/inverter board is OK.
Did you inspect the board real well to make sure what done to the board before are done properly?

[_N_]

Re: Samsung LN46B500P3F

"disconnect the cables between the main board and the power supply board you should then see the backlights come on when you plug the TV into the AC outlet "

A: no lights at all.

Q: Did you inspect the board real well to make sure what done to the board before are done properly?"

Nothing looks horrible ,on the underside of the psu there's slight discoloration on the pcb mask around the 2 black transformers on the bottom left(of the pic , I took) and by a KIA393F BIPOLAR LINEAR INTEGRATED CIRCUIT : tested fine.

[budm]

Re: Samsung LN46B500P3F

"disconnect the cables between the main board and the power supply board you should then see the backlights come on when you plug the TV into the AC outlet "

A: no lights at all.

Q: Did you inspect the board real well to make sure what done to the board before are done properly?"

Nothing looks horrible ,on the underside of the psu there's slight discoloration on the pcb mask around the 2 black transformers on the bottom left(of the pic , I took) and by a KIA393F BIPOLAR LINEAR INTEGRATED CIRCUIT : tested fine.

OK then, you do have problem somewhere in this power supply/inverter board. So do you have >360VDC on the main cap when the wires are disconnected from the main board? If not then the PFC section will have to be repaired first but what bother me is that the main board is also not sending out the correct signals. i am sure you not want to repair the power supply board and find out that you also need the main board. I wonder if the TV was hit by the surge or lighting.

[_N_]

Re: Samsung LN46B500P3F

Q:"So do you have >360VDC on the main cap when the wires are disconnected from the main board?"
A: No I get 151VDC

I dont know what happen to it, it might have been a surge.
I have no idea it was sitting in some ones garage wrapped up.
I guess he didnt have the heart to throw it away.

I do notice on the scalar board the main board with Vga out hdmi ect.
The cpu has a heatsink and touching the top of it you cant leave your finger on that thing for more than 7 seconds, maybe it has a short somewhere and it appears to be a BGA chip.

Should I be seeing "snow" with a flashlight if the mainboard was bad?
Doesn't that control all the input signals attenna ect.
It could still be working but malfunctioning correct? so its not completely fried.

Im not against desoldering parts out and measuring whats needed.

[budm]

Re: Samsung LN46B500P3F

If you can see snow on the screen then it is not completely dead, so you will have to concentrate in the PFC circuit to get it running first, you can check the VCC pin and the GND pin of the PFC controller IC to see if it is present.

[_N_]

Re: Samsung LN46B500P3F

If you can see snow on the screen then it is not completely dead, so you will have to concentrate in the PFC circuit to get it running first, you can check the VCC pin and the GND pin of the PFC controller IC to see if it is present.

lx650 chip, ic801 , I imagine as per your schematic?
Remember Hobby Not Professional :}

[budm]

Re: Samsung LN46B500P3F

ICP801( 'P' for designator used in PC section), UCC28061
Remember that we are using 265B diagram for troubleshooting 265A board so not everything will match exactly.

[_N_]

Re: Samsung LN46B500P3F

ICP801( 'P' for designator used in PC section), UCC28061
Remember that we are using 265B diagram for troubleshooting 265A board so not everything will match exactly.

Tv is off I dont like smelling like beacon. ;}

leg 12 vcc to ground
in continuity mode gives 1800

is this what your looking for?
Or are we doing voltage checking for voltages present ?

[budm]

Re: Samsung LN46B500P3F

The Voltage on the VCC pin needs to be at least at the minimum Voltage requirement by the IC to run, I dis not look up the spec sheet of the IC to see what the minimum startup Voltage is yet.
Is the IC P/N UCC28061 printed on top of the IC?
BTW, you are working in the DEADLY PRIMARY side of the circuits so DO NOT TOUCH anything with your hands or body, I would plug the TV into the GFCI outlet for the minimum protection.

[budm]

Re: Samsung LN46B500P3F

OK, I look at the bottom side of the BN44-00265A and compared it to BN44-00265B, they are not even close to each other at all.
So the 265B diagram cannot be used. So it is going to be tough.

http://assets.shopjimmy.com/media/ca...65A-BOTTOM.jpg

http://assets.shopjimmy.com/media/ca...B-BOTTOM_1.jpg

[_N_]

Re: Samsung LN46B500P3F

"s the IC P/N UCC28061 printed on top of the IC?"

Nope not on my board the only thing in the pcb mask i can see that has 16 legs as
UCC28061 is the lx6503 chip http://pdf1.alldatasheet.com/datashe...MI/LX6503.html and thats not the same.

[_N_]

Re: Samsung LN46B500P3F

"OK, I look at the bottom side of the BN44-00265A and compared it to BN44-00265B, they are not even close to each other at all.
So the 265B diagram cannot be used. So it is going to be tough."

thats mine alright
http://assets.shopjimmy.com/media/ca...65A-BOTTOM.jpg
of coarse it is lol
couldn't be easy no sir.

[budm]

Re: Samsung LN46B500P3F

See picture.