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Old 10-06-2011, 01:09 AM   #1
koerneka
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Default Insignia NS-LCD32 black screen, varying colored vertical lines

Hi all,

I recently dug out an Insignia 32" LCD that I have yet to be able to fix. I'd like to use it in my bedroom.

Here's what happens when you plug it in. Upon pressing the power button, the LED lights up green. The backlight comes on to a completely black display, with a couple of faint vertical lines.

After about 5 seconds, the colored vertical lines appear, and sometimes shift horizontally a few pixels, or change color. The timing seems to be consistent with a "No Signal" box showing up.

Further, invoking the menu or changing input sources via the side panel buttons causes some changes in the colored lines.

Also of note, the Power Supply board has no noticeable bulged caps. They are almost all "JH" brand. However, the board emits a high pitched, slightly varied squeal when powered on. When the TV is powered off, the squeal gets higher, drops down, and comes back up, in a repeating cycle. (Think of a racecar engine revving and shifting.) It sounds like it is coming from the large 450V cap, but I cannot tell for sure. Again, no capacitors appear bulged.

I have done as much research as I can find, and I am not sure if I should suspect the power supply or the TCON board first. I am inclined to believe that the functionality of the side panel buttons indicates an operational logic board, but of course I cannot say with 100% certainty.

I can post pictures upon request - let me know what you would like to see.

Thanks for any advice!!
Kyle-
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Old 10-06-2011, 05:07 AM   #2
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Default Re: Insignia NS-LCD32 black screen, varying colored vertical lines

Quote:
Originally Posted by koerneka View Post
I can post pictures upon request - let me know what you would like to see.
Pictures always help. See what PlainBill writes regarding picture composition

http://www.badcaps.net/forum/showpos...18&postcount=2

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Old 10-08-2011, 05:18 PM   #3
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Default Re: Insignia NS-LCD32 black screen, varying colored vertical lines

Okay, sorry it took a while, but here are the pics. Just moved and don't have my digital camera unpacked (or located), so I did the best I could with my cell phone. The first picture is looking at the whole TV from the back, the second is the PS, and the third is an example of the lines that appear on the screen when you press a menu button.

The lines aren't "dead pixel" lines - they move slightly and change color when a different menu button is pressed.
Attached Images
File Type: jpg IMG00061-20111008-1905.jpg (171.9 KB, 63 views)
File Type: jpg IMG00062-20111008-1905.jpg (230.9 KB, 61 views)
File Type: jpg IMG00065-20111008-1908.jpg (343.3 KB, 76 views)
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Old 10-09-2011, 09:26 AM   #4
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Default Re: Insignia NS-LCD32 black screen, varying colored vertical lines

I had fixed a few NS-LCD32/37 TVs. All of them are bad main unit. I prefer bad main unit. By the way, I only replace main unit. Now I still have some broken boards in home. 32 and 37 share the same board.

Quote:
Originally Posted by koerneka View Post
Okay, sorry it took a while, but here are the pics. Just moved and don't have my digital camera unpacked (or located), so I did the best I could with my cell phone. The first picture is looking at the whole TV from the back, the second is the PS, and the third is an example of the lines that appear on the screen when you press a menu button.

The lines aren't "dead pixel" lines - they move slightly and change color when a different menu button is pressed.

Last edited by sheen818; 10-09-2011 at 09:29 AM..
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Old 10-09-2011, 10:46 AM   #5
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Default Re: Insignia NS-LCD32 black screen, varying colored vertical lines

Thanks for the response. Are the symptoms on my TV consistent with the symptoms of the units you have repaired?
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Old 10-09-2011, 11:44 AM   #6
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Default Re: Insignia NS-LCD32 black screen, varying colored vertical lines

your pictures are not clear, but looks like same. the main unit is mounted on the white plastic shelf. but this main unit is expensive and hard to get it.

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Thanks for the response. Are the symptoms on my TV consistent with the symptoms of the units you have repaired?
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Old 10-10-2011, 02:51 PM   #7
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Default Re: Insignia NS-LCD32 black screen, varying colored vertical lines

Anyone have any insights into the squealing noise? I'm thinking about going ahead and doing a PS recap because of the noise, and also because it is the cheapest option to try going forward.

Alternatively, does anyone have any guesses as to what voltages to look for to determine if the PS is in fact good?

I really hate to walk this thing out to the dumpster, but I live in an apartment and don't have much "working" space, so I am getting closer to that alternative.

Thanks!!
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Old 10-10-2011, 04:21 PM   #8
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Default Re: Insignia NS-LCD32 black screen, varying colored vertical lines

Quote:
Originally Posted by koerneka View Post
Anyone have any insights into the squealing noise? I'm thinking about going ahead and doing a PS recap because of the noise, and also because it is the cheapest option to try going forward.

Alternatively, does anyone have any guesses as to what voltages to look for to determine if the PS is in fact good?

I really hate to walk this thing out to the dumpster, but I live in an apartment and don't have much "working" space, so I am getting closer to that alternative.

Thanks!!
Expect common voltages, like 5V, 12V etc. I would expect the PSU to be marked.

Instead of taking it to the dumpster, stick it up on craigslist or ebay.
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Old 10-10-2011, 05:09 PM   #9
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Default Re: Insignia NS-LCD32 black screen, varying colored vertical lines

D'oh. Found the markings on the underside of the board. Should I take pictures, or is measuring them pretty self explanatory? Also, should I measure with a load (TV on), or just the PS plugged into the wall but nothing else connected? The latter would be much easier but probably not correct? Not sure...
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Old 10-10-2011, 09:42 PM   #10
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Default Re: Insignia NS-LCD32 black screen, varying colored vertical lines

Quote:
Originally Posted by koerneka View Post
D'oh. Found the markings on the underside of the board. Should I take pictures, or is measuring them pretty self explanatory? Also, should I measure with a load (TV on), or just the PS plugged into the wall but nothing else connected? The latter would be much easier but probably not correct? Not sure...
TVs of this size usually have a dual power supply. The standby supply is on whenever the power cord is plugged in; the main supply is switched on by the main board. Thus, you must have the main board hooked up to get meaningful results.

