Badcaps Forums

Badcaps Forums (https://www.badcaps.net/forum/index.php)
-   Troubleshooting TVs and Video Sources (https://www.badcaps.net/forum/forumdisplay.php?f=31)
-   -   Samsung PN50B650S1F clicks on plug-in with flashing voltages (https://www.badcaps.net/forum/showthread.php?t=67700)

DXseekerMO 02-15-2018 02:56 PM

Samsung PN50B650S1F clicks on plug-in with flashing voltages
 
Hello everyone, my name is Steve and Iím new to the forum. My TV is a 2009 Samsung 50 inch plasma model no. PN50B650S1F. I looked here and other places on the net and I didnít see this specific issue, so before I throw parts at it I was hoping for some good advice. My experience level repairing TVís/electronics is best classified as ďbeginnerĒ. I can take good quality pictures/video if we need them.

Before service observations:

1) Upon plugging in the unit a click-click is heard, then about a second later another click-click. Television does not come on and intro chime is not heard. This continues as long as the unit is plugged in.
2) The red light on the front of the TV comes on when plugged in and remains on until the unit is unplugged regardless of noises heard.
3) The remote has no effect on the TV whatsoever, batteries checked.
4) There are no overheating smells or smoke coming from the unit
5) Outwardly the unit is clean and in excellent condition.

Removed back cover:

1) Unit was very dusty inside with dust bridges between the solder legs of many components. No evidence of water/liquid intrusion was found.
2) Upon plugging in the unit, the red light on the front of the TV illuminates continuously and a click-click is heard. The green LED number 2001 on the control board flashes twice in rapid succession then LED 2000 flashes on for about 1/20sec then 1/10sec. Another click-click is heard. This sequence lasts for about a second and repeats until the unit is unplugged.
3) Disconnected both X and Y boards from the power board. Unit still continues to cycle as above.
4) CAPS were visually inspected on the power board and have no outward signs of failure.
5) Board was inspected. No overtly hot spots were seen and all solder joints appear solid. The board has a slightly tan/brown appearance on the green printed circuit side near the long brown heat sink, on the lower voltage side of the power board. This heat sink looks like it has 7 MOSFETS on it.
6) The click-click is coming from a relay at location RL801S.
7) When the unit is plugged in, after the first click-click, standby voltage (spec 5.3v) comes up to 5.23v, Vs (208v) and Va (56v) reach specified voltage. After the second click-click the standby voltage immediately drops to zero while Vs and Va trail off slowly. This sequence repeats until the unit is unplugged.
8) One HDMI port on the input board is loose. A couple wires are broken and sticking out.

The troubleshooting guide I used says to replace the power board and re-test. My preference is not to replace parts blindly but test and troubleshoot as best I can then replace what is needed. I have a DVOM but nothing to check the CAPS accurately and I can unsolder/solder components on a board. I have a soldering iron but no other specialty soldering equipment.

Thanks everyone for any help or advice!

tvtimmy 02-15-2018 04:19 PM

Re: Samsung PN50B650S1F clicks on plug-in with flashing voltages
 
It could be a bad mainboard(where the hdmi ports are). I know the "A" series have a problem that is fixed with a 10 cent capacitor at C102 on the back of the main, but I dont know if yours has it. Somebody with more knowledge will step in.

freakaftr8 02-15-2018 05:26 PM

Re: Samsung PN50B650S1F clicks on plug-in with flashing voltages
 
This model is known for having faulty solder connections on the mosfet transistors that are located along the aluminum heat sinks on the power supply.

I would suggest re soldering all connections od components mounted to the aluminum heat syncs.

DXseekerMO 02-15-2018 07:04 PM

Re: Samsung PN50B650S1F clicks on plug-in with flashing voltages
 
Check the solder points and re-solder as needed or do them all? Re-flow or wick out and re-solder?

Speaking of those mosfets, I checked one at the center and right leg and it was zero ohms, shorted? I'd like to know for sure how to test the mosfets in-circuit if anyone could tell me how to do that?

freakaftr8 02-15-2018 07:33 PM

Re: Samsung PN50B650S1F clicks on plug-in with flashing voltages
 
0 Ω shorted? Is this component represented with a Q designator? I would say if it is a mosfet and not a diode and that would be your problem. If so you could replace the recommended parts or just go for a new power supply. Shoddy soldering usually if not caught in time we'll short mosfets.

