Insignia 42" NS-L42Q-10A No Power/No Red/Blue LED

[SalemHermit]

I ran across this forum while looking for a solution for whatever seems to be wrong with my TV and found the following thread to be quite helpful.

https://www.badcaps.net/forum/showth...insignia+power

However, I'm not one to hijack other threads (especially for a first post) so I am starting this thread.

Like wiatery, I too have an Insignia NS-L42Q-10A that has no indication of power (other than a blue LED on the inside of the TV behind the back panel). The Red/Blue LED on the front does not come on when there is power.

I followed the troubleshooting steps provided by tom66 and these are the measurements I was able to get.

The fuse measured .5 ohms.
The NTC thermistor (the green one next to the fuse) measures at 4.1 ohms.
The AC Bridge on the back of the board measures 125.7 VAC.
The DC Bridge measures 167.9 VDC.

Now I tried measuring the volts of the big Rubycon capacitors, but I must not have done something right because I couldn't get anything near 6V to register on my multimeter.

I was also able to measure continuity of the big Rubycon capacitors, but only on the negative leads. Again, perhaps I did something wrong.

Any help would be greatly appreciated. Thank you!

[retiredcaps]

Re: Insignia 42" NS-L42Q-10A No Power/No Red/Blue LED

Now I tried measuring the volts of the big Rubycon capacitors, but I must not have done something right because I couldn't get anything near 6V to register on my multimeter.

For measuring the big caps, put your red probe on the positive leg and black probe on the negative leg of one cap. Then do the other cap afterwards.

Depending on your multimeter, you may have to put this on 1000V DC setting since this TV may have a PFC which means the big caps might go up to 400V DC. Needless to say, exercise caution around these big caps.

I use aligator clips on my probes so I can do the measurement hands free and minimize the risk for getting shocked.

[SalemHermit]

Re: Insignia 42" NS-L42Q-10A No Power/No Red/Blue LED

I'm not sure what I was doing wrong yesterday, but I was able to get a reading of .005 volts (5.9 mV) on each of the two big Rubycon capacitors. Does this sound right?

[selldoor]

Re: Insignia 42" NS-L42Q-10A No Power/No Red/Blue LED

I'm not sure what I was doing wrong yesterday, but I was able to get a reading of .005 volts (5.9 mV) on each of the two big Rubycon capacitors. Does this sound right?

No it should be hundred of volts - check your meter battery and try again.
I assume the power was on?
If still v low power off and check the resistance of the two resistors between the end of the heat sinks - perhaps R9209 and R9211 pictures not really clear enough.

[killian6pk]

Re: Insignia 42" NS-L42Q-10A No Power/No Red/Blue LED

Test a spare battery & make sure you are on DC volts. Also test one end of the fuse with the black probe on a screw and red probe on one end of fuse. This is with power on. Be careful lots of voltage in this area.

[SalemHermit]

Re: Insignia 42" NS-L42Q-10A No Power/No Red/Blue LED

Ok, with AC connected I was able to measure 168.5 VDC on both the large Rubycon capacitors. The two resistors between the ends of the two heat sinks (R9211 and R9208) measured .5 ohms and 1.7 ohms respectively.

I'm not sure what to check next.

[selldoor]

Re: Insignia 42" NS-L42Q-10A No Power/No Red/Blue LED

Can you do the test on the BIG caps again - you may need a helper or
aligator clips as retired caps suggested as I wany you to do the test as
you press the power button - I think it should jump the voltage up.
Care as high voltage.

Next with it all connected up and on check the voltages on the long connector
on the right hand side of the board (in your picture.)
Meter on 200v DC or autorangingDC Black probe on ground screw red probe on each pin in turn. ( Sometimes difficult to squeeze in don the side of the wire or some connectors you can see the pins in the side.

Post results as

Pin legend actual
1 24v 23.6v
2 12v 12.3v
and so on

[SalemHermit]

Re: Insignia 42" NS-L42Q-10A No Power/No Red/Blue LED

I got my fiance to hold the power down while I measured the voltage.

Both Rubycon caps measured 384v DC.

For the long connector (CN9102) I got the following measurements.

Pin...Legend.....Actual
3.....12v DC.....11.46v DC
4.....12v DC.....11.46v DC
8.....24v DC.....25.08v DC
9.....24v DC.....25.08v DC
11.....5v DC.......5.17v DC
12.....5v DC....5.17v DC

Unless I'm missing something, it looks like I'm getting all the power requirements that I should be getting from the power supply. Any suggestions?

[tom66]

Re: Insignia 42" NS-L42Q-10A No Power/No Red/Blue LED

Service manual available possibly matching your model

http://www.tgohome.com/ServiceManual...&Search=Submit

[crashp3]

Re: Insignia 42" NS-L42Q-10A No Power/No Red/Blue LED

It's a different service manual... just sent the correct one for your set (NS-L42Q-10A) to tom66... I'm sure it'll be on his site when he has a chance

While you're waiting to upload, attached is a snapshot of the flow chart for a "no power" scenario. The LED indicator referenced is the light on the front of the TV... not on the actual board itself

[selldoor]

Re: Insignia 42" NS-L42Q-10A No Power/No Red/Blue LED

I got my fiance to hold the power down while I measured the voltage.

Both Rubycon caps measured 384v DC.

For the long connector (CN9102) I got the following measurements.

Pin...Legend.....Actual
3.....12v DC.....11.46v DC
4.....12v DC.....11.46v DC
8.....24v DC.....25.08v DC
9.....24v DC.....25.08v DC
11.....5v DC.......5.17v DC
12.....5v DC....5.17v DC

Unless I'm missing something, it looks like I'm getting all the power requirements that I should be getting from the power supply. Any suggestions?

