P&F (Philips) 55PFL6900/F7 Turns on 3seconds then Off

[Shock2cure]

2015 55PFL6900/F7 4K

Got this dumpster TV this morning while taking out the trash, couldn't believe there was a 55" in there with an intact display, ya know I had to haul it home
What's more amazing is it doesn't seem to be much wrong w/ it.
Plug it in to AC, get a relay click, hit power button, it all lights up nice....for about 3 seconds, then shuts off, then 5 seconds later the tos-link for optical audio LED light on main board goes out as well. (Telling me not a backlight issue, I at least unplugged back light power, it does the same thing) I'm going to check voltages here shortly (I got to go look at a potential Home Theater Job for a house @ 2pm) But I figured I'd stick this up now with some pics hoping maybe there's a case history issue or if somebody's dealt with this issue before?
BBL!!!

[Shock2cure]

Re: P&F (Philips) 55PFL6900/F7 Turns on 3seconds then Off

Here's what I got voltage wise from CN657 off PS board
see pic for pin out

pin5=3.3v stby
pin6=0v stby - 3.3v power On
Pin8=0v stby - 3.3v power on
Pin9=3.3v stby
Pin10=3.3v power on
Pin15=12.9 stdby - 21v Power On
pin16=12.9 stdby - 21v Power On
pin17=12.9 stdby - 21v Power On
Pin18=12.9 stdby - 21v Power On
pins 23,24,25,26 all same= 8v stby - 12.8 power on

PS: All Power-On voltages drop to 0 when SPDIF light goes out

[Shock2cure]

Re: P&F (Philips) 55PFL6900/F7 Turns on 3seconds then Off

I'm thinking it's a fakked main board, these huge heatsinks make me think it's a BGA lift failure
still not sure, don't have pinout voltages labeled nowhere nor a service manual

[Shock2cure]

Re: P&F (Philips) 55PFL6900/F7 Turns on 3seconds then Off

may try a BGA re-bake in my Hasbro Easy-bake oven,lolz... Got nothing to lose there...lolz

[RJARRRPCGP]

Re: P&F (Philips) 55PFL6900/F7 Turns on 3seconds then Off

may try a BGA re-bake in my Hasbro Easy-bake oven,lolz... Got nothing to lose there...lolz

That's known as the "oven trick", over at Overclockers.com, IIRC.

Seems to be very popular with video cards...

[Shock2cure]

Re: P&F (Philips) 55PFL6900/F7 Turns on 3seconds then Off

That's known as the "oven trick", over at Overclockers.com, IIRC.

Seems to be very popular with video cards...

ya, I resurrected a couple Nvidia GTX 8100's & a 9500 that way, just wish I was 100% sure this is the problem here, PS board seems to have all the right voltages, cant see nothing physically bad on this main board, those two huge heat sinks soldered clamped to the board tells me they had issues with that wonderful BGA solder technique here maybe

[Shock2cure]

Re: P&F (Philips) 55PFL6900/F7 Turns on 3seconds then Off

Tried the ez bake method today, actually, took off heat sinks and hit them with the heat gun ....to no avail, still does the same thing ;(

[R_J]

Re: P&F (Philips) 55PFL6900/F7 Turns on 3seconds then Off

I would suggest you have bad backlights, when you said you unpluged them and got the same result, that would indicate an open led string.
It looks like there are four seperate led strings in this panel. I would place your meter probes across each string and turn on the tv. the voltage should come up then drop lower, post the voltages of each string
CN1101 pins 1&2
CN1201 pins 1&2
CN1201 pins 3&4
CN1401 pins 1&2
You can measure each pin with ground as reference or measure across each pair of led's

[Shock2cure]

Re: P&F (Philips) 55PFL6900/F7 Turns on 3seconds then Off

I would suggest you have bad backlights, when you said you unpluged them and got the same result, that would indicate an open led string.
It looks like there are four seperate led strings in this panel. I would place your meter probes across each string and turn on the tv. the voltage should come up then drop lower, post the voltages of each string
CN1101 pins 1&2 43.5v
CN1201 pins 1&2 47.7v
CN1201 pins 3&4 33v
CN1401 pins 1&2 41v
You can measure each pin with ground as reference or measure across each pair of led's

Thanks,
see pic
CN1101 pins 1&2 43.5v
CN1201 pins 1&2 47.7v
CN1201 pins 3&4 33v
CN1401 pins 1&2 41v

[R_J]

Re: P&F (Philips) 55PFL6900/F7 Turns on 3seconds then Off

I would think they should all be close to the same voltage, this seems to indicate a problem with cn1201 3&4 diode string. Being that the voltage is low could indicate shorted leds in the string trigering an error.
By chance if you unplug cd1201 only do you get a flash of the backlight?

