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Old 02-28-2021, 01:35 PM   #1
knoxrebel
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Default Insignia ns-55d420a16. Blinking red light no backlight

Tested power supply output getting 12 volts with no main board. Tested with main board 12 volt output is dipping appears that power supplies restarting. Hooked external load directly to 12 volt and it's doing the same thing. Suggestions?
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Old 02-28-2021, 01:45 PM   #2
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Default Re: Insignia ns-55d420a16. Blinking red light no backlight

Try heating the electrolytic capacitors on the powerboard with a hairdryer, see if the voltages stabilize if only for a bit.

Last edited by nomoresonys; 02-28-2021 at 01:53 PM..
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Old 02-28-2021, 01:52 PM   #3
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Default Re: Insignia ns-55d420a16. Blinking red light no backlight

What load did you put on the 12V supply line. It says maximum 3 Amp. Does the 14V supply line also drop in line with the 12V ?
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Old 02-28-2021, 02:15 PM   #4
knoxrebel
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Default Re: Insignia ns-55d420a16. Blinking red light no backlight

Unfortunately no change. 12v drops to 3v then cycles between 0 and 3v. Remove all but main filter caps and tested esr, they are all low, but i believe .02 is within spec for a 25v 1000Uf low esr cap.
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Old 02-28-2021, 02:41 PM   #5
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Default Re: Insignia ns-55d420a16. Blinking red light no backlight

Quote:
Originally Posted by dick_barton View Post
What load did you put on the 12V supply line. It says maximum 3 Amp. Does the 14V supply line also drop in line with the 12V ?
Not sure on the load, but it was dialed all the way down.

The board silkscreen showed 16v not 14, and its didn't match up with the connector so i assumed it was incorrect. I'm not getting any other voltage other than the 12 with or without the mainboard plugged in.
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Old 02-28-2021, 03:53 PM   #6
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Default Re: Insignia ns-55d420a16. Blinking red light no backlight

Look the solder joints over on the powerboard real closely, see if you have any bad/cold joints. As always be VERY CAREFUL when dealing with the DEADLY/HOT side of the board.

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Old 02-28-2021, 03:57 PM   #7
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Default Re: Insignia ns-55d420a16. Blinking red light no backlight

Also check over the diodes and resistors if you haven't already.
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Old 02-28-2021, 04:06 PM   #8
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Default Re: Insignia ns-55d420a16. Blinking red light no backlight

If your power supply matches the schematic then if the 12V is running so should the 14V (16V) because they are both derived from the same transformer T831
If that supply is missing then you need to double check all the components in that area.
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Old 02-28-2021, 05:17 PM   #9
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Default Re: Insignia ns-55d420a16. Blinking red light no backlight

maybe also check VD829, VD825 and VD805.
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Old 02-28-2021, 06:58 PM   #10
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Default Re: Insignia ns-55d420a16. Blinking red light no backlight

Thanks for the assistance. Ended up being VD819 (MBR101 50 CTF - E1 434881). Having trouble finding a suitable replacement.
Would FCH10A20 suffice?

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Old 02-28-2021, 07:31 PM   #11
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Default Re: Insignia ns-55d420a16. Blinking red light no backlight

Data sheet FCH10A20: https://www.alldatasheet.com/datashe.../FCH10A20.html

Data sheet MBR10150CTF-E1: https://www.alldatasheet.com/datashe...150CTF-E1.html do those match up?
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