Sharp LC-60SQ15U TV DPS-167CP - No power

[weaboth]

Comparto mi experiencia, mi pantalla solo tenia los voltajes de stand by de 5v. Y mostraba un parpadeo corto y uno largo, al final encontre los leds da{ados y errores en la memoria de la main. Y tarde mucho por que crei que era error de los circuitos pfc; ya que les faltaba alimentacion al de pfc y el ncp.

[68pishta]

I aquired this TV to attempt to fix. Found the R7900 open and D7950 diode shorted. Replaced both (5A diode only available) and this immediately popped IC7903 with a SNAP! Did the 5A diode cause this? There was nothing hooked to power board when it popped. I poked around some more and found D7904 looks to be shorted as well. I measured the pins on the T7901 and they all look good with no internal shorts across its individual windings. Where next? I saw where you can substitute a different style 5V regulator to the IC7903 with adding a resistor to one of the legs. I didnt check the SMD side for any damage, just a very quick repair of the 2 parts i initially found to be faulty.

[romasik]

Re: Sharp LC-60SQ15U TV DPS-167CP - No power

I desolder supervisor and D7950 nothing change ((

[romasik]

Re: Sharp LC-60SQ15U TV DPS-167CP - No power

Is that the right resistor wattage R7900? And you double checked that diode D7950 was installed right?

yes all check, resitor 2.2 ohm 0,5W, diode 100V 5A installed right.

[dskall]

Re: Sharp LC-60SQ15U TV DPS-167CP - No power

Hello, please help me i have same problem on my Sharp Aquos 60LC635E No 5V power, tv dead . Blown R7900 and short D7950 . I changed it, than blown R7900 again . D7950 ok. I change IC7903 and cap on 5 leg 50V 47u and R7900 never blown again but 5V not( I do not know what to do . On big two cap 315V, on 5 leg IC7903 9V this very low for start A6069H . Datasheet say min 13V.

Please Help me. board power supply dps-162KP B RUNTKA932WJQZ

Is that the right resistor wattage R7900? And you double checked that diode D7950 was installed right?

[dskall]

Re: Sharp LC-60SQ15U TV DPS-167CP - No power

With STR-A6000. Strike that

[romasik]

Re: Sharp LC-60SQ15U TV DPS-167CP - No power

Have you compared all pin voltages with datasheet?

with datasheet suervisor?

[dskall]

Re: Sharp LC-60SQ15U TV DPS-167CP - No power

Have you compared all pin voltages with datasheet?

[romasik]

Re: Sharp LC-60SQ15U TV DPS-167CP - No power

.

Hello Does it make sense to desolder the supervisor? Or can I just remove the resistors on pins 1 and 3 supervisor? And try desolder D7950?

[romasik]

Re: Sharp LC-60SQ15U TV DPS-167CP - No power

What do you have in place for D7950? Maybe disconnect whatever is in there and see if the vcc comes up.
The ic's startup cell IS providing the initial 9volts, (at low current) so there can't be anything on that vcc line killing the voltage or you wouldn't have 9v. something is keeping the ic from oscillating.

On place D7950 i soldered SSL510 (SB5100 not yet in store)

[R_J]

Re: Sharp LC-60SQ15U TV DPS-167CP - No power

What do you have in place for D7950? Maybe disconnect whatever is in there and see if the vcc comes up.
The ic's startup cell IS providing the initial 9volts, (at low current) so there can't be anything on that vcc line killing the voltage or you wouldn't have 9v. something is keeping the ic from oscillating.

[romasik]

Re: Sharp LC-60SQ15U TV DPS-167CP - No power

Here is the block diagram of the ic I have no idea why you have 0 volts on pin4
Is R7918 (0Ω) open?
Are these NEW ic's or used?

Seller say these NEW, and say on 5 pin should be 15V for start IC and there will be no voltage on the 4th contact until it starts IC , R7918 not open (0Ω)

Does it make sense to desolder the supervisor? Or can I just remove the resistors on pins 1 and 3? I read on other forums that it happens to be a common problem his of not give starting IC

[R_J]

Re: Sharp LC-60SQ15U TV DPS-167CP - No power

Here is the block diagram of the ic I have no idea why you have 0 volts on pin4
Is R7918 (0Ω) open?
Are these NEW ic's or used?

[romasik]

Re: Sharp LC-60SQ15U TV DPS-167CP - No power

This is why I asked you to isolate pin 4 of the ic and check the voltage on just the ic pin4, This would eliminate EVERYTHING else connected to the ic.

I check 0 Volts

[R_J]

Re: Sharp LC-60SQ15U TV DPS-167CP - No power

This is why I asked you to isolate pin 4 of the ic and check the voltage on just the ic pin4, This would eliminate EVERYTHING else connected to the ic.

[romasik]

Re: Sharp LC-60SQ15U TV DPS-167CP - No power

PC7904 is used to turn on Q7902 to supply vcc_on so it can be left out of circuit for now.
If you also remove pc7903 and D7908, pin 4 of ic7903 should be about 7volts, If it does not come up, try isolating just pin4 from the circuit trace, this will eliminate any other component on that line as well.

What can you say about the removal of the supervisor, maybe maybe that's the reason?

[romasik]

Re: Sharp LC-60SQ15U TV DPS-167CP - No power

Try like this.

read pm please

[lotas]

Re: Sharp LC-60SQ15U TV DPS-167CP - No power

Try like this.

[romasik]

Re: Sharp LC-60SQ15U TV DPS-167CP - No power

Remove this supervisor IC7902, it sometimes brings problems with starting (the power supply works without it).

Possible unsolder resistor on pin Vcc for off power supervisor? It's enough?

[romasik]

Re: Sharp LC-60SQ15U TV DPS-167CP - No power

PC7904 is used to turn on Q7902 to supply vcc_on so it can be left out of circuit for now.
If you also remove pc7903 and D7908, pin 4 of ic7903 should be about 7volts, If it does not come up, try isolating just pin4 from the circuit trace, this will eliminate any other component on that line as well.

I check without pin 4 0V, I bought another a6069h today and soldered it in, but nothing has changed on 4 pin 45mV on pin 5 9,5V