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Old 10-11-2011, 01:09 PM   #11
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Default Re: Insignia NS-LCD32 black screen, varying colored vertical lines

Okay i purchased a DMM and attempted to test the voltages on the power supply. The multimeter came with no instructions or explanations what so ever, and although I have used one before, I haven't used anything with this many functions.

With the tv powered off, there were no significant voltages. I got readings of like, .4.

With the TV powered ON, i touched one probe to a GND point, and the TV instantly shut off. So, apparently I am doing something wrong =\. I can post some pictures in a little bit.
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Old 10-11-2011, 02:54 PM   #12
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Default Re: Insignia NS-LCD32 black screen, varying colored vertical lines

What range did you select? V, ohms, A or mA?
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Old 10-13-2011, 12:29 PM   #13
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Default Re: Insignia NS-LCD32 black screen, varying colored vertical lines

Spent some time with the DMM and got acquainted; the 5V, 9V, 12V, and 24V lines are all +/- .5V of their rated voltage. I guess now is the time to start swapping boards, unless someone has another suggestion?
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Old 10-13-2011, 01:09 PM   #14
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Default Re: Insignia NS-LCD32 black screen, varying colored vertical lines

Can you post a picture of the Tcon board? There are usually some fuses on those boards that can be tested.
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Old 10-13-2011, 01:21 PM   #15
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Default Re: Insignia NS-LCD32 black screen, varying colored vertical lines

Alright, I will look into that. The Tcon is covered by a metal shield, which "hooks" into the frame. From the looks of it, I will need to disassemble the entire frame to get that off.

One thing I just thought of - I haven't tried hooking up anything to the composite video input to check for sound. I think I will try that as well, because a Tcon problem wouldn't affect audio, correct?
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Old 10-13-2011, 01:29 PM   #16
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Default Re: Insignia NS-LCD32 black screen, varying colored vertical lines

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Originally Posted by koerneka View Post
Alright, I will look into that. The Tcon is covered by a metal shield, which "hooks" into the frame. From the looks of it, I will need to disassemble the entire frame to get that off.

One thing I just thought of - I haven't tried hooking up anything to the composite video input to check for sound. I think I will try that as well, because a Tcon problem wouldn't affect audio, correct?
Usually a bad Tcon would still give good audio, although there is a rare chance that if it is loading down one of the rails on the main board (due to a short or failure), it will cause problems with the audio.
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Old 10-14-2011, 01:11 AM   #17
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Default Re: Insignia NS-LCD32 black screen, varying colored vertical lines

Well, I found the user manual online, and this happens to be one of those TVs which uses an input menu vs. just switching inputs every time you press the button. However, not having a picture makes it difficult to determine what input to select.

The TV also has AV out (composite), so I attempted to connect this to my main Vizio LCD. Upon turning on the Insignia unit, the Vizio shows snow on its AV input for about one second, then goes back to the "No Signal." Pressing Input or Menu on the Insignia TV doesn't bring a picture back to my main LCD tv. I am going to try to source an analog TV or video monitor that won't "cut out" to no signal screens when there is no reliable input...

I am kind of stuck for a little bit, it seems, but I am determined to try to repair this television! Thanks for any further insight!
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Old 10-14-2011, 01:51 AM   #18
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Default Re: Insignia NS-LCD32 black screen, varying colored vertical lines

I've been searching for info on this very problem for months on and off...

Of course I stumbled across this thread a couple hours after showing up at home with a new television. Still, it would be nice to have a spare to do something with, so I'm following along.

I managed to fix a 42" Panasonic plasma a couple months ago for the cost of a $20 transistor. I'm hoping I can do the same here within reason.
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Old 10-14-2011, 03:50 AM   #19
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Default Re: Insignia NS-LCD32 black screen, varying colored vertical lines

Quote:
Originally Posted by koerneka View Post
Well, I found the user manual online, and this happens to be one of those TVs which uses an input menu vs. just switching inputs every time you press the button. However, not having a picture makes it difficult to determine what input to select.

The TV also has AV out (composite), so I attempted to connect this to my main Vizio LCD. Upon turning on the Insignia unit, the Vizio shows snow on its AV input for about one second, then goes back to the "No Signal." Pressing Input or Menu on the Insignia TV doesn't bring a picture back to my main LCD tv. I am going to try to source an analog TV or video monitor that won't "cut out" to no signal screens when there is no reliable input...

I am kind of stuck for a little bit, it seems, but I am determined to try to repair this television! Thanks for any further insight!
Well, this has worked for me on a plasma with a faulty z-sustain (i.e. very poor picture.)

- Plug in working video source to TV
- Press Input/Source button
- Press okay - Any sound/video?
- Press Input/Source button
- Press down arrow
- Press okay - Any sound/video?

Repeat the process several times until all combinations of input have been exhausted. The good news is most TVs will remember the last input when turned off.
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Old 10-15-2011, 07:34 PM   #20
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Default Re: Insignia NS-LCD32 black screen, varying colored vertical lines

No luck with the input buttons - the only buttons on the side of the TV are Chan ^/v, Vol >/<, Input, Menu, and Power.

Further, I removed the metal shields from the logic board - there are about 16 "Chang" capacitors and a few "JH" caps as well. None look visibly damaged. Looked for components marked with an "F" or that seemed like a fuse, but found none. I can try to post some pictures soon... Are Chang or JH caps known for failure?
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