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Old 08-04-2010, 05:03 PM   #1
ajsemtb
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Default Insignia 32" LCD TV Model# NS-32LCD

Hello all. I have an Insignia (best buy brand) 32" LCD that has died... sort of... I have found forums about this tv doing this very thing, but I wanted to see if anyone here had any experience with this TV.

The red power light is on, and pressing the power button turns the red light "off" (a blue light should come one, but mine hasn't worked since I got it over a year ago) but the screen doesn't turn on. No audio either.

According to some other forums I've read, people have just replaced the power board (about a $50 part with shipping) but I would like to see if I can just repair the board I have first. However, I opened it up expecting to see bulged caps, and none are. Does anyone have experience with this problem or similar?

Thanks in advance
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Old 08-04-2010, 05:29 PM   #2
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Default Re: Insignia 32" LCD TV Model# NS-32LCD

Welcome.

What we need you to do first is to post clear pictures of the boards, front and back if possible. Post as attatchments (see "Manage Attatchments" on posting page).
What skill level are you at repairing? Some of these are simple, and some of em are more intense.
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Old 08-04-2010, 05:30 PM   #3
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Default Re: Insignia 32" LCD TV Model# NS-32LCD

Quote:
Originally Posted by ajsemtb View Post
Hello all. I have an Insignia (best buy brand) 32" LCD that has died... sort of... I have found forums about this tv doing this very thing, but I wanted to see if anyone here had any experience with this TV.

The red power light is on, and pressing the power button turns the red light "off" (a blue light should come one, but mine hasn't worked since I got it over a year ago) but the screen doesn't turn on. No audio either.

According to some other forums I've read, people have just replaced the power board (about a $50 part with shipping) but I would like to see if I can just repair the board I have first. However, I opened it up expecting to see bulged caps, and none are. Does anyone have experience with this problem or similar?

Thanks in advance
The obvious first step would be to check the output voltages of the power supply (assuming they are marked at the connectors). If the voltages are incorrect (or missing) it will be necessary to troubleshoot the power supply. With a little searching I found what claims to be the service manual for a similar model; the power supply is very basic.

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Old 08-04-2010, 09:37 PM   #4
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Default Re: Insignia 32" LCD TV Model# NS-32LCD

I would call my skill better than novice, but not by much.. LOL I have soldering skills, a work bench, a DMM (no capacitance checker though), and pick up things quick. I really enjoy tinkering and have fixed many things that people have dismissed as trash for fun. But also, just randomly changing parts without knowing if they work or not could be more costly in time and money than just buying a new part.

I am also working on a viewsonic VX910 monitor using the advice found on this site (thank PlainBill for your info on those from before.. VERY HELPFUL!!!) And I'm using that repair as my "trial" before I start to destroy, I mean repair my TV. XD Parts are in the mail for that and should be here tomorrow...

Back to the power supply. There are 3 different "sets" of connectors that send voltage. Set 1 has 5 "prongs" for 24 volts, the second 2 sets, the third 1 for 5v. The actual readings are: 24.3 or 24.4 for all and something close to 5v for the third. on the third set of pins, one says 5v, on GND, and the next "ON". So with no cable plugged into that plug, there were no readings on any of the 24V pins. So I plugged it in, pushed the power button, and got my readings. So, maybe its working? I dunno. I do know that this tv did have some kind of work done to it before I bought it, but I don't know what.
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Old 08-04-2010, 09:40 PM   #5
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Default Re: Insignia 32" LCD TV Model# NS-32LCD

Dang, I thought I had attached the pics, then I did the test and lost em...
Attached Images
File Type: jpg board bottom.jpg (567.9 KB, 236 views)
File Type: jpg board top.jpg (562.4 KB, 397 views)
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Old 08-05-2010, 11:49 AM   #6
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Default Re: Insignia 32" LCD TV Model# NS-32LCD

Yes, it certainly sounds like the power supply is working.

The rough design: The power supply contains TWO power supplies, a low current 'Standby' supply which is always on, and a main supply that is switched on and off. This switching is done by the 'standby processor' on the main board, which often also handles the signals from the remote and the control panel.

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Old 08-05-2010, 01:39 PM   #7
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Default Re: Insignia 32" LCD TV Model# NS-32LCD

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Originally Posted by ajsemtb View Post
The actual readings are: 24.3 or 24.4 for all and something close to 5v for the third. on the third set of pins, one says 5v, on GND, and the next "ON".
Were these readings taken with the logic board attached? Can you post a pic of the logic board (both sides)?
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Old 08-05-2010, 10:24 PM   #8
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Talking Re: Insignia 32" LCD TV Model# NS-32LCD

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Originally Posted by retiredcaps View Post
Were these readings taken with the logic board attached? Can you post a pic of the logic board (both sides)?
I'm sorry, I don't know what the logic board is, so I took pics of most of the boards...