[Shock2cure]

Re: P&F (Philips) 55PFL6900/F7 Turns on 3seconds then Off

yes, unplugging CN1201 still gets leds lit + gives me 2 more seconds of LED time ..lol

[Shock2cure]

Re: P&F (Philips) 55PFL6900/F7 Turns on 3seconds then Off

well if its LEDS, this TV's still screwed, I have the worst record of removing the displays and breaking the sh*t out of them...bummer. Guess the Boards going on flEbay I reckon

[Shock2cure]

Re: P&F (Philips) 55PFL6900/F7 Turns on 3seconds then Off

well I rigged up a couple outside LED strips from another Set and plugged them into CN1101 & CN1401
I then took the end plugs from CN1101 & CN1401 and connected those into CN1201.... Hit power button and....see pics

Everything is staying on, R_J, you were spot on sir, bad/burnt LED array within the CN1201section....which normally I would rejoice, but as I stated, I have a 0% recovery when trying to replace LED's, I ALWAYS end up breaking the displays, I dunno if it's because I'm a bull taking these apart or simply cursed. But either way this one is still going to be broken because I'm not ruining my day when I break this 4K display trying to replace LEDS....lolz....
...bummer

[Shock2cure]

Re: P&F (Philips) 55PFL6900/F7 Turns on 3seconds then Off

Well after sitting here staring at this sipping the morning Joe, I ripped it down...can still sell the working boards after i probably kill this display glass...lolz

-First Picture-
There's a total of 8 strips, 4 w/ 7 LEDs, 4 w/ 6 LEDs,
layed out in 4 pairs of 2, (1 w/ 6 leds. 1 w/ 7 leds)
52 LED's total

CN1201 drives the middle two rows
CN1101 drives top roww
CN1401 drives the bottom row

-Second Picture-
Red stars indicate the burnout LEDs
So 8 out of 52 are shot, 5 of them are connected to CN1201, so I see why the voltage was way off
I'm going to see if I got these LED's already, good chance I do,
still knowing I'm probably going to crack the helloutta this display putting it back...lolz
.......Well nothing from nothing is still nothing I reckon
RIP Billy Preston

[Shock2cure]

Re: P&F (Philips) 55PFL6900/F7 Turns on 3seconds then Off

I got every LED strip known to man.....except these...it figures, lolz

[Shock2cure]

Re: P&F (Philips) 55PFL6900/F7 Turns on 3seconds then Off

anybody knows where I can get these LED strips (not jimmys high dollar shop) drop me a PM, fleBays got squat, amazon's iffy, ali babba or whatever its called is scary,
thanks in advance

[R_J]

Re: P&F (Philips) 55PFL6900/F7 Turns on 3seconds then Off

These might be them, check the part number on them, https://www.shopjimmy.com/catalogsea...q=UDULED0SM050
Or http://www.tvpartsguy.com/products/p...led0sm051.html
I think they are UDULED0SM050

[Andrew F. Ali]

Re: P&F (Philips) 55PFL6900/F7 Turns on 3seconds then Off

How did you move the glass display? probably you can get a pair of vacuum cups to help you replace the glass when you are ready to close her up. For larger screens like yours I use a pair of that carry 4 vacuum cups each. Sorry I don't have a pic to post of them.

[Keshenatech1]

Re: P&F (Philips) 55PFL6900/F7 Turns on 3seconds then Off

I've done a lot of LED strips on TV's up to 65" and haven't broken one yet. (knocks on wood lol). What I use is the front and back panels from an empty cereal box. 1st tape the ribbon cable boards to the top of the screen with masking tape being careful to not stress the ribbon cables. Masking tape is good because it removes easily and won't leave any sticky residue on the screen. Carefully work the cardboard sheets under the display glass and carefully slide all the way around to unstick any spots that may be stuck down. Then position them in the center of the top and bottom edge with only a couple inches sticking out. Then carefully lift it from underneath with the cardboard trying not to touch the bottom side with your bare hand. It helps to fold the cardboard about 2" from the edge then you can grab the edge of the screen with the fold. And usually when I do this, I have it sitting on the floor and put down an old beach towel next to it to set the glass on so I don't have far to go. The key is holding it top and bottom center, not the long way on the left and right side, or it will buckle in the middle and break just about every time. Take your time and go very slow. You don't want any sudden motion to make it bend, or even worse bump into something with it.
Btw I found this thread because I'm working on a Philips 55PFL4901 very similar model with the exact same symptom. When I get back to the shop tomorrow I'm going to measure the voltages on the individual LED arrays and suspect I'll find a similar issue.

[pick1e]

Re: P&F (Philips) 55PFL6900/F7 Turns on 3seconds then Off

Did you have any luck with this? I have one doing the same thing.