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Repair guides, disassembly information, and troubleshooting information for the 5th generation AMD ThinkPad E14, Lenovo's 14-inch affordable business laptop, released early 2023.

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LCD Backlight not working. Potential blown fuse.

I checked for continuity. The issue is here (F1 fuse) but I'm not sure if it's missing.

My question is if someone can circle where the backlight fuse F1 is located in this photo?

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Thanks.

Update (01/13/26)

I couldn't find Fuse# 3A_32V_0497003PKRHF.

I found a replacement that I believe is very similar.

Will this replacement Fuse work?

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Thank you again for your help. I really appreciate it.

Update (01/14/26)

After further inspection of the schematic posted,

It looks like c310 and c313 are missing on the NM-F351 motherboard.

Could c310 and c313 missing cause the dim backlight on the LCD?

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Hi @rickfix2026

If the motherboard is model number NM-F351 (printed on the board), below is a composite image (whole board - top and zoomed in section of board - bottom) from the NM-F351 boardview file showing the location of the F1 backlight fuse (fuse type # 3A_32V_0497003PKRHF).

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(click on images)

Update (01/14/26)

Hi @rickfix2026

Run the LCD self test and check if it works OK just in case it is not a backlight power supply problem but something else e.g. problem with the backlight enable circuit on the motherboard (connects to pin 49 EDP connector)

If the test proves no good, here's an image of the schematic showing the backlight power supply through the fuse to pins1-3 on the EDP connector on the motherboard.

With the laptop turned on etc, check what voltage is on those pins.

The feed states V9B+ so maybe it should measure 9V DC but as to why so many capacitors are sitting on the supply line I don't know. Maybe need to smooth out the supply.

If one of the other capacitors on the line i.e. C19, C10, C307, C314 & C315 was faulty and shunting the voltage to earth this may be the reason for it being faint

There may be a lot of current flowing (Amps) so try not to short the pins to anything else when testing for the voltage.

If the correct voltage is there you may have to disassemble the display unit and check what the voltage is on pins 1-3 at the other end of the EDP cable where it plugs into the LCD panel, in case the cable has been damaged where it passes through the hinge to get from the motherboard to the lid.

If the voltage at the LCD panel is OK then most probably it's a faulty panel which would have to be replaced.

Here's the hardware maintenance manual.

Go to the bottom of p.82 (89 of 108 pdf) in the manual to see how to remove the LCD unit

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(click on image)

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Yes. The motherboard is NM-F351.

Thank you for confirming.

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@rickfix2026

The fuse you linked may be a bit small in that it may not bridge the distance between the two soldering point on the motherboard.

Here's a link that shows the common smd package sizes that may help.

You have linked a fuse (which has the correct rating 3A/32V) with a package size of 0402 (see link).

The 0497 size shown for the part is a non standard size so it may be easier to get one a fuse that's slightly longer so as to bridge the gap but not too wide as not to touch any other components on the sides (or the ends either)

Possibly a 3A 32V 0603 fuse perhaps

door

@jayeff looks to me like the white (far right vertical component) is F1 and the middle component that looks smushed ;-) (missing) would be C310 which is a 0.1µF 25V capacitor in a 0402 and is part of the LEDVDD circuitry right next to F1 :-)

door

@oldturkey03

probably right - old eyes ;-(

It's a bit different to the boardview but the OP confirmed the board model number

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@jayeff I know, me too ;(

Had to zoom in quite a bit ;)

the board view is vertically flipped. The board number is right.

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