The nothing was connected to the power supply EXCEPT the cord that PlainBill was talking about that had the low voltage/high voltage switch on it. That cord connected to "board 1" in my pics. I don't konw how or where it went after that. Somehow it made its way to the switch though...

After looking at these boards, nothing appears burnt or bulged (obviously any way...) A couple caps "could" be bulged or they could just be puffy compared to the X stamped in the top... Nothing obvious. >;F
Attached Images
File Type: jpg board 1 bottom.jpg (529.8 KB, 160 views)
File Type: jpg board 1 top.jpg (707.1 KB, 190 views)
File Type: jpg board 2 bottom.jpg (583.9 KB, 134 views)
File Type: jpg board 2 top.jpg (696.0 KB, 164 views)
File Type: jpg lcd open.jpg (696.2 KB, 231 views)
File Type: jpg vgi board.jpg (494.7 KB, 160 views)
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Old 08-05-2010, 10:36 PM   #9
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Default Re: Insignia 32" LCD TV Model# NS-32LCD

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Originally Posted by ajsemtb View Post
I'm sorry, I don't know what the logic board is, so I took pics of most of the boards...

The nothing was connected to the power supply EXCEPT the cord that PlainBill was talking about that had the low voltage/high voltage switch on it.
The logic board is the one marked 782 32FB18-690D.

The reason I am asking if anything else was attached to the power board when you took those readings is the voltages may not be stable when everything is hooked up (which I haven't resolved yet).

It is low probability, but I have a monitor that when the logic board is disconnected, the voltages on the power board are stable. With the logic board connected, my voltages drop to zero.

You may have the same issue, but I suggest rechecking the voltages with everything connected. Check the voltages on the other boards. So if the cable connector says 24V on the power board, check for 24V DC on the logic board.
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Old 08-06-2010, 01:35 AM   #10
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Default Re: Insignia 32" LCD TV Model# NS-32LCD

I would have to say that it is the secondary fuse marked FU502 on the power supply board if yours has one.I had an Insignia NS-27LCD I was working on that had the standby light,but wouldn't turn on.I bought a used power supply to try because at first I didn't see anything wrong with the original.Turned out I had to return it because after hooking it up,it wouldn't even show a standby light.After getting a working power supply board,the TV worked perfect.After looking at the original power supply I noticed a pink resistor looking component that was a little burnt on one end,that tested open on my meter.On the bottom of the board it is marked with a rectangle with a line through it.My guess is that was all that was wrong with the original power supply.I got the idea after reading online about Nintendo DS having bad SMD fuses causing them not to turn on.I also ended up testing one on an Akai LCT-2060 that wouldn't turn on,and that turned out to be the problem.I hope this helps.Thank You very much!
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Old 08-06-2010, 01:45 AM   #11
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Default Re: Insignia 32" LCD TV Model# NS-32LCD

Looking at the pictures,it looks like it is right above the top heatsink towards the right a little if you are looking at it with the main fuse in the bottom right hand corner.It looks like a rectangle with a line through it in the picture of the bottom of the board about an inch from the left side in the center.Thank You very much!
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Old 08-07-2010, 08:08 AM   #12
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Default Re: Insignia 32" LCD TV Model# NS-32LCD

Quote:
Originally Posted by 70JUDGE View Post
Looking at the pictures,it looks like it is right above the top heatsink towards the right a little if you are looking at it with the main fuse in the bottom right hand corner.It looks like a rectangle with a line through it in the picture of the bottom of the board about an inch from the left side in the center.Thank You very much!
Tyler
Thanks for the tip, but unfortunately, they both (I found FU502 and FU503) passed a continuity test and with an ohm check the were at 0.1 or 0.2.

Retired: I will check with everything hooked back up later today. It will take a bit of time, because each of those boards were in a seperate metal case, and it took some work to get them off. I just don't want anything to short by not having at least the bottom piece on.
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Old 08-07-2010, 09:11 AM   #13
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Default Re: Insignia 32" LCD TV Model# NS-32LCD

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Originally Posted by ajsemtb View Post
Retired: I will check with everything hooked back up later today.
Before you hook everything back up, wait for PlainBill's feedback.
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Old 08-07-2010, 03:04 PM   #14
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Default Re: Insignia 32" LCD TV Model# NS-32LCD

I'm afraid the most likely candidate for replacement is the processor card (the one with the big black heat sink in the middle).

Before jumping on that, however, I've marked up a couple of the pictures. Both the tuner and the processor cards have several voltage regulators. A failure of one of them would result in a dead card. I've circled them on both the processor card and the tuner card.

Pin 1 is on the bottom left with the tab at the top; I've marked several to indicate that. On the processor card I've also circled a mounting hole in black. Use that for the ground lead of your DMM.

The output voltage of most of these will be included in the part number, so the best way to report the readings would be as the voltage on each pin ("3.32 volts", not "about three volts", please, and the part number of the IC.

