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Upgrading a T400
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suddenthinkpadenthusiast
- Posts: 13
- Joined: Tue Feb 02, 2021 10:45 pm
- Location: Saratoga, CA
Upgrading a T400
My neighbor recently threw out a T400 in near-factory condition, and I picked it up. Given the fact that the battery reports only 21 charge cycles and that the chassis has literally zero scratches, I'm pretty sure it was used as a desktop replacement (the only evidence I found of use was dust).
It seems to be a base model with a Core 2 Duo P8400, a 500 GB 7200 RPM WD Black HDD, 1280x800 display, and no discrete graphics (that's okay because I don't plan to use anything that requires 3D).
I've already given it some under-the-hood upgrades by replacing the CPU with an E8135 I salvaged from an old iMac (T9550 equivalent), maxxing out the RAM, installing a 120 GB SSD, and flashing a modified BIOS to remove the network card whitelist. I really, REALLY love the keyboard as well, but I'll use an external keyboard more often to keep it pristine.
I'm quite interested in upgrading the display and installing a second battery via Ultrabay. Does the T400 use a CCFL or LED backlight, and are there any good displays compatible with it? Is there a better source than eBay for Ultrabay Slim batteries, and are there any other modifications I should do? The best listing I found was for only a used secondary battery. Also, are there any other upgrades or modifications I should do to my T400? Thanks so much for your help!
It seems to be a base model with a Core 2 Duo P8400, a 500 GB 7200 RPM WD Black HDD, 1280x800 display, and no discrete graphics (that's okay because I don't plan to use anything that requires 3D).
I've already given it some under-the-hood upgrades by replacing the CPU with an E8135 I salvaged from an old iMac (T9550 equivalent), maxxing out the RAM, installing a 120 GB SSD, and flashing a modified BIOS to remove the network card whitelist. I really, REALLY love the keyboard as well, but I'll use an external keyboard more often to keep it pristine.
I'm quite interested in upgrading the display and installing a second battery via Ultrabay. Does the T400 use a CCFL or LED backlight, and are there any good displays compatible with it? Is there a better source than eBay for Ultrabay Slim batteries, and are there any other modifications I should do? The best listing I found was for only a used secondary battery. Also, are there any other upgrades or modifications I should do to my T400? Thanks so much for your help!
Last edited by suddenthinkpadenthusiast on Wed Feb 03, 2021 1:51 pm, edited 1 time in total.
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axur-delmeria
- Senior ThinkPadder

- Posts: 4413
- Joined: Mon May 28, 2012 5:49 am
- Location: Metro Manila, Philippines
Re: Upgrading a T400
The T400 can use both CCFL and LED-backlit screens-- these require different LCD cables and inverter cards. The T400 Hardware Maintenance Manual has disassembly instructions and parts lists.
Here's a list of T400 LCDs, taken from http://thinkwiki.org/wiki/TFT_display:
14.1" 1280x800 CCFL
AUO B141EW04 V.1
CMO N141I3-L03
LG-Philips LP141WX3-TLR1
Samsung LTN141W1-L05
14.1" 1280x800 LED
Samsung LTN141AT09
LG-Philips LP141WX5-TLP2
14.1" 1440x900 CCFL
LG-Philips LP141WP1-TLB8
Samsung LTN141WD-L05
AUO B141PW03
14.1" 1440x900 LED
LG-Philips LP141WP2-TLB1
Samsung LTN141BT04
Samsung LTN141AT12 apparently 1280x800
Here's a list of T400 LCDs, taken from http://thinkwiki.org/wiki/TFT_display:
14.1" 1280x800 CCFL
AUO B141EW04 V.1
CMO N141I3-L03
LG-Philips LP141WX3-TLR1
Samsung LTN141W1-L05
14.1" 1280x800 LED
Samsung LTN141AT09
LG-Philips LP141WX5-TLP2
14.1" 1440x900 CCFL
LG-Philips LP141WP1-TLB8
Samsung LTN141WD-L05
AUO B141PW03
14.1" 1440x900 LED
LG-Philips LP141WP2-TLB1
Samsung LTN141BT04
Samsung LTN141AT12 apparently 1280x800
Last edited by axur-delmeria on Wed Feb 03, 2021 9:45 pm, edited 2 times in total.
