Philips 42pfl5432d backlight

[ryan74]

Re: Philips 42pfl5432d backlight

yes im in usa
cap is:
Peloa 220uf 450v

tested 203uf on dmm

[tom66]

Re: Philips 42pfl5432d backlight

Did you check the startup cap? It's different to the main cap.

[ryan74]

Re: Philips 42pfl5432d backlight

not sure which one that is but all caps(except the big one) were replaced when i started working on this.

[budm]

Re: Philips 42pfl5432d backlight

I think the 325vdc on the cap is too low.
See the sch of the power supply.

[ryan74]

Re: Philips 42pfl5432d backlight

ill do my best. i have some trouble with schematics. i understand about 25% of what i see but i also get lost sometimes trying to trace or find things. not to mention theres still alot of components i dont know like sg(donut shaped with copper winding).

[ryan74]

Re: Philips 42pfl5432d backlight

schematic didnt help too much but it looked like the problem could be around BD901 or ic902

im about to give up on this tv and junk it just because i have over 6 hrs of reading and looking at schematics invested (and 1 headache) it hasnt helped because i have such a limited understanding of component lvl repair. everything i read leads me to bad caps or diods(fets). im not paying over $100 for a replacement power supply.

At this point i would consider sending it out for repair if anyone is interested.

Are the parts circled capacitors? do these test any different?

I want to check BD901(one of a few i havent tested yet) but it has 4pins and 2 are marked +-. im not sure if i test the usual way with black probe on pin1 then red on 2-3-4 and report all readings then continue with black probe on pin2, red on p1,3,4 and so on.

[selldoor]

Re: Philips 42pfl5432d backlight

Not sure about the caps - dont think you can test except perhaps for being short or open

The BD is the bridge rectifier if that was not working you would get no voltage on the big cap. Here is one way of testing

Pins 0 0 0 0
..... 1 2 3 4
Mains power OFF
Set your meter to measure 2000 ohms.

Place positive (red) probe on the + pin. 1 above
Place negative (black) probe on the ac pin 2 above.
Write down the result. ohms

Place positive (red) probe on the ac pin. 2 above
Place negative (black) probe on the + pin 1 above.
Write down the result ohms

Place positive (red) probe on the ac pin. 2 above
Place negative (black) probe on the ac pin 3 above.
Write down the result ohms

Place positive (red) probe on the ac pin. 3 above
Place negative (black) probe on the ac pin 2 above.
Write down the result ohms

Place positive (red) probe on the ac pin. 3 above
Place negative (black) probe on the - pin 4 above.
Write down the result ohms

Place positive (red) probe on the - pin. 4 above
Place negative (black) probe on the ac pin 3 above.
Write down the result. ohms

You can cut and past the above and write in your results

It is like a double diode

[ryan74]

Re: Philips 42pfl5432d backlight

i think my meter only has autorange

Pins 0 0 0 0
..... 1 2 3 4
Mains power OFF
Set your meter to measure 2000 ohms.

Place positive (red) probe on the + pin. 1 above
Place negative (black) probe on the ac pin 2 above.
Write down the result. ohms = 3.75mohm

Place positive (red) probe on the ac pin. 2 above
Place negative (black) probe on the + pin 1 above.
Write down the result ohms = .0L

Place positive (red) probe on the ac pin. 2 above
Place negative (black) probe on the ac pin 3 above.
Write down the result ohms = 37.21mohm

Place positive (red) probe on the ac pin. 3 above
Place negative (black) probe on the ac pin 2 above.
Write down the result ohms = 35.72mohm

Place positive (red) probe on the ac pin. 3 above
Place negative (black) probe on the - pin 4 above.
Write down the result ohms = 0.746mohm

Place positive (red) probe on the - pin. 4 above
Place negative (black) probe on the ac pin 3 above.
Write down the result. ohms = 37.52mohm

testing the same pins in diode mode i got:
p1-2 =.496
p2-1 = .0L
p2-3 = .0L
p3-2 = .0L
p3-4 = .477
p4-3 = .0L

[selldoor]

Re: Philips 42pfl5432d backlight

Yes it is ok

[ryan74]

Re: Philips 42pfl5432d backlight

at this point im lost.
no idea what to look at now.
i havent located the big cap on schematics, i must be blind...lol

[ryan74]

Re: Philips 42pfl5432d backlight

D901
STTH8L06FP
GK2E9 VU
CHN 725

black probe on p1
p1-2 = 6.95mohms
black probe on p2
p2-1 = 0.L

i also tested in diode mode
p1-2 = 0.439v
p2-1 = .0L


im not sure how to test FB903, FB904, FB905
they look like diodes but no grey line

also theres resistors R969,R970,R971 on the bottom of board.
should i test these and how

i read ic902 on the back could cause problems but not sure how to test it either.

[ryan74]

Re: Philips 42pfl5432d backlight

If I can't figure it out this week I may have to send it here.
I can't find anything cheaper.

http://www.tvparts4less.com/philips-...e-service.html

[selldoor]

Re: Philips 42pfl5432d backlight

FBxxx are ferrite beads you jsut need to test for continuity
Resistors - you check on ohms - need to lift one end for accuracy /continuity
I dont know how to test IC - if you get the part number off it you might find a datasheet which would help

[ryan74]

Re: Philips 42pfl5432d backlight

I think I fixed it. Backlights turn on now.
I Think someone attempted to repair it before.
I found a bad trace on bottom of board after I went and bought a magnifying lamp.
After repairing it the backlights stay on.
I'm sooo happy I don't have to send it out.

Thanks for the help. At least I learned something.

[tom66]

Re: Philips 42pfl5432d backlight

Great job!

[selldoor]

Re: Philips 42pfl5432d backlight

Well done! - I usually spot that sort of thing but as you never posted pictures of the bottom sides it would be kind of difficult to see

[Dgtech]

Re: Philips 42pfl5432d backlight

I just got offered to buy this same model tv today but i got 3 sets in my shop now that I am working on plus I'm running low on cash till I sell one. LOL Good job!!!

[Dgtech]

Re: Philips 42pfl5432d backlight

Well, I just picked up the set today. I hope it's the usual suspects. The guy had this for years and he just now had the problem.

[tom66]

Re: Philips 42pfl5432d backlight

The guy had this for years and he just now had the problem.

I never believe people who say that.

[Dgtech]

Re: Philips 42pfl5432d backlight

All I did so far is plug it in to see what it does and it doesn't even show any difference between plugged in and not plugged in. Like I said before, I'm expecting this to be the usual four blown caps and maybe a diode or two. I won't get into this one till Saturday.