Philips 55pfl5505d/f7 blinking light

[microvibe]

I have a Philips 55in LCD TV. When you plug it in it starts blinking the LED white light in front and then when the back lights come on the lights stop blinking but there's no picture turn the back light to go off and it starts blinking again between 8 and 14 blinks then go solid again when the back light to come back on just keeps on doing this. I think something to do with that protect3 but dont know where check

I have voltages

Cn4
24v= 24.6v
Protect3 .6v when blinking, .02v when backlights come on.
Bl-sw 3.23v
Bl adj .95v
Cn5
24= 24.6v
Cn2
12v= 12.3v
5.3v= 5.3v
Stby= 5.23v
Ps-on 3.1v
Bl-on 3.1v
Bl adj .95

[R_J]

Re: Philips 55pfl5505d/f7 blinking light

If your backlights are working, It is likely normal for the led to blink during startup. I would check if you have voltage going to the t-con board, check on both sides of the t-con fuse

[neilc6]

Re: Philips 55pfl5505d/f7 blinking light

Found your tv service manual online with quick google search. There should be troubleshooting flowchart, block diagrams and schematics with expected voltages.

https://www.electronica-pt.com/esque...-pl10.8-68774/

[microvibe]

Re: Philips 55pfl5505d/f7 blinking light

I have 12v on both sides fuse on tcon. Accirding to flow chart replace psu. Well thats useless. I csnt gind what the protect3 voltage reading should br

[R_J]

Re: Philips 55pfl5505d/f7 blinking light

Just to be clear, if you turn on the tv the backlights come on and stay on?

I'm not 100% sure but that protect3 line should come from the inverter board, and if there IS a backlight error (broken ccfl, bad fet/transformer etc.) that line would likely go to 3.1 volts shutting down the tv. The power supply and the inverter/backlights are working, so the fault is likely with the main board or t-con.
What are you using for a source? try pluging in a HDMI source and see if the tv finds it and gives you sound.

[microvibe]

Re: Philips 55pfl5505d/f7 blinking light

When u plug in the tv it starts blinking then backlights come on. They stay on for 3-5 seconds then off and its blinking again then come back on and cycle repeats. Never a picture. Would tcon cause main board to shut off backlights. I tried with tcon disconnected same thing

[CapLeaker]

Re: Philips 55pfl5505d/f7 blinking light

Did you check and compare the output windings of those little transformers on the inverter board? These have to be within 3% of each other to work. A bad transformer will run hotter. Also did you check the caps on that board?

[microvibe]

Re: Philips 55pfl5505d/f7 blinking light

Wouldnt video be produced before or same time the backlights come on. Backlights stay on few seconds never a logo or picture.

[CapLeaker]

Re: Philips 55pfl5505d/f7 blinking light

no, not necessarily, but you should see the menu if you shine a very strong flash light into the screen. Or you test the lvds with an oscilloscope and turn the menu on and off all the time.

[nomoresonys]

Re: Philips 55pfl5505d/f7 blinking light

With tv unplugged from power, because there can be over 1000 DEADLY volts on the ccfl side of the inverter board, take the shield off the inverter board, look it over for any obvious problems and check those 4 caps for bulging leaking etc.

[nomoresonys]

Re: Philips 55pfl5505d/f7 blinking light

Luckily those transformers are easier to test than some models.

[nomoresonys]

Re: Philips 55pfl5505d/f7 blinking light

Some transformer testing there, there's some better ones just a matter of finding them, didn't see any for your exact model, that testing is with tv UNPLUGGED from power: https://www.youtube.com/watch?v=lvBo3vetuGs

[nomoresonys]

Re: Philips 55pfl5505d/f7 blinking light

Here's one with more detail, it's not a philips but give you the gist: https://www.youtube.com/watch?v=oE6K4xBVweA

[microvibe]

Re: Philips 55pfl5505d/f7 blinking light

I have 8 of these transformers. If i am testing them right 5 out of the 8 have at least one secondary winding open. Is that even possible and backlights still come on? I know each tube was being lit up.

[R_J]

Re: Philips 55pfl5505d/f7 blinking light

If the transformers have the same numbers and the same windings for the secondaries, I will guess you are not checking them correctly. How are you testing them.

[microvibe]

Re: Philips 55pfl5505d/f7 blinking light

I tested them the way you show all secondary same reading, 2 transformers have shorted primary and 2 are open the rest are .594, secindarys were 1.643

[R_J]

Re: Philips 55pfl5505d/f7 blinking light

I would remove one of the transformers to confirm the configuration, I believe I was wrong on the primary connections. After looking at the whole inverter I believe it could be just the two center connections on the transformers are the primary winding.

[CapLeaker]

Re: Philips 55pfl5505d/f7 blinking light

were the secondaries all within 3%?

[microvibe]

Re: Philips 55pfl5505d/f7 blinking light

Secondaries were within 3% of each other.

[CapLeaker]

Re: Philips 55pfl5505d/f7 blinking light

Put this thing kind of back together, disconnect the main board from the PSU and force the PSU on. Use 1k resistors between STBY, over to PSon, BLon and maybe the DIM signal. Plug it in, the PSU should be fully on and the backlight too.