Planned Purchase: T480s i5-8350 FHD Touch
Impulse Buy: Thinkpad not named for safety reasons
RIP: X220 4291-C91 X61 7676-A24 760XD-U9E
Impulse Buy: Thinkpad not named for safety reasons
RIP: X220 4291-C91 X61 7676-A24 760XD-U9E
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suddenthinkpadenthusiast
- Posts: 13
- Joined: Tue Feb 02, 2021 10:45 pm
- Location: Saratoga, CA
Re: Upgrading a T400
axur-delmeria wrote: ↑Wed Feb 03, 2021 12:55 amThe T400 can use both CCFL and LED-backlit screens-- these require different LCD cables and inverter cards. The T400 Hardware Maintenance Manual has disassembly instructions and parts lists.
Thanks for letting me know! Is there any sort of non-invasive procedure I can use to determine my display backlight, and are there any noticeable differences in external appearance? I don't want to unnecessarily pry open the display assembly and risk damaging the plastic. Also, LED backlights are more efficient than CCFLs, right?
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RealBlackStuff
- Admin Emeritus
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- Joined: Mon Sep 18, 2006 5:17 am
- Location: Loch Garman, Éire
Re: Upgrading a T400
Programs like HWINFO show you exactly what LCD/parts you have.
LEDs run better/cooler than CCFL.
LEDs run better/cooler than CCFL.
Lovely day for a Guinness! (The Real Black Stuff)
But I actually prefer Murphy's from Cork!
But I actually prefer Murphy's from Cork!
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suddenthinkpadenthusiast
- Posts: 13
- Joined: Tue Feb 02, 2021 10:45 pm
- Location: Saratoga, CA
Re: Upgrading a T400
HWInfo64 shows that I have an LTN141AT12-M01, which corresponds to a 1440x900 display with an LED backlight. Oddly enough however, the Windows 7 display settings only report a maximum resolution of 1280x800, and I don't notice any blurring. Could this simply be a GM45 driver limitation, or is there something else going on?axur-delmeria wrote: ↑Wed Feb 03, 2021 12:55 amThe T400 can use both CCFL and LED-backlit screens-- these require different LCD cables and inverter cards. The T400 Hardware Maintenance Manual has disassembly instructions and parts lists.
Here's a list of T400 LCDs, taken from http://thinkwiki.org/wiki/TFT_display:
14.1" 1280x800 CCFL
AUO B141EW04 V.1
CMO N141I3-L03
LG-Philips LP141WX3-TLR1
Samsung LTN141W1-L05
14.1" 1280x800 LED
Samsung LTN141AT09
LG-Philips LP141WX5-TLP2
14.1" 1440x900 CCFL
LG-Philips LP141WP1-TLB8
Samsung LTN141WD-L05
AUO B141PW03
14.1" 1440x900 LED
LG-Philips LP141WP2-TLB1
Samsung LTN141BT04
Samsung LTN141AT12
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axur-delmeria
- Senior ThinkPadder

- Posts: 4413
- Joined: Mon May 28, 2012 5:49 am
- Location: Metro Manila, Philippines
Re: Upgrading a T400
Looks like Thinkwiki's data is incorrect. A quick search yields https://www.panelook.com/LTN141AT12-L01 ... 13090.html which states that it's 1280x800.
It seems that the "A" in LTN141AT12 (and LTN141AT09) denotes 1280x800 while the "B" in LTN141BT04 means 1440x900.
It seems that the "A" in LTN141AT12 (and LTN141AT09) denotes 1280x800 while the "B" in LTN141BT04 means 1440x900.
Planned Purchase: T480s i5-8350 FHD Touch
Impulse Buy: Thinkpad not named for safety reasons
RIP: X220 4291-C91 X61 7676-A24 760XD-U9E
Impulse Buy: Thinkpad not named for safety reasons
RIP: X220 4291-C91 X61 7676-A24 760XD-U9E
Re: Upgrading a T400
you must have got the video display drivers also.?. 1440 x 900 .which is the driver?
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suddenthinkpadenthusiast
- Posts: 13
- Joined: Tue Feb 02, 2021 10:45 pm
- Location: Saratoga, CA
Re: Upgrading a T400
It's been a while, but there's another question I have on this. I found a T400 with display LTN141BT04 (1440x900, LED backlight). Although it's a different resolution, is it drop-in compatible with LTN141AT12 (1280x800, LED backlight), or will I need to swap the inverter and everything else as well?axur-delmeria wrote: ↑Wed Feb 03, 2021 12:55 amThe T400 can use both CCFL and LED-backlit screens-- these require different LCD cables and inverter cards. The T400 Hardware Maintenance Manual has disassembly instructions and parts lists.
