2007 insignia ns-lcd32, backlight and sound, no picture

[tstokka]

good evening,

I've been lurking for a couple days, but cannot find the particular symptoms I'm having with my tv, let alone things I can check. When I turn the TV on it has a screen for a split second and then just the backlight. LED is green while it is on. I see no standby LED. After about 10 to 15 minutes it will shut off. I don't know the history of this TV, I just picked it up for free to tinker with.

Here is what I've checked:

Fuses on powersupply, good
all power going to logic board, 12,24,&5v all good
have 5 v going to the t-con board
I see no board discoloration, nor visible bad components

I'd like to know what else I should check, I'm leaning towards a T-con from everything I've read on this site.

[retiredcaps]

Re: 2007 insignia ns-lcd32, backlight and sound, no picture

When I turn the TV on it has a screen for a split second and then just the backlight.

1) If you hookup a source like a DVD player, do you get picture or sound?

2) If you shine a flashlight or look in a very dark room, do you see a picture with a DVD player connected?

3) Pictures are useful, but your resolution is too small for us to make out any detail. Try to get as close to 2000x2000 as possible.

4) We will also need a picture of the inverter board where all the ccfls plug into.

[tstokka]

Re: 2007 insignia ns-lcd32, backlight and sound, no picture

1) I tried a dvd player as well as my computer, I hit the input on the remote and waited 15 seconds, then hit it again. I did this a dozen times. I did this process while the cable, dvd(hdmi) and computer were hooked up. I don't know if i was switching inputs or just bringing up a menu.
2)I tried the flashlight and saw nothing.
3) sorry about the small pictures, I'll get better ones tonight as well as the inverter board.

Thanks for your help.

[retiredcaps]

Re: 2007 insignia ns-lcd32, backlight and sound, no picture

I'm leaning towards a T-con from everything I've read on this site.

1) Okay, there is a fuse on your t-con (in red). A good fuse should measure less than 1.0 ohms. Measure and report your findings.

2) There are 2 voltage regulators marked in yellow. What is the part number and DC voltages for each pin?

Report it like

U1
part # = AL117-33
pin 1 = 0.0
pin 2 = 3.3
pin 3 = 4.99

3) There is white glue holding down the connector. Try removing all the glue, cleaning it up with isopropyl alcohol and reseating the connector. That glue is there during the assembly process to hold it in place, but maybe the cable has shifted and the glue is no longer adhesive? Be careful as this could be a very fragile connector.

4) Also try reseating and cleaning the other two connector ends as well.

[tstokka]

Re: 2007 insignia ns-lcd32, backlight and sound, no picture

Ok, first off word of warning, while testing the voltage do not, I repeat DO NOT lay your forearm on the power supply!

I cleaned the connectors first, that glue was really stuck.

1) fuse 0.4 ohms

2) left on the picture
part # = 1117-3.3SJ
pin 1 = 0.0
pin 2 = 1.84
pin 3 = 5.02

RIGHT
part # = 1117-2.5SJ
pin 1 = 0.0
pin 2 = 2.49
pin 3 = 4.53

also when I reassembled to test the voltages, I noticed the back light turns on and shuts off right away, before it would stay on for 15 minutes.

[retiredcaps]

Re: 2007 insignia ns-lcd32, backlight and sound, no picture

Ok, first off word of warning, while testing the voltage do not, I repeat DO NOT lay your forearm on the power supply!

Yes, the heatsinks are likely live.

part # = 1117-3.3SJ
pin 1 = 0.0
pin 2 = 1.84
pin 3 = 5.02

The above is bad. The suffix -3.3 denotes the output voltage that should appear on pin 2.

The above part is widely available. Measure the size of the regulator to make sure you get the right size (i.e. package). It should be less than $1. Alternatively, if you have old pci boards laying around, you might find one on an board. These parts are widely used in almost everything.

[tstokka]

Re: 2007 insignia ns-lcd32, backlight and sound, no picture

I'm not very good at soldering, so I just bought a new t-con board. That regulator did the job! As for the back light not working after I put it back together to do the tests, I missed a 2 pin connector on the inverter board.

I'm going to hang on to the old board and play around with my soldering skills.

Thanks Retired for all your help!

[tstokka]

Re: 2007 insignia ns-lcd32, backlight and sound, no picture

Thanks again!

[belamex]

Re: 2007 insignia ns-lcd32, backlight and sound, no picture

I have the same issue. There are many types of 1117 2.5 and 1117 3.3 out there.. So which one should I get? What are the specs? I normally use ebay or mouser (Not affiliated).. But there are many different types. Which ones do I get?? Please advise.


I need to know:
1 Input Max Voltage:
2. Output Voltage
3. Dropout Voltage (Max)
4. Output Current
5.Load Regulation
6. Output Type " Fixed or adjustible?
7. Maximum Operating Temperature