Riddled TV Repair Forum

gabryant · Joined: 01 Sep 2016 Posts: 9 Location: United States

A family member gave me a Samsung UN39FH5000FXZA (v. PF03) which is dead - no power, lights or anything. They were going to recycle it, but I thought I would give it a go first, and if no luck, then recycle it myself.

I did some research - the capacitors appear okay - no bulging or splitting on the tops.

The TV does not power on - no lights or anything. I took off the back and see three boards, a Main, T-Con and a Power board.

I really have no experience with testing volts and that sort of troubleshooting, so it seems like the easiest steps for me would be to replace the boards. And seeing as the TV didn't cost me anything to begin with, the prices to replace the boards aren't too bad - may $100 altogether.

I could replace each board individually as a process of elimination. Which board should I start with first, second and last? And If I replace all of the boards and still no luck are there any other steps that I could take to see if this TV is recoverable - or bound for the recycle heap?

Thanks for any help that you can give me.

Google

JTS1957 · Joined: 21 Jan 2009 Posts: 2395 Location: Far, Far Away

Google will show you the way to test volts.

See if A5V is present between JP813 and ground on the Power Supply/LED Driver board.

If present, unplug CNM803 and see if screen lights (and stays lit).

gabryant · Joined: 01 Sep 2016 Posts: 9 Location: United States

I did go pick up a cheap voltage ohm meter last night, so I'll give that a try. Thanks for the reply.

gabryant · Joined: 01 Sep 2016 Posts: 9 Location: United States

gabryant · Joined: 01 Sep 2016 Posts: 9 Location: United States

Finally checked the power board for 5V standby. I checked the CNM803 jack, which has the cable connecting to the Main board.

Pin #12 was marked A5V. That showed 0 V.

I also checked the rest of the pins on the CNM803 jack. It was kind of hard to get at all of the pins, I had to disconnect the cable to do so. All of the pins showed 0V. I grounded on one of the GND wires on the Power board AND again on the chassis just to make sure.

From the ShopJimmy video on Youtube, this is telling me that I should replace the Power board first.

https://www.youtube.com/watch?annotation_id=annotation_2477836281&feature=iv&src_vid=VmL9EVvY2ag&v=qxG3hmmvkJs

Given that I've done everything that I can, do you agree with that, or is there something else that I should do?

(Just to rule out one more thing, I also checked the electric cord with one of those electrical outlet testers - has the two prongs and the light that lights up to show the outlet has power. The electric cord is okay.)

Google

JTS1957 · Joined: 21 Jan 2009 Posts: 2395 Location: Far, Far Away

1) Re-read my corrected 1st post. BN44-00666A Power / LED Driver Board.
2) Voltages are measured with black lead at JP812. Meter set to measure DC Volts.
3) Voltage is measured with TV plugged into a live AC outlet.

In regards YouTube ... be sure the set being talked about is a reasonable 'match' to yours. Your set being 2013ish and YT video set being 2009 is a very wide gap. Things can and do sometimes change drastically in just one year.

I DO want you to have everything connected and secured with AC applied when Main to Power board cable is disconnected.

gabryant · Joined: 01 Sep 2016 Posts: 9 Location: United States

Went back and followed your revised steps. Still 0V with red lead on JP813 and black lead on JP812. TV was plugged in when tested. Board was screwed into chassis and all cables connected.

I used this multimeter:

The dial was set on "DCV 20". Just to make sure I was doing it right, I plugged the red lead into both the top and middle jacks, with the black lead on the bottom jack both times.

Thanks for the heads up on Youtube date. Didn't think to look at that.

gabryant · Joined: 01 Sep 2016 Posts: 9 Location: United States

I do follow what you are testing - JP813 is marked A5V (standby?) and JP812 is marked GND (ground).

There should be some power between those two regardless of whether the TV is on or off, right?

You do have the correct board: BN44-00666A / L40GF_DDY (PCB REV: 1.1)

JTS1957 · Joined: 21 Jan 2009 Posts: 2395 Location: Far, Far Away

There IS an 'edit' button at top right of each of your posts.

Meter = bottom two for everything except 10Amp DC current measurements.

Since NO all time (standby) 5V, I'd suggest starting by replacing the Power/LED Driver board.

If that fixes set, don't forget to reduce the back light LED intensity by at least 50%, more if you can. Compensate with "brightness" and "contrast" settings.

This is one of the Manufacturers that shipped sets with settings adjusted for the best picture (NOT the best setting for LED bulbs lifespan).

gabryant · Joined: 01 Sep 2016 Posts: 9 Location: United States

Yeah, the instructions are bad on the meter - says plug red lead into top. So I did check with the red in both top and middle jacks.

Okay, that's what I suspected, that the board is bad.

Most of the power replacement boards for sale are "new" i.e., pulled out of a TV with a cracked screen. Do you recommend those, or should I go for a "real new", i.e., never installed in anything board?