Here's a list of T400 LCDs, taken from http://thinkwiki.org/wiki/TFT_display:
14.1" 1280x800 CCFL
AUO B141EW04 V.1
CMO N141I3-L03
LG-Philips LP141WX3-TLR1
Samsung LTN141W1-L05
14.1" 1280x800 LED
Samsung LTN141AT09
LG-Philips LP141WX5-TLP2
14.1" 1440x900 CCFL
LG-Philips LP141WP1-TLB8
Samsung LTN141WD-L05
AUO B141PW03
14.1" 1440x900 LED
LG-Philips LP141WP2-TLB1
Samsung LTN141BT04
Samsung LTN141AT12 apparently 1280x800
Edit: Do LED backlights need an inverter? If I'm not wrong, the inverter is only present on CCFL models--the board on mine just has LEDs.
æ
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RealBlackStuff
- Admin Emeritus
- Posts: 24727
- Joined: Mon Sep 18, 2006 5:17 am
- Location: Loch Garman, Éire
Re: Upgrading a T400
LED screens have an LED-subcard, which is different from a CCFL-inverter.
LED screens usually also have different LCD-cables.
That LTN141BT04 should be a drop-in.
If you get the whole T400, check its LCD-cable also.
If needed swap it together with the LCD.
LED screens usually also have different LCD-cables.
That LTN141BT04 should be a drop-in.
If you get the whole T400, check its LCD-cable also.
If needed swap it together with the LCD.
Lovely day for a Guinness! (The Real Black Stuff)
But I actually prefer Murphy's from Cork!
But I actually prefer Murphy's from Cork!
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axur-delmeria
- Senior ThinkPadder

- Posts: 4413
- Joined: Mon May 28, 2012 5:49 am
- Location: Metro Manila, Philippines
Re: Upgrading a T400
No need to swap the inverter (or anything for that matter).suddenthinkpadenthusiast wrote: ↑Sat Apr 03, 2021 10:34 pmIt's been a while, but there's another question I have on this. I found a T400 with display LTN141BT04 (1440x900, LED backlight). Although it's a different resolution, is it drop-in compatible with LTN141AT12 (1280x800, LED backlight), or will I need to swap the inverter and everything else as well?
LED backlights do not need an inverter. In the T400 HMM, the "inverter board" is called a "LED subcard" for models with LED backlights. That part only contains indicator LEDs.suddenthinkpadenthusiast wrote: ↑Sat Apr 03, 2021 10:34 pmEdit: Do LED backlights need an inverter? If I'm not wrong, the inverter is only present on CCFL models--the board on mine just has LEDs.
Planned Purchase: T480s i5-8350 FHD Touch
Impulse Buy: Thinkpad not named for safety reasons
RIP: X220 4291-C91 X61 7676-A24 760XD-U9E
Impulse Buy: Thinkpad not named for safety reasons
RIP: X220 4291-C91 X61 7676-A24 760XD-U9E
Re: Upgrading a T400
A web search for "Thinkpad Battery 43" or the FRU (45N1041) should pull up a few options. Some of these might be "compatible" and not genuine, but new.suddenthinkpadenthusiast wrote: ↑Tue Feb 02, 2021 10:52 pmIs there a better source than eBay for Ultrabay Slim batteries, and are there any other modifications I should do? The best listing I found was for only a used secondary battery.
Thinkpad 25 (20K7), T16 Gen 3 (21MQ), Yoga 14 (20FY), T430s (IPS FHD + Classic Keyboard), X220 4291-4BG
X61 7673-V2V, T60 2007-QPG, T42 2373-F7G, X32 (IPS Screen), A31p w/ Ultrabay Numpad
X61 7673-V2V, T60 2007-QPG, T42 2373-F7G, X32 (IPS Screen), A31p w/ Ultrabay Numpad
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suddenthinkpadenthusiast
- Posts: 13
- Joined: Tue Feb 02, 2021 10:45 pm
- Location: Saratoga, CA
Re: Upgrading a T400
Okay, I just discovered something interesting. The daugterboard for LTN141AT12 actually has two ribbon cables leading to it--one looks like it's for LEDs, and the other one appears to be for an inverter (it leads to the edge of the display). The board also has some extra circuitry, so I'm guessing that LTN141AT12 is actually a CCFL-based display despite Thinkpad Wiki's suggestion that it's not. However, LTN141BT04 (which I swapped in and works fine) doesn't have a second ribbon cable. Strange.axur-delmeria wrote: ↑Sun Apr 04, 2021 1:03 amNo need to swap the inverter (or anything for that matter).suddenthinkpadenthusiast wrote: ↑Sat Apr 03, 2021 10:34 pmIt's been a while, but there's another question I have on this. I found a T400 with display LTN141BT04 (1440x900, LED backlight). Although it's a different resolution, is it drop-in compatible with LTN141AT12 (1280x800, LED backlight), or will I need to swap the inverter and everything else as well?
