Philips 47PFL4606 No Power Fuse Keeps Blowing

[trunks81]

Hello

Ive got one other 47PFL4606, only this one the fuse keeps blowing !
I allready replaced the next parts

BD901
D901
Q902
Q901

[budm]

Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

Same board as this one, right? No funny soldering going on?
https://www.badcaps.net/forum/showpo...63&postcount=1

[dick_barton]

Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

If you're blowing fuses then there a short or low resistance fault which youshould be able to find with your multimeter set to ohms.
Have you checked Q801 & Q802

Is this a second thread on the same set???

[budm]

Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

Hello

Ive got one other 47PFL4606, only this one the fuse keeps blowing !
I allready replaced the next parts

BD901 (Main bridge rectifier)
D901 (PFC diode)
Q902 (PFC MOSFET)
Q901(12V/24 SMPS MOSFET)

What are tested bad about those parts? What pin is shorted to what pin on those parts?
So the fuse is still blowing after you replace those parts?

[trunks81]

Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

At the moment only Q901 test between the D-S 1.25 OHM
Even afteri replaced it! When desoldered iam getting an normal reading

[trunks81]

Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

If you're blowing fuses then there a short or low resistance fault which youshould be able to find with your multimeter set to ohms.
Have you checked Q801 & Q802

Is this a second thread on the same set???

i forgot to check them they where the fault.. smps doesnt blow the fuses any more !

Edit smps stil doesnt has power to the M/B so i swapped out IC901 and IC902
After this R919 exploded and D901,Q902 measure very low ohms (these where replaced by me before !)

[budm]

Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

At the moment only Q901 test between the D-S 1.25 OHM
Even after i replaced it! When desoldered iam getting an normal reading

I am confused. Are you saying that when you test SMPS Q901 tested OK off the board, but tested shorted when it is on the board?
If that is the case you need to check the snubber cap C936 which is connected in parallel with S-D pins of Q901.

[trunks81]

Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

i forgot to check them they where the fault.. smps doesnt blow the fuses any more !

Edit smps stil doesnt has power to the M/B so i swapped out IC901 and IC902
After this R919 exploded and D901,Q902 measure very low ohms (these where replaced by me before !)

Checked C936 and it is oke ! No low ohmage and the meter measure 120uf in cicruit

[budm]

Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

I am confused, so when you first check
D901, Q901, Q902 the 3 original parts are all shorted and the main fuse was blown when you first check the TV out?
It sounds like you made it worst by throwing parts at it.

[trunks81]

Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

Oke

Resoldered the old parts back and replaced R919,D901,Q902
Now the smps doesnt explode or the fuse blows.

When i measure the 5V its only 2.7V, When i connect an 1K to S/B-5V iam getting 1.9V on the 5V
When checking the 12V its 0.040V and the 24V its 3V

Edit when i pull out C936 the short is gone ! But when i measure C936 in ohm it is not low, and capcitance is 139pf

[dick_barton]

Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

Edit when i pull out C936 the short is gone ! But when i measure C936 in ohm it is not low, and capcitance is 139pf

What resistance reading did you have?

What voltage do you now have across the two legs of C907?

[trunks81]

Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

Sorry i was wrong..

C936 my meter says its OL in ohms, last reading i touched something with my hands
C907 is 316VDC

[dick_barton]

Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

So you have lost your PFC voltage and worse still your +5VSTB standby voltage.
Since you have some voltage on the secondary supply for +5VSTB then IC905 must be working or attempting to work, I would check the components around IC905 and also D917

[trunks81]

Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

Tested D917.. for both diodes the forward Voltage is 200mV
Looks low to me ?

[dick_barton]

Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

Your tester gives it the OK so I would be satisfied with the reading.
Out of curiosity what is the diode part number.

[trunks81]

Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

its a SRF1060

[dick_barton]

Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

The data sheet shows the reverse voltage for the SRF1060 as 0.750V so the results do seem low. Use you multimeter set to diode mode and see what results you have.

If the 5VSTB is still not fully up I would check ZD914, D915, D916, ZD908, ZD907, ZD912

[budm]

Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

OP component tester only puts out low milliamp so the Vf reading will be low, see the Vf graph on page 4 of the spec sheet in post 16.
As you can see on page 2 of the spec sheet, Vf is 0.70V at test current of 5A.

[trunks81]

Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

Hello got the next reading on those diodes tested with the multimeter (UT-181A)

D917 = Both test 0.15V, And reverse OL

ZD914 = 0.51V and reverse OL
D915 = 0.51V and reverse OL
D916 = 0.50v Solderd out of pcb because on pcb got reading both ways
ZD908 = 0.50v Solderd out of pcb because on pcb got reading both ways
ZD907 = 0.70v Solderd out of pcb because on pcb got reading both ways
ZD912 = its not present on board

[budm]

Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

Just plug the power supply board by itself to the AC outlet without any 1K pull-up resistor.
1) What Voltage do you have on C946?
2) What Voltage do you have between the pin 3 and pin 4 (Photo Transistor side) of the OPTO IC907?
3) What Voltage do you have between the pin 1 and pin 2 (LED side) of the OPTO IC907?
4) Check C943 capacitance and ESR.
5) You post #10 "When i measure the 5V its only 2.7V, When i connect an 1K to S/B-5V iam getting 1.9V on the 5V" this one does not make sense, the Voltage should go up not down when pull-up resistor is connected, it is the same symptom for the same board in the your other thread for the same TV and board.