SXGA+ in a T60 not working properly

[benevans]

Hi there,

I put an SXGA+ (specifically described as LTN141P4-L02 Laptop Notebook Screen SXGA+ 1400x1050 14.1″ 30 Pins from where I got it) in my T60, and it’s not displaying correctly. It’s zoomed into the top left corner of the screen and it looks like every second pixel is white or something... Here is a picture:

So I’m wondering if anyone has any ideas. The possibilities I’ve thought of are:

• I need a new inverter card
• It’s some kind of driver issue (but I tried booting with a fresh linux installation media and looks the same, also looks like this in the bios)
• I ordered the wrong screen
• They sent me a faulty screen (If so, let this post be a warning not to buy screens from lpsscreens.com, which is where I got it)
• something I’ve not considered

I really appreciate any thoughts or advice on this. Not sure what my next step is towards fixing it.

[axur-delmeria]

Check if the LCD's EDID can be read-- run "sudo get-edid | parse-edid" (you need the "read-edid" package installed). If the LCD panel's EDID cannot be read, the BIOS defaults to XGA (1024x768) IIRC.

[Robsa990]

It could be an incorrect EDID or the LVDS cable is not connected properly. I've had the "white pixel" issue with a loose LVDS connection to the screen when I re-assembled the laptop.

[benevans]

Thanks for the responses. I ran "sudo get-edid | parse-edid" and this is what came out:

Attempting to use i2c interface
Looks like no busses have an EDID. Sorry!
Attempting to use the classical VBE interface

Performing real mode VBE call
Interreupt 0x10 ax=0x4f00 bx=0x0 cx=0x0
Function supported
Call successful

VBE version 300
VBE string at 0xc0254 "ATI ATOMBIOS"

VBE/DCE service about to be called
Report DDC capabilities

Performing real mode VBE call
Interrupt 0x10 ax=0x4f15 bx=0x0 cx=0x0
Function supported
Call Failed

Reading next EDID block

VBE/DDE service about to be called
Read EDID

Performing real mode VBE call
Interrupt 0x10 ax=0x4f15 bx=0x1 cx=0x0
Function supported
Call failed

The EDID data should not be trusted as the VBE call failed
ERROR: output block unchanged
I’m sorry nothing was successful.

Not sure if that means it’s an EDID issue or not... I’ll also open it up again and check the LVDS cabel.

Thanks again for the advice

[RealBlackStuff]

Most of those LTN141P4 screens were made for older machines like T30 and did not have any EDID.
You got the right screen, but without the EDID chip that your T60 needs.
Return it for one with an EDID.

[unixed]

Besides read-edid you can also use sysfs to check the EDID, but likely the panel does not have it. Use the appropriate hardware maintenance manual (HMM) from the link at the top of this page for the FRU for the panel and buy one with that label.

[kfzhu1229]

Most of those LTN141P4 screens were made for older machines like T30 and did not have any EDID.
You got the right screen, but without the EDID chip that your T60 needs.
Return it for one with an EDID.

I thought screens from T30 have the proprietary 40pin connector that doesn't even fit on T4x/6x at all. But yeah if you use a SXGA+ A3x screen or T4x screen you may run into issues.
To see if your screen has EDID, you can look at the datasheet and see if the first few pins that are supposed to be EDID 3.3V and 2 data pins whether they are connected at all. If you have pic of the back of the screen see if there is an 8 pin EDID chip beside the connector.

[benevans]

Ah ok so I should have been more careful. I assumed any 14.1-in. SXGA+ would work. I’m looking at the Hardware Maintenance Manuel and for SXGA+ it lists three FRUs: 13N7059, 13N7061 and 13N7063. The sticker on the back of mine says the FRU is 92P6770 so it seems this one doesn’t have the EDID chip the T60 needs.

This is unfortunate because I’ve had a quick look online at it seems a compatible screen is going to be difficult to source. I guess I’ll just put the original screen back in, though it’s a bit too dim for me to want to use often.

But thanks again for the help, at least I know what’s wrong with it now.

[RealBlackStuff]

Closest FRU I could find is 92P6760, which is an 14.1" SXGA+ screen for the T43 (which has no EDID).
Not sure if 92P6770 even exists...

[unixed]

Searching for the screens corresponding to those listed by FRU in the HMM is a safe option but you are not limited to them; the forum is rife with members upgrading screens for many models. What is important is that the pinout is correct. While it is good to independently verify that, you can just search the forum to find the models favoured by members. In this case (14.1" SXGA+) many like one with great specs except for the viewing angles by QDI, for example.

[benevans]

Searching for the screens corresponding to those listed by FRU in the HMM is a safe option but you are not limited to them; the forum is rife with members upgrading screens for many models. What is important is that the pinout is correct. While it is good to independently verify that, you can just search the forum to find the models favoured by members. In this case (14.1" SXGA+) many like one with great specs except for the viewing angles by QDI, for example.

Thanks for this tip, that’s actually very helpful. I’ll browse the forum and look into some more options.