BigCatAndy wrote: ↑Mon Aug 30, 2021 1:57 am
axur-delmeria wrote: ↑Mon Aug 30, 2021 12:10 am
The fact that you don't know whether the screen is LED- or CCFL-backlit tells me that your preparations weren't enough.
That said, LCD swaps between non-identical laptops is a nerve-wracking affair even for me, especially when it's a client's laptop as it's my reputation on the line and have to pay for a replacement if I end up wrecking it. Fortunately, I haven't wrecked anyone's laptop while changing the LCD panel.
In your case though... could you shine a bright flashlight and see if you can gleam an image on the screen while the laptop is on? Hopefully it's just a backlight issue.
@axur-delmeria, I do not need a lecture (especially considering that you do not really know the situation). You mentioned 3 times yourself without addressing a problem - I do not think, this will help me (even if I cannot say if my display was CCFL or LED).
additional information: I haven't just swapped the panels, I took the whole screen. The only thing I did - plugged R400-connector into T400, and then back T400-connector. Both units were complete with their original displays.
Hello,
I don't think Axur lectured you. I've read a lot of his posts and the informations he gives are always very valuable.
The fact is that it's always complicated to change a screen. Screen alone, or the upper assembly of the laptop. If I had to change the whole assembly, I would only use a replacement from a identical machine. And if I want to change only the screen, then I look at the HMM to list the exact references of the compatible screens. It's really complicated, because once you know what you need, you must again be veeeeeery careful about what you buy (and particularly on the aftermarket). The sellers don't always sell what they advertise (or they do, but we don't read the little characters on the advertisement). Brands, models, FRUs, revisions and even specs can often change and what you receive will be different just because of what the seller has in stock when he prepares your parcel. To find THE good screen can be very time-consuming and very tricky sometimes (even more when you're on a budget) !
By the way, the difference between CCFL and LED is about the backlight system of the screen. CCFL (Cold Cathode Fluorescent Lamp) is an old technology, it uses neons to emit light and you also have a piece of hardware named an inverter to give them the energy. The LED technology is more recent and it uses, well, some LEDs to enlighten the screen. LEDs need less energy, are less fragile, more durable, offers a better display – colors representation, brightness –, you don't need an inverter anymore and you can also have thinner screens. Only advantages !
And I suppose you've guessed it : the two technologies are not compatible. Don't quote me on this, but I think you can have connectors physically identical, but with a different pinout. Then it's understandable that you can't have something running properly. It's like the sockets in modern desktop PCs. If you have a look at the socket 1151, for Intel, it was the same for the 6ᵗʰ, the 7ᵗʰ the 8ᵗʰ and the 9ᵗʰ generation of the Core processors. But the pinout is different for the 6ᵗʰ and 7ᵗʰ on one hand, and 8ᵗʰ and 9ᵗʰ on the other hand. So, if you can install for example a 9ᵗʰ generation Core CPU on a 7ᵗʰ generation motherboard, it fits but nothing more.
You really should try to shine a bright flashlight like Axur said, to see if something can be visible. If it's visible, then it means it's a backlightning problem. The T400 uses LED backlit screens when the R400 uses CCFL ones (that's what I found after a quick research, do not hesitate to search even more if you want
). For me, it's not possible to do inversions between the two displays.
W.
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