when i turn on, Philliips TV is not on

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  • Nish
    replied
    Re: when i turn on, Philliips TV is not on

    Is there anything I can do with it?

    Leave a comment:


  • Nish
    replied
    Re: when i turn on, Philliips TV is not on

    Originally posted by R_J
    The only voltage that points to a line is the 350v, That tells be that the pfc circuit and IC801 is working. The 16.24 seems to be the vcc supply, so that is correct. Is the 1.1 volts for pin 4 or pin5 of IC601?
    I have no idea where you measured the 87.2
    Looks like the IC601 circuit is not working, check the resistance of R618(15Ω), R617(51Ω) and R620(51Ω) and [R52 1](15Ω) If they are ok. Check the voltage on pins 11,14 & 15, Also is there any voltage on D601 cathode?

    I looked closer at the connections on T601, The connections on pins 1 & 2 don't look that good, Remove the old solder, clean up the trace and rivet and resolder them
    Here I have attached images with voltage
    Attached Files

    Leave a comment:


  • R_J
    replied
    Re: when i turn on, Philliips TV is not on

    The only voltage that points to a line is the 350v, That tells be that the pfc circuit and IC801 is working. The 16.24 seems to be the vcc supply, so that is correct. Is the 1.1 volts for pin 4 or pin5 of IC601?
    I have no idea where you measured the 87.2
    Looks like the IC601 circuit is not working, check the resistance of R618(15Ω), R617(51Ω) and R620(51Ω) and [R52 1](15Ω) If they are ok. Check the voltage on pins 11,14 & 15, Also is there any voltage on D601 cathode?

    I looked closer at the connections on T601, The connections on pins 1 & 2 don't look that good, Remove the old solder, clean up the trace and rivet and resolder them
    Last edited by R_J; 02-14-2020, 04:17 PM.

    Leave a comment:


  • Nish
    replied
    Re: when i turn on, Philliips TV is not on

    Is there anything I can check please?

    Leave a comment:


  • Nish
    replied
    Re: when i turn on, Philliips TV is not on

    Originally posted by R_J
    I was going by what you reported earlier in post# 143 and post#141 That is why I suspected the regulator, so it IS working ok.

    So you should now have PANEL+24V and P-ON+12V

    Ok sorry about that. I mislead you.


    No I do not have PANEL+24V and P-ON+12V at the connector.

    I have attached the picture of voltage now.
    Attached Files

    Leave a comment:


  • R_J
    replied
    Re: when i turn on, Philliips TV is not on

    Originally posted by Nish
    Should be the regulator IC902 is not functioning.


    But the IC902 pins are reading the below voltage.

    IC902
    Pin1 = 2.527v
    Pin2 = 19.19v
    Pin3 = 0v (gnd)
    Pin4 = 16.24v (output)
    Pin5 = 1.29v
    Pin6 = 0v (gnd)

    Is this IC not working? I am confuse.
    I was going by what you reported earlier in post# 143
    Output voltage of IC902 = 0.053v and goes to 0v right away.
    and post#141
    No voltage at output of IC902
    That is why I suspected the regulator, so it IS working ok.

    So you should now have PANEL+24V and P-ON+12V
    Last edited by R_J; 02-12-2020, 02:25 PM.

    Leave a comment:


  • Nish
    replied
    Re: when i turn on, Philliips TV is not on

    Originally posted by R_J
    That is correct. So if the INPUT has (19v) and the enable pin is high (18.5v) and the OUTPUT is 0 volts, (and the output line is not shorted to ground) what could be wrong.
    Should be the regulator IC902 is not functioning.


    But the IC902 pins are reading the below voltage.

    IC902
    Pin1 = 2.527v
    Pin2 = 19.19v
    Pin3 = 0v (gnd)
    Pin4 = 16.24v (output)
    Pin5 = 1.29v
    Pin6 = 0v (gnd)

    Is this IC not working? I am confuse.

    Leave a comment:


  • R_J
    replied
    Re: when i turn on, Philliips TV is not on

    Originally posted by Nish
    To supply voltage to IC801 and IC601. That's what I think.
    That is correct. So if the INPUT has (19v) and the enable pin is high (18.5v) and the OUTPUT is 0 volts, (and the output line is not shorted to ground) what could be wrong.

    Leave a comment:


  • Nish
    replied
    Re: when i turn on, Philliips TV is not on

    Originally posted by R_J
    Replace the regulator ic! The chances of that 10K resistor being bad is next to imposible.

    Again: Why do you think they have the regulator ic902 in this circuit?
    To supply voltage to IC801 and IC601. That's what I think.

    Leave a comment:


  • R_J
    replied
    Re: when i turn on, Philliips TV is not on

    Originally posted by Nish
    What should I do?
    Replace the regulator ic! The chances of that 10K resistor being bad is next to imposible.

    Again: Why do you think they have the regulator ic902 in this circuit?
    Last edited by R_J; 02-12-2020, 12:27 PM.

    Leave a comment:


  • Nish
    replied
    Re: when i turn on, Philliips TV is not on

    What should I do?

    Leave a comment:


  • Nish
    replied
    Re: when i turn on, Philliips TV is not on

    When I measure resistance, I did not get resistance. I thought bad resistor.

    Leave a comment:


  • R_J
    replied
    Re: when i turn on, Philliips TV is not on

    What is the point of replacing R818? Why do you think they have the regulator ic in this circuit?
    Last edited by R_J; 02-12-2020, 10:59 AM.

    Leave a comment:


  • Nish
    replied
    Re: when i turn on, Philliips TV is not on

    IC801 pin12 = 16.18v
    IC601 pin12 = 16.24v
    Q802 =0.659v
    Q800 = 0v

    I will replace R818 and see
    Attached Files

    Leave a comment:


  • R_J
    replied
    Re: when i turn on, Philliips TV is not on

    IC601 provides about 17v internally. This is a low current voltage and needs to be suplemented by IC902 for the ic to work.
    IC902 supplies the VCC voltage for IC801, pin12 and IC601, pin12 and also turns on Q802, which turns on Q800, which tells both IC801 and IC601 to start.

    I suspect if you replace the regulator ic, the power supply could be close to being fixed.
    Last edited by R_J; 02-11-2020, 05:12 PM.

    Leave a comment:


  • Nish
    replied
    Re: when i turn on, Philliips TV is not on

    IC902

    Pin4 = 16.42
    Pin5 = 1.27


    IC601 PIN12= 16.24

    Leave a comment:


  • R_J
    replied
    Re: when i turn on, Philliips TV is not on

    You can order them from China. They seem to be a custom part number but are likely made by Texas Instruments, and might be a TPS7A4501DCQR or TL1963ADCQR I have not tried any of these substitutes.
    Last edited by R_J; 02-08-2020, 06:12 PM.

    Leave a comment:


  • Nish
    replied
    Re: when i turn on, Philliips TV is not on

    I try to buy the regulator. I couldn't find this ic. I have attached the picture.
    Attached Files

    Leave a comment:


  • R_J
    replied
    Re: when i turn on, Philliips TV is not on

    Looks like the regulator is bad, It should output around 15~17v when ENable is high.

    Leave a comment:


  • Nish
    replied
    Re: when i turn on, Philliips TV is not on

    Before install 1k resistor
    PC902
    Pin4 = 16.22
    Pin3 = 15.55
    C906 = 16.20

    After 1k resistor install
    PC902
    Pin4 = 19
    Pin3 = 18.55
    C906 = 19

    Output voltage of IC902 = 0.053v and goes to 0v right away.

    Leave a comment:

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