Re: LG 47" 47LV4400 Shutting Off LV Series
I reflowed most all of the through hole components on the power supply board. TV worked for about 25 minutes and shut off again. I'll look at replacing the electrolytics now.
Acesales
Senior Member
Last Activity: 11-18-2023, 07:59 AM
Joined: 06-07-2017
Location: Owatonna, MN
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Re: LG 47" 47LV4400 Shutting Off LV Series
I heated the electrolytics on the power board and it came back to life! It ran for five minutes then the wife said we have to leave so I turned it off. I tried heating them again and it won't stay working this time. Was heating them to lower the ESR a one time only test or was it all coincidence?Leave a comment:
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Re: LG 47" 47LV4400 Shutting Off LV Series
Do you mean electrolytics on the main board or the power supply board? ThanksLeave a comment:
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Re: LG 47" 47LV4400 Shutting Off LV Series
Ok, I was able to go in and turn brightness and backlight all the way to zero. It still shut off right away, seems like it's getting worse.Leave a comment:
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LG 47" 47LV4400 Shutting Off LV Series
Hello again, my year 2011 47" LG 47LV4400-UA is now shutting off after a few minutes. Turns on and works fine then loses backlight, sound, and picture. Power light does not change, stays blue. I don't see a BGA processor to reflow like other LV series. Do the edge type processors also have cold solder joint problems or is this a different issue? Thanks... -
Re: 2015 Insignia NS-55D421NA16 No Standby-PSU Sparks
Does anyone know where I can get the correct schematic for this TV?Leave a comment:
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Re: 2015 Insignia NS-55D421NA16 No Standby-PSU Sparks
I drew this schematic based on what I can see on the board as well as continuity testing. I can't figure out what voltage regulator to use. The pinout doesn't make sense to me. Any ideas?
PS- budm, I don't have a good power supply to simulate the standby voltage, unfortunately. All I have is an old Lab-Volt non regulated that I use for tube radio repair....Leave a comment:
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Re: 2015 Insignia NS-55D421NA16 No Standby-PSU Sparks
A SOT-23-5 5 pin converter makes more sense based on the board pinout. Not sure which one is correct, though. Strike 2 or 3 for my schematic....Leave a comment:
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Re: 2015 Insignia NS-55D421NA16 No Standby-PSU Sparks
Here is a pic with ID's....Leave a comment:
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Re: 2015 Insignia NS-55D421NA16 No Standby-PSU Sparks
Pad 2 goes to the left pin of the PWR UPGRADE connector (GND). Pad 2 to the 12V pin, or right hand pin in photo shows a climbing resistance like a capacitor charging.Leave a comment:
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Re: 2015 Insignia NS-55D421NA16 No Standby-PSU Sparks
Pad 1 goes to a >1 ohm resistor below and to the left.
Pad 2 goes to the left side of the resistor under and to the right of pad 3. It measures 5.45K.
Pad 3 goes to a common point between the two resistors under and to the Right of pad 3. Both resistors measure approx. 5.45K.
Pin 4 has a bad trace.
Pin 5 goes back to the 12V supply.
Pin 6, the upper left pad opposite the arrow goes to the 4R7 inductor above it.Last edited by Acesales; 02-23-2018, 07:21 PM.Leave a comment:
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Re: 2015 Insignia NS-55D421NA16 No Standby-PSU Sparks
Here are the close ups....Leave a comment:
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Re: 2015 Insignia NS-55D421NA16 No Standby-PSU Sparks
Here is the service manual I found. I couldn't read the part number on the burnt IC. I'm wondering if my PSU requires a different part number than what is listed in the schematic.
JR, there is no continuity to the "power upgrade" connector. I can chase pin 1 through a >1 ohm resistor and a capacitor.
budm, yes, shorted between pin 2 and ground, unless pin 2 is ground and I am chasing the wrong converter part number....Leave a comment:
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Re: 2015 Insignia NS-55D421NA16 No Standby-PSU Sparks
More random unidentified circuits. The schematic I found for this TV is not great but the manual is for a Hisense, not Insignia, but very close....Leave a comment:
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Re: 2015 Insignia NS-55D421NA16 No Standby-PSU Sparks
Pin 1 (GND) is supposed to be ground but I have an inifinite reading to several ground points.....chassis screws?
Pin 2 (SW) is shorted to ground. You guys were right.
Pin 3 (IN) 5.45K to ground and 0 volts.
Pin 4 (FB) trace is damaged.
Pin 5 (EN) shows 12VDC.
Pin 6 (BST) reads 59.5 ohms to ground.Leave a comment:
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Re: 2015 Insignia NS-55D421NA16 No Standby-PSU Sparks
Budm, I misidentified the circuit in question. The problem circuit is actually the 5V STB supply circuit. My schematic is wrong in regards to part ID's. So the MP1470GJ-Z actually burnt. I saw 5 pins, I wonder if the initial spark was a pin burning off....Leave a comment:
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Re: 2015 Insignia NS-55D421NA16 No Standby-PSU Sparks
The maximum allowable voltage in for the M3406 step down converter is 6.5V. I am measuring 12V after removing the burnt chip. Is it high because there is no load?Leave a comment:
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Re: 2015 Insignia NS-55D421NA16 No Standby-PSU Sparks
Test to ground;
RUN= infinite
FB= 59 ohms
SW= 5.4KLeave a comment:
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Re: 2015 Insignia NS-55D421NA16 No Standby-PSU Sparks
I believe this is the circuit for the burned step down converter....Leave a comment:
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Re: 2015 Insignia NS-55D421NA16 No Standby-PSU Sparks
Now this step down converter M3406-ADJ self destructed on it's own. Any ideas?...Leave a comment:
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