Philips 47PFL4606 No Power Fuse Keeps Blowing

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  • dick_barton
    replied
    Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

    Those results don't seem right. C946 is connected to the Opto isolator (IC907) which has 4.7V across it. It can only get that voltage from D916/C916 which you say is at 0.7V

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  • trunks81
    replied
    Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

    Hello Budm

    1. On C946 i get 0.7V ?! seems low to me !
    2. Between pin 3 and 4 i get 4,7V
    3. Between pin 1 and 2 i get 0.85V
    4. C943 is 21.32uF and 1.05 ohm
    5. its really an other board and tv !

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  • budm
    replied
    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.

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  • trunks81
    replied
    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

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  • budm
    replied
    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.

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  • dick_barton
    replied
    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
    Last edited by dick_barton; 07-23-2020, 03:49 PM.

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  • trunks81
    replied
    Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

    its a SRF1060
    Attached Files
    Last edited by trunks81; 07-23-2020, 01:32 PM.

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  • dick_barton
    replied
    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.
    Last edited by dick_barton; 07-23-2020, 12:53 PM.

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  • trunks81
    replied
    Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

    Tested D917.. for both diodes the forward Voltage is 200mV
    Looks low to me ?
    Attached Files
    Last edited by trunks81; 07-23-2020, 11:26 AM.

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  • dick_barton
    replied
    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
    Last edited by dick_barton; 07-23-2020, 10:17 AM.

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  • trunks81
    replied
    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

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  • dick_barton
    replied
    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?

    Leave a comment:


  • trunks81
    replied
    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
    Attached Files
    Last edited by trunks81; 07-23-2020, 04:48 AM.

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  • budm
    replied
    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.
    Last edited by budm; 07-23-2020, 12:06 AM.

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  • trunks81
    replied
    Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

    Originally posted by trunks81
    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

    Leave a comment:


  • budm
    replied
    Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

    Originally posted by trunks81
    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.

    Leave a comment:


  • trunks81
    replied
    Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

    Originally posted by dick_barton
    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 !)
    Attached Files
    Last edited by trunks81; 07-22-2020, 11:37 PM.

    Leave a comment:


  • trunks81
    replied
    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
    Attached Files

    Leave a comment:


  • budm
    replied
    Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

    Originally posted by trunks81
    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?
    Last edited by budm; 07-22-2020, 05:19 PM.

    Leave a comment:


  • dick_barton
    replied
    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???

    Leave a comment:

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