LED backlights do not need an inverter. In the T400 HMM, the "inverter board" is called a "LED subcard" for models with LED backlights. That part only contains indicator LEDs.suddenthinkpadenthusiast wrote: ↑Sat Apr 03, 2021 10:34 pmEdit: Do LED backlights need an inverter? If I'm not wrong, the inverter is only present on CCFL models--the board on mine just has LEDs.
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axur-delmeria
- Senior ThinkPadder

- Posts: 4413
- Joined: Mon May 28, 2012 5:49 am
- Location: Metro Manila, Philippines
Re: Upgrading a T400
If the second cable has two wires (probably colored white and pink) like this, then it's CCFL. But if it's a flat flex cable, then it's LED.
Most likely it's a transitional design: the large circuit board is probably the same as their CCFL model, and they just added a LED backlight driver board.
Most likely it's a transitional design: the large circuit board is probably the same as their CCFL model, and they just added a LED backlight driver board.
Planned Purchase: T480s i5-8350 FHD Touch
Impulse Buy: Thinkpad not named for safety reasons
RIP: X220 4291-C91 X61 7676-A24 760XD-U9E
Impulse Buy: Thinkpad not named for safety reasons
RIP: X220 4291-C91 X61 7676-A24 760XD-U9E
Upgrading a T400
Hi all . In this thread I wanted to expand the concept of updating the T400 so that everything was in one place. There is a very good article on completely updating the T440 https://web.archive.org/web/20231019205 ... ers-guide/, but I didn't find anything similar about the T400. If I understand correctly (correct or supplement me if I’m wrong), then the best decisions today will be .
Replacement :
1. Display
WXGA+ 14.1″ 1440×900 LCD Screen 42T0504 LTN141BT04 Grade A Manufacturer is probably better than “LG” or “Samsung”
https://www.panelook.com/LTN141BT04-002 ... 24142.html
And also replace a new cable for the LED screen and a new inverter
2. Memory. 8Gb (4 GB +4 GB) DDR3 Crucial or Samsung. As far as I understand, this is the maximum possible.
3. Remove DVD and replace with Optibay SSD Case Adapter
4. Replacing the HDD with an SSD will definitely significantly improve the loading of the operating system. Installing Gnu/Linux or OpenBSD.
5. CPU It’s good that the processor is removable and you can install a 4-core processor https://thonkpeasant.xyz/guides/other/quad.html
If there is anything else that can be replaced, please write..
Replacement :
1. Display
WXGA+ 14.1″ 1440×900 LCD Screen 42T0504 LTN141BT04 Grade A Manufacturer is probably better than “LG” or “Samsung”
https://www.panelook.com/LTN141BT04-002 ... 24142.html
And also replace a new cable for the LED screen and a new inverter
2. Memory. 8Gb (4 GB +4 GB) DDR3 Crucial or Samsung. As far as I understand, this is the maximum possible.
3. Remove DVD and replace with Optibay SSD Case Adapter
4. Replacing the HDD with an SSD will definitely significantly improve the loading of the operating system. Installing Gnu/Linux or OpenBSD.
5. CPU It’s good that the processor is removable and you can install a 4-core processor https://thonkpeasant.xyz/guides/other/quad.html
If there is anything else that can be replaced, please write..
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nicolontium
- Posts: 3
- Joined: Wed Feb 07, 2024 7:50 am
- Location: Leipzig, Germany
Re: Upgrading a T400
There are some other updated you can do.
1. Bluetooth 4.0 (easy)
The T400 comes with a Bluetooth daughter card (FRU 42T0969) which is only Bluetooth 2.1.
The daughter card is a plug in adapter but it requires dissembling the display.