DXseekerMO 02-15-2018 08:07 PM

Re: Samsung PN50B650S1F clicks on plug-in with flashing voltages
 
It is a diode. Just checked.

Do you think I should check the solder points and re-solder as needed or do them all? Should I re-flow or wick out and re-solder?

Do the defective solder joints have a circular bullseye crack around the mounting leg of the components? This board has several of them, but the legs don't move. They seem solidly mounted.

Thanks for the help!

tvtimmy 02-16-2018 05:21 AM

Re: Samsung PN50B650S1F clicks on plug-in with flashing voltages
 
A bullseye crack is bad. When the board heats up it expands and a short can happen. Just reflow everything that is mounted to a heatsink and whatever looks bad. Use lead solder, no need to wick it out.

DXseekerMO 02-16-2018 02:48 PM

Re: Samsung PN50B650S1F clicks on plug-in with flashing voltages
 
OK cook I will do just that. Thanks for the help everyone. So just heat the old solder and solder over it with new? It's probably a novice question but that best describes my experience level.

tvtimmy 02-16-2018 03:13 PM

Re: Samsung PN50B650S1F clicks on plug-in with flashing voltages
 
Yes.

DXseekerMO 02-16-2018 03:23 PM

Re: Samsung PN50B650S1F clicks on plug-in with flashing voltages
 
Thank you! Soldering iron is warming up.......

DXseekerMO 02-16-2018 05:26 PM

Re: Samsung PN50B650S1F clicks on plug-in with flashing voltages
 
It looks like the re-flow did not change anything.

DXseekerMO 02-17-2018 11:58 AM

Re: Samsung PN50B650S1F clicks on plug-in with flashing voltages
 
I also unplugged all the ribbon cables from the logic board. No change. Any ideas where to go next anyone? Thanks

tvtimmy 02-17-2018 12:44 PM

Re: Samsung PN50B650S1F clicks on plug-in with flashing voltages
 
Ok, plug everything back in. Then unplug the cable going to the control board from the mainboard and take a small clip or something to short pins 3 & 4 on control board. Plug in tv and look for test patterns on screen. If you have them the mainboard is bad.

tvtimmy 02-17-2018 12:47 PM

Re: Samsung PN50B650S1F clicks on plug-in with flashing voltages
 
1 Attachment(s)
The parts in red.

DXseekerMO 02-17-2018 01:14 PM

Re: Samsung PN50B650S1F clicks on plug-in with flashing voltages
 
Re-solder? The circles surround multiple components, are you talking about the ribbon connections? Thanks!

tvtimmy 02-17-2018 01:23 PM

Re: Samsung PN50B650S1F clicks on plug-in with flashing voltages
 
Circle on the left is the ribbon to unplug. Top circle has 4 pins. You have to short them together temporarily to test. You can use a piece of wire and wedge it in between pins 3 and 4.

DXseekerMO 02-17-2018 02:49 PM

Re: Samsung PN50B650S1F clicks on plug-in with flashing voltages
 
OK great I will try that and let you know what happens. Seems like we're testing the logic and input boards. I may have the names of those wrong?

tvtimmy 02-17-2018 02:55 PM

Re: Samsung PN50B650S1F clicks on plug-in with flashing voltages
 
mainboard has all the hdmi ports on it. Logic control board is the pic with the red circles.

DXseekerMO 02-17-2018 03:32 PM

Re: Samsung PN50B650S1F clicks on plug-in with flashing voltages
 
Ok cool. Thanks for straightening me out on that. Kinda need to know the right names for this stuff.

DXseekerMO 02-18-2018 12:10 AM

Re: Samsung PN50B650S1F clicks on plug-in with flashing voltages
 
Okay disconnected that ribbon cable, shorted pins 3 and 4 together with an alligator clip, plugged it in and no change. So are we going to disconnect a different cable, short the other two pins to check another board? Just guessin'


All times are GMT -6. The time now is 02:27 AM.

Powered by vBulletin ®
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.