Philips 42" TV 42PFL3603D/F7 clicks but No LCD Backlight

[jason123]

Hi folks,
I'm suspecting the actual CCFL or EFL being bad, just not sure how to test, but would like to confirm.

TV clicks upon plugging in AC. When I press the PWR ON button, clicks again.
LED on the Main board comes on green (Assuming some diagnostics), Blue LED on the TCON comes on also when I turn the TV on, but turns off about 30 seconds later.

3V3 ST is on (3.26 V)
Standy 3.3 V (off) when I press power button goes to 0.16 V
12Vssb is 11.75 V (on), 0.18 V (0ff)
+12Voud is 13.8V (on) ~ 0V off
-12Voud is -12.4 V (On) ~0V off

INV-on is 3.00 V (on), 0.115 (off)

Seems that it's in order from voltages standpoint. No bulging caps
I don't have a high voltage source to test the CCFL / EFL

[dick_barton]

Re: Philips 42" TV 42PFL3603D/F7 clicks but No LCD Backlight

Can you check the value and ESR of C700

[jason123]

Re: Philips 42" TV 42PFL3603D/F7 clicks but No LCD Backlight

Can you check the value and ESR of C700

~40 miliOhm

[dick_barton]

Re: Philips 42" TV 42PFL3603D/F7 clicks but No LCD Backlight

Have you got the 24V supply?

[jason123]

Re: Philips 42" TV 42PFL3603D/F7 clicks but No LCD Backlight

Yes 23.4v. Though nothing (connector) connects to it

[budm]

Re: Philips 42" TV 42PFL3603D/F7 clicks but No LCD Backlight

If you turn on the TV in the dark room, do you see the backlights even flash on for seconds?
Not all lamps will be all bad at the same time, the good lamps should still come on then if the circuit detects any bad lamp/lamps the inverter circuit will shutdown.

[tvtimmy]

Re: Philips 42" TV 42PFL3603D/F7 clicks but No LCD Backlight

Look under the inverter transformer for bad solder joints, these are notorious for them.
Touch them all up while you have the power supply out.

[jason123]

Re: Philips 42" TV 42PFL3603D/F7 clicks but No LCD Backlight

If you turn on the TV in the dark room, do you see the backlights even flash on for seconds?
Not all lamps will be all bad at the same time, the good lamps should still come on then if the circuit detects any bad lamp/lamps the inverter circuit will shutdown.

No light at all from the panel.

[jason123]

Re: Philips 42" TV 42PFL3603D/F7 clicks but No LCD Backlight

Look under the inverter transformer for bad solder joints, these are notorious for them.
Touch them all up while you have the power supply out.

Looks fairly clean. Touched up the solder.. no change

[R_J]

Re: Philips 42" TV 42PFL3603D/F7 clicks but No LCD Backlight

Have you checked the inverter distribution board, I don't see it in your picture, follow the high voltage cables from the power supply inverter to the inverter boards

[jason123]

Re: Philips 42" TV 42PFL3603D/F7 clicks but No LCD Backlight

I am assuming these distribution boards are inside the panel...haven't opened it yet

[jason123]

Re: Philips 42" TV 42PFL3603D/F7 clicks but No LCD Backlight

One ccfl completely disconnected. Let's see if that does it

[jason123]

Re: Philips 42" TV 42PFL3603D/F7 clicks but No LCD Backlight

Not it!

[R_J]

Re: Philips 42" TV 42PFL3603D/F7 clicks but No LCD Backlight

Do they try to light? How are all the other connections to the lamps?

[jason123]

Re: Philips 42" TV 42PFL3603D/F7 clicks but No LCD Backlight

I went through all and solder them all. They don't try to light up at all

[jason123]

Re: Philips 42" TV 42PFL3603D/F7 clicks but No LCD Backlight

I guess it's got to be power supply.. though I can't verify.. Time for the dump

[R_J]

Re: Philips 42" TV 42PFL3603D/F7 clicks but No LCD Backlight

Do you have the BL_ON_OFF voltage on CN7, pin-5? Check the voltages for U401, pin 20 should be +12v; pin 21/22 +5v

[nomoresonys]

Re: Philips 42" TV 42PFL3603D/F7 clicks but No LCD Backlight

I'd give it a good try at fixing, Philips usually has a very good picture quality.

[nomoresonys]

Re: Philips 42" TV 42PFL3603D/F7 clicks but No LCD Backlight

Did you check the fuse on the inverter board?

[ReeceyBurger123]

Re: Philips 42" TV 42PFL3603D/F7 clicks but No LCD Backlight

I’ve had cold solder joints on the inverter and bad CCFL connections on this model and the 47” UK version.