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Old 09-30-2020, 02:41 PM   #1
BradW
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Red face Insignia LED TV - Won't turn on

I am trying to repair a single-board LED Insignia TV.
Model NS-39D220NA16

When plugged-in, the red standby LED lights for about 1-second and then goes out. It will not come back on until unit is unplugged and then plugged back in.
Rinse and repeat.

I have no schematics and the board is not marked very well.
On the underside of the board, I did find a test point for 1.15v Standby and that reads 1.17v.
There is also a 5v Standby and that does read 5v.

I have tested all diodes and they appear Ok as do the transistors that I could identify and check. (Tested using ohm readings and Diode mode)

All caps look very good but I have not unsoldered and checked although I plan on doing that.

Any suggestions on what to check next?
Insignia NS-39D220NA16 TV board.jpg
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Old 09-30-2020, 04:11 PM   #2
neilc6
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Default Re: Insignia LED TV - Won't turn on

You need to determine if the TV is turning on and off with no backlight or not turning on at all. If the TV turns on with no backlight, you probably have bad backlights. If the TV doesn't turn on at all, you possibly have a bad eeprom.
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Old 10-01-2020, 09:02 AM   #3
BradW
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Default Re: Insignia LED TV - Won't turn on

Stndby LED turns off by itself in a second or less.
Nothing happens when I press power button. I've used bright flashlight to check for image but there is nothing so I don't believe I have a picture.

Is it possible to get a new eeprom or should I cut my losses and just get a replacement board?

I think I've identified the eeprom as shown in attached pic.
The chip is labeled 25Q32BSIG and appears to be a reprogrammable chip.
Attached Images
File Type: jpg 25Q32BSIG eeprom for Insignia TV.jpg (893.7 KB, 6 views)
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Old 10-01-2020, 09:16 AM   #4
neilc6
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Default Re: Insignia LED TV - Won't turn on

With the TV unplugged, spray the eeprom with an upside down can of duster to cool it. Plug in the TV and see if it turns on.
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Old 10-01-2020, 11:01 AM   #5
BradW
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Default Re: Insignia LED TV - Won't turn on

Spraying (freezing) the eprom didn't work but I did notice that the Stndby LED went ON, OFF and then back ON for a few seconds. It went off again and TV would not turn on.

Since something different happened, I decided to put board in the freezer for a few minutes.
This time, the SB LED stayed on and the TV powered up Ok and I was able to navigate the menus, etc.

I let it run for 10-min. and then powered off.
SB LED went out and nothing would work after that.
Froze board again (a little longer this time) but no luck.

So the TV functionally works but it just refuses to power on consistently.
The end user did say that they could get the TV working sometimes if they plugged in and out many times so I think I just got lucky on that one time.

I also let it on for a few minutes and felt many components and nothing seemed warm or hot to touch.

Any other thoughts before I just replace the board?
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Old 10-02-2020, 06:00 AM   #6
Davi.p
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Default Re: Insignia LED TV - Won't turn on

Do oyu have an eprom programmer and better also a chip clip? If yes put it in the freezer then read the flash in a hurry then rewrite it on, retry, if this doesn't work try the reflow on the cpu, or pressing on it with a shim under the board in the menatime you turn on the set.
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Old 10-02-2020, 09:28 AM   #7
neilc6
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Default Re: Insignia LED TV - Won't turn on

You can reprogram the eeprom with a cheap ch341 usb programmer.

The processor doesnt have a heatsink and is not bga so no point in reflowing it.
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Old 10-03-2020, 02:03 PM   #8
BradW
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Default Re: Insignia LED TV - Won't turn on

Thanks for tips.
I have ordered a replacement eeprom for my TV model from ShopJimmy.com.
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Old 10-19-2020, 11:57 AM   #9
BradW
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Default Re: Insignia LED TV - Won't turn on

The replacement eeprom fixed the TV!
Thanks very much for suggesting that.
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Old 10-19-2020, 03:16 PM   #10
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Default Re: Insignia LED TV - Won't turn on

Nice work, another one saved.
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