Insignia NS-L22Q-10A Dim back light

[gica69]

Re: Insignia NS-L22Q-10A Dim back light

Good news is I opened and fixed the ccfl put it back together then I heard the hissing noise and now no red light for power. Don't get the 5v or 12v. No power passed the thick line that goes to IC903 to C931.
Also IC903 only has 75v on the 2 legs toward the hot side. The other side is dead.

[gica69]

Re: Insignia NS-L22Q-10A Dim back light

OK the red light is back but no picture even with flash light, period. Weird at least the power board is sending power. I will have to test out some of the components that might have burned.

[budm]

Re: Insignia NS-L22Q-10A Dim back light

When you make the measurement in the Hot side, what did you use for the GND ref. for the meter?

"Good news is I opened and fixed the ccfl " What did you fix on the CCFL?

[gica69]

Re: Insignia NS-L22Q-10A Dim back light

CCFL wiring wasn't lighting up on one side, this is a 4(2+2) wire one CCFL bulb so when you plug it in on one side lights up that side, so I opened it and either the wire was somewhat disabled and while repositioning it and started to light up. So the repair was most likely just repositioning. Remember I I used an external inverter to test these wires.
Anyways as far as ground I used the little nuts that are on the back of the monitor and hold the boards into place.

[budm]

Re: Insignia NS-L22Q-10A Dim back light

That sounds to like typical failure of the soldering of the wires to the lamp wire ends. The wire should be properly soldered back on to the lamps ends, this is one of the common failure in the CCFL assembly.
When you make the measurement in the primary side of the circuit, you have to use the negative leg of the main filter cap as the Gnd ref. for the meter, the reading you got is not valid due to wrong Gnd point for meter.

[vinceroger69]

Re: Insignia NS-L22Q-10A Dim back light

i totally agree with budm regarding the broken wire on the end of the ccfl
budm too test the ccfl he was using a external invertor i posted a picture of his invertor transformer any idea of the winding layout primary/secondary etc he needs to test to prove his onboard invertor is ok.

[gica69]

Re: Insignia NS-L22Q-10A Dim back light

Can you point out where this filter cap(capacitor?) is located? Also I no longer get the "Please Wait" screen so no lights for 2 seconds. But I get the 12V and 5V again. I get no power to the jumpers toward the 4 CCFL connectors. But I get 13V at the 5 legs of the transformer between them.

Here's a picture of the ground I use clearly marked as GND
Also some of the caps measure something on the top there are 2 the measure 0 ore .1V could that mean something?

[vinceroger69]

Re: Insignia NS-L22Q-10A Dim back light

post 3 first picture large filter capacitor is laid on its side too the right of the mains plug socket one side of that capacitor has a negative line/mark so put black probe on the capacitor leg but only use this for measuring the primary side voltages (danger of high voltage so be really carefull) on the secondary side yes use a screw or the metal tv chassis as a ground to test the dc voltages. Have you used your invertor tester to make sure the lamps still light?

[gica69]

Re: Insignia NS-L22Q-10A Dim back light

OK I am back to the beginning of the thread my picture came back it's still dim but I can see the menu and have sound. So that is great. I have to fix the inverter side of it.
So I still need to fix the backlight issue.

[vinceroger69]

Re: Insignia NS-L22Q-10A Dim back light

do the backlights all work using your tester?

[gica69]

Re: Insignia NS-L22Q-10A Dim back light

Yes sir they do
Did you see the pictures above with the caps, some getting voltage on top some not? Also all the jumpers around the number 9(red marker) have 0 voltage.

[vinceroger69]

Re: Insignia NS-L22Q-10A Dim back light

so all of 4 of them light up thats good now we need to see why the invertor transformer on your psu is not powering them ive no idea what windings you need to check for shorts/open circuits etc maybe if budm/or more experienced member than me is online later he/they can look at the picture and advise us on which pin combinations to check.

[gica69]

Re: Insignia NS-L22Q-10A Dim back light

Weird how some of the caps have really high voltage on top, in the hundreds and the others are below 1V. Something wrong in the circuit. The 2 seconds of light from before is not there anymore, but the "Please Wait" screen is there just dim.

So just waiting for instructions from the pros.

[vinceroger69]

Re: Insignia NS-L22Q-10A Dim back light

retest all the voltages on the connector that goes to the main board.

[gica69]

Re: Insignia NS-L22Q-10A Dim back light

Thanks the problem is the CCFL light that was giving me problems went out completely on both sides, so with that in mind I don't think it's worth the trouble to go any further since I doubt I can find the actual light. The main board is fine, the LCD is fine even the power supply and inverter might be fine I think the problem was in the CCFL since it trigger a shut down if it doesn't work. This was a hobby project from the beginning. Thanks a lot for all the help.