LG 37LC2D Major S/C Testing F9223L

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hi

Was going to post in the other 37LC2D post but that one semed more related to the very common LG cap failure

Anyway, got this tv and found the Bridge S/C cant see anything else on board and wondered if anyone can give me a pointer on how to test the 13 legged I/C , I have already removed it from the board


Thanks in advance

[tom66]

Re: LG 37LC2D Major S/C Testing F9223L

What's the part # of the device?

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Re: LG 37LC2D Major S/C Testing F9223L

What's the part # of the device?

Sorry Tom, I only put the part number in the title F9223L (Datasheet attached)

[tom66]

Re: LG 37LC2D Major S/C Testing F9223L

Test for shorts (both ways):
23 to 20
23 to 19
19 to 4
7 to 8

Any short circuit indicates a fault.

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Re: LG 37LC2D Major S/C Testing F9223L

Cheers Tom...23-20 23-19 s/c'd

Going to order one now

[tom66]

Re: LG 37LC2D Major S/C Testing F9223L

If that internal FET failed short inside the device, you may also need to test external devices. I don't know how it is connected because the second fet seems to be floating -- for external use. Not sure why.

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Re: LG 37LC2D Major S/C Testing F9223L

The only other thing I can see was the bridge, If I remember rightly they normally take a couple of the small smd caps and resistors on the underside, but these seem to be ok, I found another old board with the part in thats fine so going to pop it in later

Will let you know how it goes

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Re: LG 37LC2D Major S/C Testing F9223L

Hi

Fixed with a different fault

replaced the Bridge/F9223L and recapped the secondary side, the problem I am having is with the sound and digital tv. The speakers keep crackling and when you try and tune in Digital channels it refuses to start, I could get round this by doing a factory reset so it searches for analogue then digital but its not jumping to channel 21 or even trying to search for digital.

I have another TV that is fully working, as soon as I put the psu int the working tv I get the same problems...so I know it has to be something on the psu

Any help appeciiated

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Re: LG 37LC2D Major S/C Testing F9223L

Sorry should of added my 3.4 line is down at 1.83v

[tom66]

Re: LG 37LC2D Major S/C Testing F9223L

If your 3.4V is low, you will get those problems.
The controller IC on 3.4V is failed or the capacitors around it are bad.

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Re: LG 37LC2D Major S/C Testing F9223L

Cheers Tom

I have changed the two fets and regulator on the underide of the board but still the same.

Any other pointers

[tom66]

Re: LG 37LC2D Major S/C Testing F9223L

Did you change the ones for the 6V or 3.4V?

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Re: LG 37LC2D Major S/C Testing F9223L

3.4 as shown in budm diagram on the other post..I will just go an check the 6v line now

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Re: LG 37LC2D Major S/C Testing F9223L

I am getting 6.1v

[tom66]

Re: LG 37LC2D Major S/C Testing F9223L

Check what 3.4V rises to when you disconnect the main board connector -without- the POWER ON signals (PSON, BLON etc.)

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Re: LG 37LC2D Major S/C Testing F9223L

I have just been looking throough the other thread regarding this tv and there is a little contradiction Budm shows a picture of 3.4 buck and fets but then later in the post you say this is the 6v line and the 3.4 volts is to the left of the board...bit confussed now

Is the 3.4 v line by the inverter plugs or is that the 6v line...I think I have replaced all the 6v fets and ic

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Re: LG 37LC2D Major S/C Testing F9223L

Budm Put

https://www.badcaps.net/forum/showth...t=18218&page=5 post number 81

You put
https://www.badcaps.net/forum/showth...t=18218&page=6 Post 103

[tom66]

Re: LG 37LC2D Major S/C Testing F9223L

You can trace it through the inductor and capacitors and find the 3.4V one. I no longer have this TV or board in my possession.

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Re: LG 37LC2D Major S/C Testing F9223L

I have uploaded the two pics, on your pic you say the 3.4 is to the left but budm says his pic is the 3.4v ic and fets which is the one on the right of your pic...confused...I am too.

[tom66]

Re: LG 37LC2D Major S/C Testing F9223L

In the middle/right of the first pic.
Budm's left is different to your left?