Lenovo li2341twf Monitor - No Power

[mikey32230]

Re: Lenovo li2341twf Monitor - No Power

The failure mode of the MLCC (Multi Layer ceramic Capacitor) type capacitor is shorted circuit, so try removing that cap and see if the low resistance will go away

Okay, so just so I understand correctly.

I am desoldering C702 and then... testing its resistance out of circuit?
or am I powering the switchboard without the resistor in circuit?

[budm]

Re: Lenovo li2341twf Monitor - No Power

Okay, so just so I understand correctly.

I am desoldering C702 and then... testing its resistance out of circuit?
or am I powering the switchboard without the resistor in circuit?

You will remove C702, and then you will take the resistance reading bewteen the two solder pads on the board where C702 used to be connected to to see if the low resistance is still exist on the board.
If the shorts is n longer there without the cap, then you can power up the board for testing for now.
C702 is a capacitor not a resistor.

[mikey32230]

Re: Lenovo li2341twf Monitor - No Power

You will remove C702, and then you will take the resistance reading bewteen the two solder pads on the board where C702 used to be connected to to see if the low resistance is still exist on the board.
If the shorts is n longer there without the cap, then you can power up the board for testing for now.
C702 is a capacitor not a resistor.

Sorry, I wasn't thinking when I said that C702 was a resistor.

Okay. I desoldered C702 and I still get 2.6-2.8 resistance between those solder pads.

[budm]

Re: Lenovo li2341twf Monitor - No Power

Since that cap is more likely to be the Filter cap for VCC of that IC, unless the there is anything else that are connected in parallel with that C702, then the only left will be that IC is shorted.

[mikey32230]

Re: Lenovo li2341twf Monitor - No Power

Since that cap is more likely to be the Filter cap for VCC of that IC, unless the there is anything else that are connected in parallel with that C702, then the only left will be that IC is shorted.

So what are my options at this point? Am I stuck because there is no way for me to get a replacement IC? I would love to keep pursuing this repair in anyway possible.

[budm]

Re: Lenovo li2341twf Monitor - No Power

Well, we need the spec of the IC to see which pin is the VCC pin, or you can remove the IC and replace it.
http://nl.aliexpress.com/store/produ...toreId=1771244
or try EBAY.

[mikey32230]

Re: Lenovo li2341twf Monitor - No Power

Well, we need the spec of the IC to see which pin is the VCC pin, or you can remove the IC and replace it.
http://nl.aliexpress.com/store/produ...toreId=1771244
or try EBAY.

So I have searched pretty thoroughly and I cannot find anything close to that IC part number. The link you listed is the closest I have seen.

Is there anyway to "guess and check" for the VCC pin? Can I just replace it with the IC with the one in the link you provided? or will that not work because it is not the same part number?

[mikey32230]

Re: Lenovo li2341twf Monitor - No Power

Maybe only some mosfet or voltage regulator has blown.


Is the fuse still good?

That monitor uses an external power supply, did you test it with your working monitor?

Do you have any advice at this point while budm is in surgery?

[mike in bremerton]

Re: Lenovo li2341twf Monitor - No Power

I know it has been a little while but did you ever get the answer to fix the problem?

[mikey32230]

Re: Lenovo li2341twf Monitor - No Power

I know it has been a little while but did you ever get the answer to fix the problem?

A little while (6 years) later…

Unfortunately not. I probably still have the disassembled monitor laying around somewhere. I think I ended up desoldering something poorly, probably rendering whatever component useless, became too busy, forgot where I left off and gave up.

Sorry :/