Thinkpads Forum

Dear ThinkPad community,

I laid my hands on a W701 ThinkPad with a defective LCD screen.

To replace the cracked LCD I bought a new one (at laptopscreen.com) with matching FRU no’s and Lenovo P/N provided by the website (a 17” WUXGA RGB-LED backlit LCD from Samsung).
The received display does show some discrepancies in the part number, but only the last 2 digits of the Samsung P/N.
No FRU numbers were shown on the LCD unit since it was not specifically produced for Lenovo.
The original WUXGA display lit up and worked (but due to the crack and possible other damage it showed little working pixels).

The new screen that I built in did not work when tested, the following problem appeared:

When powered on with new display connected, the laptop starts and then powers off after 2 seconds. Its internal power circuit blocks all power and must be reset by removing the AC adapter and the battery before another attempt can be made. (No AC LED indicator on)

When re-attaching the original LCD unit the same problem occurs!!! The W701 does not longer accept the old original screen unless the old screen was damaged even further after removal.
When the screen cables are detached (no displays attached at all), this also occurs…
However, when an external display is connected (in this case via VGA) the system works perfectly (I’m typing this post on the W701 right now).

I also got the system to work with one (of the 2) cables attached to the LCD in combination with an external monitor. I expect this cable to be for colour calibration of the RGB LED backlight via colorimeter??

When I connect the LVDS connector it falls back in the issue I just described (with external display still attached).

Is there anyone out there familiar with this kind of issues considering LCD replacement? Any useful information is welcome.
High resolution pictures are available, see link below.
Thank you, your help will be appreciated.

Photos:
https://www.flickr.com/photos/allard-ph ... 529809823/

N.B.
Before you ask….
I checked my AC, and the LCD cable is connected properly connected and is undamaged!

Your new panel blew the fuse on the motherboard.

Try checking out the fuses with a multimer, the one that shows "open" is the one that needs to be replaced, or had another fuse soldered over it "piggy back" style.

Return the LCD and do NOT buy another one that doesn't have a FRU number on it.

Good luck.

Thanks for the reply,

I am returning the new LCD currently, hopefully these guys can provide me the right FRU labled panel.

Fuses is something I did not think of first.
From what I read, broken fuses are more often related to backlight issues rather then no display at all.

I will look further into it, but for this moment I have no idea how many and where those fuses are located.

Gynthar357 wrote: From what I read, broken fuses are more often related to backlight issues rather then no display at all.

When dealing with a LED-lit panel it's incredibly easy to blow a fuse.

I will look further into it, but for this moment I have no idea how many and where those fuses are located.

I'm sorry to say that I can't offer guidance in this respect, since I've never gutted out a W70* system.

The very best of luck to you.

What you should have done before plugging in anything is to look for the datasheets of the original and replacement panels.

Even if they have the same connector, they may have different pin layouts.

For example, in the Thinkpad X60/X61 series, one of the FRU LCDs is the Samsung LTN121XJ-L07.
The LTN121XJ-L03, however, is not compatible, and should not be plugged in.

A look at the pin layout shows why:
Pin # L07 L03
1 Ground +3.3v
2 +3.3v +3.3v
3 +3.3v Ground

As you can see, when the L03 is plugged in, it will short the +3.3v power line to Ground, which will blow a fuse on the laptop's system board.

The following numbers are on the backs of the screens:

old one:
LTN170CT8
6CAF03204L L01

New one:
LTN170CT08
6CAD06306D D05

when I google the LTN numbers, 5 results show up from 'Ali express'. The first one with the exact Lenovo FRU and P/N on it. out of stock though, and no datasheet.

It has the Same LTN number as my new screen.
the second number is different from both old and new screen.
but does end on L01 as the old screen.

As you can see, when the L03 is plugged in, it will short the +3.3v power line to Ground, which will blow a fuse on the laptop's system board.

It looks like the the new screen i received based on on my machine type is incompatible.
The mismatch in the numbers D05 and L01 could point to a similar case, maybe it's same problem.
In anyway the fuse could very well be blown by a short due to wrong replacement part.

The seller on Ali express Mentions that it should replace a Dell Precision M6400 screen.

On my new screen there is, instead of a FRU a number DP/N:0J501T Which leads to a Dell Precision M6500 screen.
This has the same LTN numbers as the Lenovo ones. but different sub type numbers (Lxx, Dxx).

This could mean that the place I bought the screen assumed they were exchangeable for Dell panels, and shipped me a M6500 panel.
The website specializes in Dell service i believe. when I made a support ticket i noticed that for Dell tickets a Dell service-tag was asked specifically.

All W701 2500-2Lx WUXGA laptops share the same LCD FRU: 42T0787

Gynthar357 wrote: I also got the system to work with one (of the 2) cables attached to the LCD in combination with an external monitor. I expect this cable to be for colour calibration of the RGB LED backlight via colorimeter??

When I connect the LVDS connector it falls back in the issue I just described (with external display still attached).

