ThinkPad T4x LCD cable mod

[kfzhu1229]

Is there anyone else here whom have done a LCD cable mod to change screen resolutions on the T4x and R5x computers?
I was thinking, since T4x/R5x computers use some jumpers on their LCD cable assembly to determine the screen resolution, maybe I can also change that a bit so that when I upgrade from XGA to UXGA (or SXGA+), I don't have to buy a whole other cable to do so.
Well, turns out this is much easier on the 14.1" models, because the 14.1" models use actual 0 ohm resistors to config the resolution, while the 15" models use hole punchers to disconnect certain wires to config the resolution.
Today I successfully turned a 91P6826 R51 15" XGA cable into a 15" UXGA cable by severing one trace of connection and shorting a trace of connection.
I wonder if anyone else in this forum does such a thing.

[axur-delmeria]

I've read of such mods before, probably on this very forum. Try the search function.

[kfzhu1229]

Well, it is just that I see no users mention about anything like this in this forum, so I ended up figuring everything from scratch! It is not a hard thing to do, but if you mess up, you have to order the new cable (better be the higher resolution one), and wait for the thing to arrive while you use your ThinkPad as a halftop.

[Qcraft123]

hey, could you please share what connections you had to change on the cable to make it SXGA?

thanks

[kfzhu1229]

hey, could you please share what connections you had to change on the cable to make it SXGA?

thanks

This depends on the screen size. for 14.1" it is easy enough. The jumpers are just 0 Ohm resistors soldered onto the connector on the motherboard end. For 15" you have to physically cut traces and solder traces, thus much harder to do. Tell me which dimension of screen you have and I will send you the configuration.

[Qcraft123]

it is the 14.1" one

thanks

[kfzhu1229]

it is the 14.1" one

thanks

Here are the differences for the 14.1" models:
https://imgur.com/a/RCiUXzx
Just moving the 0 Ohm resistors to the new location should do the job, though do that at your own risk!
Good luck!
EDIT: 14.1" SXGA+ image here: https://imgur.com/a/i8gTVXK

[Qcraft123]

Thank You! it works perfectly

[kfzhu1229]

I will do an update to this thread for the 15" models. From an UXGA panel sale I did recently here, I found out that:
1. Apparently 15" XGA T4x and R5x have different jumpers, but is inter-compatible.
2. Unlike my previous experiment with the R5x cable, with 15" T4x XGA cable, it is REALLY easy to mod it into UXGA.
See the picture of a T4x 15" XGA cable here:
https://i.imgur.com/c2qTBGY.jpg
Notice there is a hole punched on the trace connecting to the second leg of the connector from the left, that is the jumper setting for T4x 15" XGA. Luckily, the jumper setting for T4xp 15" UXGA also have that hole punched on that same trace, and the only difference is another hole punched on the trace immediately on the right side of that trace with a hole punch, and connects to the 3rd leg of the connector. Thus if you take a needle and heat it up to plastic melting temperature, and use the hole opening to melt and disconnect the trace on the right side, you get UXGA resolution on a XGA cable! I verified that it worked for 15" T4x on a T60p UXGA LCD just like it did on the R5x with extra work. This potentially saves a lot of money on UXGA upgraders.
Now it would be interesting to see if you can do a similar mod to get XGA cable to work with QXGA. But this is gonna require a picture of the R50p QXGA cable.
https://1drv.ms/u/s!At7-rt1KJ7WviPU1jJO ... Q?e=tqa0XB

[olex126]

I have an R50p QXGA cable boxed up here somewhere.

If you need a full set of pics, I can do some up on Saturday and post them.

Alternatively, I could probably just sell you the cable and you could take your own pics

Regards.

Dave

[kfzhu1229]

I have an R50p QXGA cable boxed up here somewhere.

If you need a full set of pics, I can do some up on Saturday and post them.

Alternatively, I could probably just sell you the cable and you could take your own pics

Regards.

Dave

Actually I don't even have anything that is QXGA so no I cannot make use of it in any way. BUT for the fellow users that want a QXGA screen in their T4x, this enables them the option to do so without forcing a R50p cable into the T4x body.
Anyways, what I need a clear picture of (at the location of the connector that connects to the motherboard) is:
1. the top side
2. the bottom side, please angle it so that it includes the front side that faces towards you when the connector is seated
A sample of the kind of image that I want (Taken from my UXGA cable and a XGA cable modded to UXGA):
1.
https://1drv.ms/u/s!At7-rt1KJ7WviPUtxDQ ... w?e=yHUAFN
2.
https://1drv.ms/u/s!At7-rt1KJ7WviPU1jJOfAZJHm3ToyQ
This will clearly allow us to see the differences in the locations where the holes are punched onto the traces, so we know what traces to cut and what trace to connect. Fingers crossed that it won't be ridiculously hard!
EDIT: I think I might as well make my idea clear: from the picture below, I labelled the first 5 pins of the connector as 1, 2, 3, 4 and 5. For 2-5, if the trace isn't cut, it is connected to 1, otherwise it is disconnected to 1.
So here is a list of known observations for 15" T4x/R5x:
R5x XGA (The one pictured below): cut pin 3, 4
T4x XGA: cut pin 2
T4x UXGA: cut pin 2, 3 (which makes XGA to UXGA extremely easy)

For example, if you want to convert a T4x XGA cable to UXGA, you just cut pin 3; if you want to convert a R5x XGA cable to work with UXGA, you connect pin 4 and cut pin 2, which is a lot more troublesome, but I have verified both working.

https://1drv.ms/u/s!At7-rt1KJ7WviPVS73U ... A?e=XW5qcf

[olex126]

The photos/micro-photos of the R50p QXGA cable are finally posted.

