Samsung LN46B530P7N no picture

[Sobotka]

I was given the tv by a neighbor who was going to throw it out. I was thinking I could just replace a few bad caps, but the caps look fine. No bulging or leaking. When I plug the tv in it makes the melody start up tune, then blinks 5 times and the red light goes out. When I press the power button the start up tune plays again and the red light stays on solid, just no picture. Just wanted a few ideas of where to begin troubleshooting. Thanks!

[budm]

Re: Samsung LN46B530P7N no picture

You need to upload good clear pictures of the whole backside of the TV showing all the boards.
Power supply board P/N is BN44-?????
Did you see the backlights come on for seconds?
Do you have meter to be able to test the Voltages?

[nomoresonys]

Re: Samsung LN46B530P7N no picture

I always start where the cord comes into the tv, power supply board, see if you have all the expected voltages on the little legends/maps printed on there, use caution HIGH VOLTAGE can be DEADLY. check the videos right below.

[Andrew F. Ali]

Re: Samsung LN46B530P7N no picture

You need to upload good clear pictures of the whole backside of the TV showing all the boards.
Power supply board P/N is BN44-?????
Did you see the backlights come on for seconds?
Do you have meter to be able to test the Voltages?

I think more than likely there would be Power coming in as you hear the jingle on attempted start-up, so you could leave that out and not waste time measuring from the plug. Follow what budm is advising and post the photos as requested.

[Sobotka]

Re: Samsung LN46B530P7N no picture

Sorry I didn't upload pics earlier. Here's what I got. Forgive me if I got some of the nomenclature wrong. I plan to check voltage later this afternoon.

[Sobotka]

Re: Samsung LN46B530P7N no picture

There's no backlight flicker. I have a multimeter, but don't know with certainty which points to check on the DC side of the board. I can read the schematic where the main board plugs into the power board, and where the power board sends to the backlight inverter. For instance the 5th pin says det_5v on the "form main board" photo. I assume that pin should read 5v dc. I'm not so sure which pins to test on the others.

[freakaftr8]

Re: Samsung LN46B530P7N no picture

Shine a flashlight into the screen. Do you see anything on the screen after the jingle? Sometimes it's easy to look when you press the menu button.

Also you could try disconnecting the cable between the mainboard and the power supply then connect power and see if you have backlights.

[budm]

Re: Samsung LN46B530P7N no picture

Power supply-inverter combo board:
BN44-00202A

It does not have pull-up resistors for the self test function.
So lets see if we have PFC Boosted Voltage to run the inverter circuit or not, you need to set your DC Volt meter to the scale that can read Voltage over 400VDC, make sure to set the meter to DC V mode.

1) TV not connected to the outlet.
2) Check the resistance of the FUSE FM802, it should show less about 1 Ohm (that will depend on your meter probes resistance), if it does show about 1 Ohm then go to steps below.
3) You will be making DC Voltage measurement in the HOT DEADLY side of the circuit so you should at least plug the TV into the GFCI AC outlet.
4) Do not let your hands or your body touch anything on that power supply board.
5) Turn on the TV and then put the red probe of the meter to the Positive leg of cap CP810, Black probe on the Negative leg of the cap CP810.
6) Report the readings.

Pictures provided by shopjimmy.

[Sobotka]

Re: Samsung LN46B530P7N no picture

CP810 read 172v.

I had continuity at the fuse, but I don't think my probes measure resistance that low.

[Sobotka]

Re: Samsung LN46B530P7N no picture

I had done the flashlight test. No faint image seen.

I unplugged the small line from the main to the power board. When i plugged the tv in the jingle came on and the led standby button stayed on. When I pressed the power button, the jingle played, the led blinked 5 times and turned off, but there was a red light lit in the center of the main board.

[budm]

Re: Samsung LN46B530P7N no picture

OK so if the Voltage on the filter caps do not go up to around 380VDC, that means the PFC section is not working and since you do hear the chime up sound it means the power supply board is getting the PS-ON to turn on the power supply for the amplifiers to run.
More in-depth troubleshooting will be required, the backlights inverter circuits needs that boosted Voltage to work.

[maxvalutech]

Re: Samsung LN46B530P7N no picture

Did you do the high voltage reading budm requested with the front red light out on the set or with it on?

[Sobotka]

Re: Samsung LN46B530P7N no picture

I turned the power on after plugging in, and the red light was on.

Is this a power board issue? I'm not sure I have the expertise to do too much troubleshooting, although I'm certainly willing to try with guidance. Thanks for everyone's help. I talked to my neighbor, and he said the tv worked and had a good picture, but it would take up to 30 min to warm up and turn on. To be honest I haven't left it on long enough to see if it eventually comes to life.

[budm]

Re: Samsung LN46B530P7N no picture

I turned the power on after plugging in, and the red light was on.

Is this a power board issue? I'm not sure I have the expertise to do too much troubleshooting, although I'm certainly willing to try with guidance. Thanks for everyone's help. I talked to my neighbor, and he said the tv worked and had a good picture, but it would take up to 30 min to warm up and turn on. To be honest I haven't left it on long enough to see if it eventually comes to life.

You can try heating up the power supply board then power it up to see if it is OK or not, at this point, yes, you do have power supply problem due to no boosted Voltage.
It can be as simple as the filter cap for feeding the VCC to run the PFC IC, that is why I indicated that it will require more in-depth troubleshooting to get down to the faulty components.

[nomoresonys]

Re: Samsung LN46B530P7N no picture

http://www.shopjimmy.com/samsung-bn4...itors-only.htm Could try this repair kit, has 8 capacitors and 2 fuses, 10 bucks, watch a couple videos on soldering if you need to. or maybe diif could help.