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

[romasik]

Where should the voltage come from on the 5th leg A6069H?

[nomoresonys]

looks like it comes from c7901.

[romasik]

Originally Posted by nomoresonys

looks like it comes from c7901.

no c7901 leg 8 .

Here is a very similar sheme

sharp_runtka933wjn1_delta_dps-262cp-b_psu_sch.pdf

[nomoresonys]

I see, ok check c7906, r7909, r7919, d7904.

[nomoresonys]

make sure the resistors are the correct value and not open.

[nomoresonys]

Originally Posted by romasik

Where should the voltage come from on the 5th leg A6069H?

is this the vcc voltage?

[dskall]

Originally Posted by romasik

Where should the voltage come from on the 5th leg A6069H?

Use data sheet. Pin 7,8 are the startup voltage

[romasik]

Originally Posted by dskall

Use data sheet. Pin 7,8 are the startup voltage

Why??
Снимок.JPG

[romasik]

Originally Posted by dskall

use data sheet. Pin 7,8 are the startup voltage

STR-A6000H_SankenElectric.pdf

[romasik]

Originally Posted by nomoresonys

I see, ok check c7906, r7909, r7919, d7904.

everything is fine in my opinion

[nomoresonys]

Originally Posted by romasik

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

The voltage isn't high enough, just like you said here, the question is why, I can't figure it out but one of the pros knows I bet.

[dskall]

9.1 Startup Operation
Figure 9-1 shows the circuit around IC. Figure 9-2
shows the start up operation.
The IC incorporates the startup circuit. The circuit is
connected to D/ST pin. When D/ST pin voltage reaches
to Startup Circuit Operation Voltage VST(ON) = 38 V, the
startup circuit starts operation.
During the startup process, the constant current,
ISTARTUP = − 2.5 mA, charges C2 at VCC pin. When
VCC pin voltage increases to VCC(ON) = 15.3 V, the
control circuit starts operation

[romasik]

Originally Posted by dskall

9.1 Startup Operation
Figure 9-1 shows the circuit around IC. Figure 9-2
shows the start up operation.
The IC incorporates the startup circuit. The circuit is
connected to D/ST pin. When D/ST pin voltage reaches
to Startup Circuit Operation Voltage VST(ON) = 38 V, the
startup circuit starts operation.
During the startup process, the constant current,
ISTARTUP = − 2.5 mA, charges C2 at VCC pin. When
VCC pin voltage increases to VCC(ON) = 15.3 V, the
control circuit starts operation

between 3rd and 8th leg 300V

[romasik]

CAP c2 (C7907) i change but nothing changed

[dskall]

Check pin 5 diode, resistor and cap.

[romasik]

Originally Posted by dskall

Check pin 5 diode, resistor and cap.

i check, all ok

[dskall]

If all components off of pin5 are good. May have bad ic.

[romasik]

Originally Posted by dskall

If all components off of pin5 are good. May have bad ic.

So I replaced it with a new one.

My friend advises me to change IC7801, but I don’t understand how it can affect IC7903

[R_J]

What is the voltage on pin 4 of ic7903, this is the FB (feedback) voltage.
Is R7907 ok?
IC7801 will not effect ic7903. IC7801 is the pfc driver ic. and is not active in standby

[romasik]

Originally Posted by R_J

What is the voltage on pin 4 of ic7903, this is the FB (feedback) voltage.
Is R7907 ok?
IC7801 will not effect ic7903. IC7801 is the pfc driver ic. and is not active in standby

7907 check his ok, on 4 legs 40mV