Link: https://s186.photobucket.com/user/olex1 ... 837?page=1

Hope they help. Let me now if you require any different angles or magnifications.

Regards.

Dave

[kfzhu1229]

Spent an entire day trying to get the QXGA mod to work, but from the looks of it, it did!
From the pictures of the QXGA cable (Thanks a lot, fellow Canadian olex126!), it seems like the QXGA configuration is to have all of pin 2-5 (From the top left) connected to pin1. So I took a spare XGA cable and tried to connect pin 2 (and fix my previous mod failure) and it worked! The BIOS screen is no longer in XGA resolution and Windows detects a recommended resolution of 2048*1536 QXGA!
The best thing is, you don't even need a T43p to get it working - it worked on my T43 with Radeon X300 as well! (the pictures running Windows 8.1 Chinese are from my T43 and Windows 7 is from my T43p)
https://1drv.ms/u/s!At7-rt1KJ7WviPVTNCL ... w?e=X15lrC
Now the thing is I definitely do NOT have a QXGA panel, so I can only plug in my labrat XGA screen to see if BIOS and Windows tries to push 2048*1536 on there.
So would someone please test this mod configuration out on a 15" T4x XGA cable with a T6x QXGA screen and see if it really works there? Again the mod is to connect the second pin from top left (where on the XGA cable there is a hole punch on the only trace connected to it) to any adjacent pin (the pins on either side are connected with each other).

[kfzhu1229]

Well the last piece of puzzle to this project is I am missing the configuration for 15" SXGA+ IPS configuration. Well today I have a 15" SXGA+ panel savaged from a dead laptop that I wanna try to fit inside my T43.
From what I see on eBay listings for FRU 91P6892, I can make out there is a hole on the top side, but I do not know if there are any more on the bottom.
So can someone who own this FRU or its non-ROHS counterpart 91P6857 help me by sharing me a photograph of the bottom of the cable so I can see if there are any holes there?
Thanks for your help.
Also on a side note, the 15" SXGA+ IPS configuration works on a T43 with iGPU right?

[ajkula66]

Also on a side note, the 15" SXGA+ IPS configuration works on a T43 with iGPU right?

Yes

[kfzhu1229]

Okay so I have gotten it to work with the guesswork that I have. I used this picture from a listing on eBay and if you zoom in you see a hole punched on the trace connected to the 3rd pin from the top left. Thankfully that's also the only trace that's punched.
So for 15" T4x from XGA to SXGA+, it is a bit complicated and involves with connecting the punched trace on the XGA cable and disconnecting the trace on the right side of it.
https://i.ebayimg.com/images/g/rIMAAOSw ... -l1600.jpg

However getting that screen to work was much more complicated than I thought.
So first I connected that XGA cable as is to SXGA+ thinking it would at least display some picture, it displayed just a black screen. I would normally try UXGA but trying that results in that iGPU mobo displaying a random resolution. I first thought my screen was broken but then I realised that I got the exact same problem when I connected a WUXGA screen to a single channel LVDS cable. And sure enough I measured the 2nd channel there are no voltage whatsoever.
So I went for broke and connected that trace and disconnected the other trace using a tiny sliver of Kapton tape (electrical tape has too much friction) going on top of that pin. That worked!
However the first roadblock is the connector location is not the same. If you see the picture of auo b150pn01, you see the connector is on the far right side from the back, so I folded the cable at 2 places to accommodate for that and forget about the Thinklight.
Then once again I have the problem where the mounting holes are at the wrong position and has to settle with taping the brackets on instead!
I have to also undo the 90 degree fold on the inverter connector just so that it actually BARELY reaches into its slot!
Then I just shoved the bezel on top and thankfully it's all fully working.
So, my AUO B150PN01 works on T4x (but not on T6x due to the lack of EDID) but at the cost of serious modding.
Still, I take that because I got this screen off a junk ECS branded (tiny branded) laptop. The rest go on feebay at a cost to cover its fees and postage or straight to e-waste.

Then I just want to test whether the full SXGA+ resolution is fully recognised in Windows, and this is where I found another roadblock:
I used Windows 2000 and XP installations from my T42 and my ATI based T43, all of them give the 0x7B inaccessible boot device at startup!
I then tried the XP installation from the 845GM chipset Latitude D400, got the NTLDR not found error.
Ironically, then I tried a copy of Windows 7 installation also for the D400, that worked! But fiddling around with the crap iGPU driver in Windows 7 was not fun at all...
So does the intel version of the T43 have a totally different hard drive controller than the other T43 versions that cause this issue?

[ajkula66]

So does the intel version of the T43 have a totally different hard drive controller than the other T43 versions that cause this issue?

No.

I remember swapping drives back and forth between ATi/Intel units many times back in the day. This was XP era, can't say that I recall much of anything regarding W7 on an Intel-based T43 although I remember playing with that setup.

[RealBlackStuff]

So does the intel version of the T43 have a totally different hard drive controller than the other T43 versions that cause this issue?

Correct answer is YES.
AFAIK all R52/T43/T43p with ATI GPU use the Marvell 88SA8040 SATA-PATA bridge.
But some (or all?) R52/T43 with Intel GPU use the Silicon Image Sil3811 SATA-PATA bridge.

(And T42 chipsets are also quite different from T43 chipsets.)

[ajkula66]

AFAIK all R52/T43/T43p with ATI GPU use the Marvell 88SA8040 SATA-PATA bridge.
But some (or all?) R52/T43 with Intel GPU use the Silicon Image Sil3811 SATA-PATA bridge.

And I still learn new things from you...