Just what I was thinking - Can you post a picture of your main?signals board front and back and a general view in the back of the set and any
other boards in there.

[SalemHermit]

Re: Insignia 42" NS-L42Q-10A No Power/No Red/Blue LED

Just what I was thinking - Can you post a picture of your main?signals board front and back and a general view in the back of the set and any
other boards in there.

Here you go. Hopefully this helps. I assume by main/signals board you meant the AV board?

[budm]

Re: Insignia 42" NS-L42Q-10A No Power/No Red/Blue LED

The PS_ON is working, the PFC is working. Is there a label 'BL_ON' on the power supply/Inverter board combo?

[selldoor]

Re: Insignia 42" NS-L42Q-10A No Power/No Red/Blue LED

OK in pic 3 there is a white fuse on the board just above the bottom connector.
Can you check it - meter on ohms - probe on each end should read the same as touching the probes together. Also can you check the voltage at each side of the fuse.

Next on the AV board there look to be 4 voltage regulators U 702 702 708 709
can you list the part numbers.
If they are voltage regulators you can test them:
Voltage regulators (U designation) can be bad. They can be shorted or output the incorrect voltage. The test described below only tests the former.

If you have a manual range multimeter, set it to 200 ohms (two hundred). You can test voltage regulators "in circuit" for shorts by (power off and unplugged)

a) black on pin 1- red on pin 2 - record ohms
b) black on pin 1- red on pin 3 - record ohms
c) black on pin 2- red on pin 3 - record ohms

If any ohm reading is less than 30 ohm you might have shorted voltage regulator. Remove from circuit and repeat the tests to verify.

[SalemHermit]

Re: Insignia 42" NS-L42Q-10A No Power/No Red/Blue LED

OK in pic 3 there is a white fuse on the board just above the bottom connector.
Can you check it - meter on ohms - probe on each end should read the same as touching the probes together. Also can you check the voltage at each side of the fuse.

The fuse in the 3rd pic (I have highlighted it in the attached image) measured at .5 ohms, which is what I got when touching the probes together on my multimeter. Also, The blue LED that is highlighted in my attached image fades after approx. 25 seconds and is gone. I'm not sure what the purpose of this board is, and if that is how the LED is supposed to work.

Next on the AV board there look to be 4 voltage regulators U 702 702 708 709
can you list the part numbers.
If they are voltage regulators you can test them:
Voltage regulators (U designation) can be bad. They can be shorted or output the incorrect voltage. The test described below only tests the former.

If you have a manual range multimeter, set it to 200 ohms (two hundred). You can test voltage regulators "in circuit" for shorts by (power off and unplugged)

a) black on pin 1- red on pin 2 - record ohms
b) black on pin 1- red on pin 3 - record ohms
c) black on pin 2- red on pin 3 - record ohms

If any ohm reading is less than 30 ohm you might have shorted voltage regulator. Remove from circuit and repeat the tests to verify.

Unfortunately, I don't have a manual range multimeter. I have a Craftsman 82139. Is there any other way to test the voltage regulators?

Here are the part numbers for the voltage regulators.
U702 1084-18PE 955E7R
U703 L401 G1084-33
U708 L331 G9084
U709 AZ1117D 50E1 943J74

U709 might also be AZ11170 50E1 943J74, I can't be sure. It was really hard to read it.



budm, I do not see anything labeled 'BL_ON', on the power supply/Inverter board combo.

[SalemHermit]

Re: Insignia 42" NS-L42Q-10A No Power/No Red/Blue LED

It's a different service manual... just sent the correct one for your set (NS-L42Q-10A) to tom66... I'm sure it'll be on his site when he has a chance

While you're waiting to upload, attached is a snapshot of the flow chart for a "no power" scenario. The LED indicator referenced is the light on the front of the TV... not on the actual board itself

Thanks for sending it to him. How were you able to find it? The only manuals I can find are the basic user manuals. I will see if I can't find these part labels on the board and test them, though I'm sure it would be easier to locate them with the pdf manual.

[crashp3]

Re: Insignia 42" NS-L42Q-10A No Power/No Red/Blue LED

Thanks for sending it to him. How were you able to find it? The only manuals I can find are the basic user manuals. I will see if I can't find these part labels on the board and test them, though I'm sure it would be easier to locate them with the pdf manual.

Good luck with the repairs.. I hope the manual helps

[selldoor]

Re: Insignia 42" NS-L42Q-10A No Power/No Red/Blue LED

Unfortunately, I don't have a manual range multimeter. I have a Is there any other way to test the voltage regulators?

Thats fine it just means that as you have an auto range you dont set it.
So check resistance as per page 11 of manual (Power off for resistance test)


With the power on can you check the voltage at the fuse on the av board (meter on VDC)

[SalemHermit]

Re: Insignia 42" NS-L42Q-10A No Power/No Red/Blue LED

Thats fine it just means that as you have an auto range you dont set it.
So check resistance as per page 11 of manual (Power off for resistance test)


With the power on can you check the voltage at the fuse on the av board (meter on VDC)

The fuse I have highlighted measures .5 ohms and 1.1 m V with power. I had the multimeter on DC and left it on auto tune. Just doesn't seem right to me.

[selldoor]

Re: Insignia 42" NS-L42Q-10A No Power/No Red/Blue LED

Ha ha Ha two wrongs dont make a right.

1 That is not a fuse

2 I told you the wrong board - I meant the Tcon

Can we try that again - Its a white fuse F1 125/2A.

Also - just to the left of your "fuse" there is a 4 wire connector and just to the left of that is a
black resistor with a 0 zero on it - can you check that for continuity as you would a fuse.