PlainBill
Attached Images
File Type: jpg Insignia NS-32LCD Tuner top-1.JPG (190.6 KB, 280 views)
File Type: jpg Insignia NS-32LCD Processor top-1.JPG (199.5 KB, 246 views)
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Old 08-07-2010, 05:52 PM   #15
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Default Re: Insignia 32" LCD TV Model# NS-32LCD

OK well, both cards seem dead, I think... But I traced 4 24v leads that go from the board to the backlight panel, then go to the processor board. The return signals are 3.59v and .21 mV. Doesn't sound good. Attached a picture. Other things you circled have notes next to them. Figured faster to see picture and read readings, than my type it all out and you try to decypher what I'm trying to say.. LOL
Attached Images
File Type: jpg board 2 top labeled.jpg (780.9 KB, 162 views)
File Type: jpg board top labeled.jpg (844.9 KB, 143 views)
File Type: jpg LCD panel.jpg (649.2 KB, 126 views)
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Old 08-07-2010, 08:37 PM   #16
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Default Re: Insignia 32" LCD TV Model# NS-32LCD

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Originally Posted by ajsemtb View Post
OK well, both cards seem dead, I think... But I traced 4 24v leads that go from the board to the backlight panel, then go to the processor board. The return signals are 3.59v and .21 mV. Doesn't sound good. Attached a picture. Other things you circled have notes next to them. Figured faster to see picture and read readings, than my type it all out and you try to decypher what I'm trying to say.. LOL
First of all, let me verify something. Did you make all these voltage measurements with all cables hooked up, the TV plugged in, and the standby light off? If so, we have a 'smoking gun'.

The voltages on the cable to the inverter are acceptable. This is the way the signals flow on this LCD TV.

You have a power supply with two sections - a 5V Standby section that is on whenever the TV is plugged in, and a 24 volt Main supply. The 5V and 24V goes the the main board. It will also go to any other board that requires it - the inverter, and the audio amplifier. It may go directly, be routed through the main board, or through a distribution board. This design apparently routes the 24V inverter power through the main board. The main board adds two signals to the cable that goes to the inverter. These are On/Off and Brightness.

On the main board the 5V standby supply powers a standby processor. At a minimum this processor interprets signals from the IR receiver and from the control panel on the TV. And it sends the signal to the power supply which directs it to turn on the Main supply.

The 24V Main supply goes through a series of voltage regulators which drop it down to the voltages required by the signal processing components - chiefly 3.3, 2.5, and 1.25 volts.


Hmm, something strange. You mention 12V in some areas and 24V in others??

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Old 08-07-2010, 08:43 PM   #17
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Default Re: Insignia 32" LCD TV Model# NS-32LCD

Yes, I hooked everything back up, and plugged in the set, and pushed the power button which took it off stand by. I verified 110 (it was 119V) going in, and at both sides of the primary fuse, then checked the pins in DC mode leaving the board. Some pins designate they are supposed to be 24V others are marked for 12V and some marked for 5V. Did you say you found a service manual? Do you have the link for that? I don't know how to read a schematic fluently, but sometimes I can find what I'm looking for as far as voltages at points and so forth.
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Old 08-07-2010, 08:58 PM   #18
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Default Re: Insignia 32" LCD TV Model# NS-32LCD

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Originally Posted by ajsemtb View Post
Yes, I hooked everything back up, and plugged in the set, and pushed the power button which took it off stand by. I verified 110 (it was 119V) going in, and at both sides of the primary fuse, then checked the pins in DC mode leaving the board. Some pins designate they are supposed to be 24V others are marked for 12V and some marked for 5V. Did you say you found a service manual? Do you have the link for that? I don't know how to read a schematic fluently, but sometimes I can find what I'm looking for as far as voltages at points and so forth.
Here's the link. Upon examining the 'hit', it appears Google got creative with it's match.

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Old 08-08-2010, 02:00 AM   #19
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Default Re: Insignia 32" LCD TV Model# NS-32LCD

Are the fuses on yours surface mount?Do you have a diode setting on your meter?The one that beeps when you touch the probes together.Did you also try that setting?That is how I found the problem on mine.The meter only beeped once,and not a continuous beep like it should.On the ohm setting,I still got a reading,but that was only because the connection was still there,just through other nearby components,which made me think the fuse was still good until I tried the diode setting.I hope this helps.Thank You very much!
Tyler
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Old 08-09-2010, 03:41 PM   #20
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Default Re: Insignia 32" LCD TV Model# NS-32LCD

OMG! 70Judge is right! I tested with the ohms meter, and it had a reading (by backing around I'm sure) but the continuity test and the diode test both failed! The FU502 fuse is dead, the FU503 works. I will order this tiny little fuse and hopefully have a TV again! I'll reply when the part comes in.
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