However, if you replace the old adapter with the newer one (FRU 60Y3305) which was used, e.g., in the T430, you can add Bluetooth 4.0 functionality.
I did this with several other Thinkpads (although not with a T400 yet) and never had compatibility issues. There is no BIOS whitelisting for those Bluetooth daughter cards and they should all be compatible with each other.
Linux and Win 11 come with the drivers. For Windows versions 7/8/10 the drivers from the T430 can be used.
2. WiFi and WWAN (requires modded BIOS)
Another option would be to replace the WiFi and/or WWAN mini pcie cards with something newer (I use an Intel AX210 for my X201 - the mini pcie version and not the M.2).
But this requires a modded Bios with the whitelist removed.
Also newer WiFi adapters usually come with Bluetooth onboard (my Intel AX210 came with Bluetooth version 5.3) which might (or might not) be a problem for Windows OS.
At least in Linux you can use both Bluetooth adapters at the same time, or just disable one of them. Maybe this is also possible in Windows, but I haven't checked.
1. Bluetooth 4.0 (easy)
The T400 comes with a Bluetooth daughter card (FRU 42T0969) which is only Bluetooth 2.1.
The daughter card is a plug in adapter but it requires dissembling the display.
However, if you replace the old adapter with the newer one (FRU 60Y3305) which was used, e.g., in the T430, you can add Bluetooth 4.0 functionality.
I did this with several other Thinkpads (although not with a T400 yet) and never had compatibility issues. There is no BIOS whitelisting for those Bluetooth daughter cards and they should all be compatible with each other.
Linux and Win 11 come with the drivers. For Windows versions 7/8/10 the drivers from the T430 can be used.
2. WiFi and WWAN (requires modded BIOS)
Another option would be to replace the WiFi and/or WWAN mini pcie cards with something newer (I use an Intel AX210 for my X201 - the mini pcie version and not the M.2).
But this requires a modded Bios with the whitelist removed.
Also newer WiFi adapters usually come with Bluetooth onboard (my Intel AX210 came with Bluetooth version 5.3) which might (or might not) be a problem for Windows OS.
At least in Linux you can use both Bluetooth adapters at the same time, or just disable one of them. Maybe this is also possible in Windows, but I haven't checked.
Upgrading a T400
Hello . Thanks for the information, but I don’t use bluetooth https://en.wikipedia.org/wiki/Bluesnarfing (Bluesniping Bluebugging KNOB, etc.) there are other types of communication that are more reliable))
But I know there is a free solution: USB BLUETOOTH BLE 4.0 (CSR8510 A10) Adapter Depending on your distribution, it will work.
But I know there is a free solution: USB BLUETOOTH BLE 4.0 (CSR8510 A10) Adapter Depending on your distribution, it will work.
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nicolontium
- Posts: 3
- Joined: Wed Feb 07, 2024 7:50 am
- Location: Leipzig, Germany
Re: Upgrading a T400
Yes, I know what you mean. I don't use Bluetooth that often. But sometimes it is just convenient to use a wireless BT headset for online conferences and BT 4.0 just gives you a little more range compared to the BT 2.1 that was shipped with the older ThinkPads.
Sure, Bluetooth dongles work well. But to be honest, it is the modding that is fun and you can get a used BT daughter card for almost no money.
For the T400 I can now confirm that the FRU 60Y3305 BT 4.0 card works perfectly with the original bios.
I also tried to flash the modded bios from here
http://www.mediafire.com/file/0wug1m0vt ... L.zip/file
that was mentioned in a comment to this reddit post
https://www.reddit.com/r/thinkpad/comme ... _bios_mod/
Flashing worked fine, but I sill have to check if I now can use non-whitelisted WiFi and WWAN cards.
I have a spare Intel AC 7260HMW (FRU 04X6010) which I will check out soon.
Sure, Bluetooth dongles work well. But to be honest, it is the modding that is fun and you can get a used BT daughter card for almost no money.
For the T400 I can now confirm that the FRU 60Y3305 BT 4.0 card works perfectly with the original bios.
I also tried to flash the modded bios from here
http://www.mediafire.com/file/0wug1m0vt ... L.zip/file
that was mentioned in a comment to this reddit post
https://www.reddit.com/r/thinkpad/comme ... _bios_mod/
Flashing worked fine, but I sill have to check if I now can use non-whitelisted WiFi and WWAN cards.
I have a spare Intel AC 7260HMW (FRU 04X6010) which I will check out soon.
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