New screen, no backlight.

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CyberPowerPC Laptop

Repair guides for laptops produced by CyberPowerPC.

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BasicJack @jack9722

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게시됨: 2023년 8월 25일

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New screen, no backlight.

Hello,

My screen went bad on my Tracer VI Edge Pro I15X, and I replaced it with a new one. I can see that I am getting picture on the screen when holding a flashlight behind it, but zero backlight. I have also tried a different display ribbon cable.

I am beginning to think it could be a fuse, but wanted some guidance if someone would be able to offer it.

Thanks in advance.

EDIT: I added photos of the front and back of the motherboard, as well as a close up of the video connector for reference.

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jayeff @jayeff

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Hi @jack9722,

Did you disconnect the battery from the motherboard, before replacing the screen?

Are you sure that you got the correct model screen as a replacement, e.g. is it the same make and model number screen?

If they're different, find the make and model information on the back of both of the LCD panels and search online for (insert make and model) datasheet for each screen to hopefully find them. The datasheet will have the pinout wiring connections so that you can make sure that the new screen is the same as the original and that it is compatible with the motherboard's video connector wiring.

If they are the same or if you can't find the datasheets, what the make and model number of the motherboard(printed on motherboard) as the schematics will be required to find out if there is a fuse or not in the backlight power supply? Some motherboards don't have a backlight power fuse. They turn a power mosfet on and off to supply the backlight power.

Post some clear close up images of the motherboard in your question, especially showing the area a couple of inches either side of the video cable connector. If there is a fuse maybe it can be found. Here's how to 기존 질문에 이미지 추가하기

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Thanks so much for the reply!

Yes, I did disconnect the battery before removing the old screen and installing the new screen.

The screen is the same model as the one that was originally used.

I will gather the photos of the motherboard, as well as the model of it when I get home this afternoon and post them for you to have a look at.

BasicJack 의 2023년 8월 25일

@jayeff I added images to this post for reference.

BasicJack 의 2023년 8월 25일

@jack9722

Assuming the 4th image posted, counting down from the top, is showing the video cable connector, there are two smd fuses marked with the letter "k" directly below the middle of the connector.

Use an Ohmmeter and check if they both measure 0.00 Ohms i.e. a short circuit.

If they do then they are OK as this is the normal test for a good fuse. If not then they're faulty.

K = a current rating of 1.5A. I don't know the voltage rating of the fuse but a lot of smd backlight fuses in laptops have a 35V voltage rating but it is the current rating that is important.

If they're both OK what is the screen manufacturer's make and model number of the LCD display (not the PC maker's part number for the screen) which is usually on a sticker on the back?

I can't find the schematics for the motherboard (the laptop is too new) so hopefully the datasheet for the LCD display can be found as it will have the cable pin out info so at least the wires for the backlight and also the backlight enable/disable lead will be known

jayeff 의 2023년 8월 25일

@jayeff

I measured and it seems that one of the K fuses does not have continuity. In that same picture you referenced, it would be the one on the right.

Should I replace this fuse? Or should I attempt to jump it first just to see if it that’s my issue?

I really appreciate your help. Your a lifesaver!

BasicJack 의 2023년 8월 26일

@jack9722

Personally I would replace it.

Fuses are there to protect the equipment from further damage, in the event of a problem with the part of the circuit that they're there to protect..

For example, if you just jump it there may be other problems as yet unknown which may cause excess current to flow through the jumper wire when obviously there shouldn't be and this could damage the new screen.

If you replace the fuse and it holds and everything works OK then all is well.

If you jump the fuse and it works, perhaps it may be OK but then for how long would it work without the safeguard of a fuse. To me this is too risky

If you jump the fuse and it doesn't work you may not know what other damage has occurred, if any, until you replace the fuse and try again.

But then again it is not my laptop ;-)

Perhaps order 2-3 fuses just in case

jayeff 의 2023년 8월 26일

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Thanks so much for the reply!

Yes, I did disconnect the battery before removing the old screen and installing the new screen.

The screen is the same model as the one that was originally used.

I will gather the photos of the motherboard, as well as the model of it when I get home this afternoon and post them for you to have a look at. — BasicJack
@jack9722

Assuming the 4th image posted, counting down from the top, is showing the video cable connector, there are two smd fuses marked with the letter "k" directly below the middle of the connector.

Use an Ohmmeter and check if they both measure 0.00 Ohms i.e. a short circuit.

If they do then they are OK as this is the normal test for a good fuse. If not then they're faulty.

K = a current rating of 1.5A. I don't know the voltage rating of the fuse but a lot of smd backlight fuses in laptops have a 35V voltage rating but it is the current rating that is important.

If they're both OK what is the screen manufacturer's make and model number of the LCD display (not the PC maker's part number for the screen) which is usually on a sticker on the back?

I can't find the schematics for the motherboard (the laptop is too new) so hopefully the datasheet for the LCD display can be found as it will have the cable pin out info so at least the wires for the backlight and also the backlight enable/disable lead will be known — jayeff
@jayeff

I measured and it seems that one of the K fuses does not have continuity. In that same picture you referenced, it would be the one on the right.

Should I replace this fuse? Or should I attempt to jump it first just to see if it that’s my issue?

I really appreciate your help. Your a lifesaver! — BasicJack
@jack9722

Personally I would replace it.

Fuses are there to protect the equipment from further damage, in the event of a problem with the part of the circuit that they're there to protect..

For example, if you just jump it there may be other problems as yet unknown which may cause excess current to flow through the jumper wire when obviously there shouldn't be and this could damage the new screen.

If you replace the fuse and it holds and everything works OK then all is well.

If you jump the fuse and it works, perhaps it may be OK but then for how long would it work without the safeguard of a fuse. To me this is too risky

If you jump the fuse and it doesn't work you may not know what other damage has occurred, if any, until you replace the fuse and try again.

But then again it is not my laptop ;-)

Perhaps order 2-3 fuses just in case — jayeff

BasicJack @jack9722 평판: 65 4 · Answer 1 · 2023-08-28T07:57:44-07:00

BasicJack @jack9722

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게시됨: 2023년 8월 28일

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@jayeff

Adding a solution here. I ended up jumping the fuse with a pair of tweezers while the computer was turned off, holding the tweezers in place, and powering on the machine. Sure enough, the screen powered right on, full backlight in all of it's glory.

I ordered 3 "K" labeled 1.5A fuses on eBay, should be here later this week. I appreciate the assistance in diagnosing the issue and helping me find a fix!

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CyberPowerPC Laptop

New screen, no backlight.

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