Hello.
You can see this specs ftp://helpedia.com/pub/temp/datasheets/ ... BDS%5D.pdf for lenovo's LCD. I don't find any specs for Dell's variant.
I want to belive that it is a blown fuse because functionality is not restored by connecting the old LCD. Other thing - is EDID (small memory chip in LCD) information about screen model and it's characteristics. When i've made QXGA mod (on T61) IAQX10N haven't correct EDID information so Thinkpad starting with corrupted image (color vertical lines). In your case it can't start at all

Couple offtopic questions.
Is it T60 on 16 photo?
Is it a wounded W701 behemoth from German ebay?

Thank you for providing the link to the datasheet.

unfortunately i was not able to read any LCD error information sins it powers off so quickly, so i got nothing on the EDID.
Hopefully it's just a fuse instead of more internal damage.

Is it T60 on 16 photo?

It's a T60p, well spotted.
Used it to display the HMM during the swap.

Is it a wounded W701 behemoth from German ebay?

Yup, the one with the LCD crack.

is LTN170CT08 the same as LTN170CT8 or are they different are both compatible with the w701

will LTN170CT08-L01 will that work on a w701
.

ajkula66 wrote:Your new panel blew the fuse on the motherboard.

Try checking out the fuses with a multimer, the one that shows "open" is the one that needs to be replaced, or had another fuse soldered over it "piggy back" style.

Return the LCD and do NOT buy another one that doesn't have a FRU number on it.

Good luck.

Does anyone know what fuse this is, I bought an LCD screen and with the correct part number on their ebay listing but the item sent had one number off. Now my w701 won't boot. No power at all.

Hello!

It's a big green fuse F19 near the LVDS on the _bottom_ side of the board, through it goes 20V to LED backlight.
It's parameters are 3A 32V.
It's better to replace it, of course, you can just solder a wire there (but only if you know what you're doing).

If its blown, the system will boot with external display, but even if you attach just cable without LCD it powers down.

There are also 3.3V LCD supply power fuse F20, but it's really less likely to be blown.

Regards

RogerAndOut wrote:Hello!

It's a big green fuse F19 near the LVDS on the _bottom_ side of the board, through it goes 20V to LED backlight.
It's parameters are 3A 32V.
It's better to replace it, of course, you can just solder a wire there (but only if you know what you're doing).

If its blown, the system will boot with external display, but even if you attach just cable without LCD it powers down.

There are also 3.3V LCD supply power fuse F20, but it's really less likely to be blown.

Regards

Thanks so much.

RogerAndOut wrote:Hello!

It's a big green fuse F19 near the LVDS on the _bottom_ side of the board, through it goes 20V to LED backlight.
It's parameters are 3A 32V.
It's better to replace it, of course, you can just solder a wire there (but only if you know what you're doing).

If its blown, the system will boot with external display, but even if you attach just cable without LCD it powers down.

There are also 3.3V LCD supply power fuse F20, but it's really less likely to be blown.

Regards

I had some time today and tried this, with and without the lcd cable connected. I only got the think light to blink ever few seconds and when it the blinks the cpu fan moves about a 1/2- 1 turn, no beeps or audible noise. I've attached video cable to the vga port and to the dvi port with the same result. I'd be happy to get it to POST and work with an external monitor. Thanks

If anyone in Southern California has expertise in this or can recommend a place that has expertise in something like this. Please let me know. Thanks

Sadly I destroyed my W701 on the same way today. I own a W701 with a broken display. Ordered this one:

http://www.ebay.de/itm/351611360238

It is also a LTN170CT08 panel but without FRU. Attached the panel, startet it - shutdown after 2-3 seconds. Now I have to say, that I am really bad in soldering. But I have some guys in german thinkpad-forum, which are great doing such repairs.
Has anybody successfully change the fuse on the board? Is it the F19 fuse? Or the F20 too?

Would be great to receive a positive answer here - I am really desperate in this case.

Thanks, regards,

XStoneX

I never got around to fixing it. I got one of ebay and upgraded everything, 32gb ram, 920xm the works and I ran into a pretty dishonest ebay seller screens. Never got it fixed one day when I have time I'll but right now it seems too time consuming.

@XStoneX:
that seller sold you a "compatible" screen, not the real deal.
Beware of any sellers using the word "for" in the description, and always read the small print!

browngranite wrote:LAPTOP LCD SCREEN FOR LENOVO...

Customer will receive a LCD screen from screen manufacturers, with matching specifications to fit the existing laptop.

As for (easier) fuse-repairs:
either solder the new fuse piggyback-style on top of the old one,
or solder a small wire to each end of the dead fuse and solder the new fuse between the other wire ends.
Tape that up to avoid shorting it.

Thanks for your answers.

Today it's getting totally weird. I received another mainboard for my W701 and I bought a original Panel FRU 42T0787. I changed both a wanted to start it - but I just have the same issues again!!!
I can't understand whats going on here. I've tried to change several things:

- graphic card
- display cable
- connected the old (broken) original display

No difference. The system won't boot. The only way to get my W701 startet is to disconnect the display cable on the mainboard and start it with an external monitor. Then it rocks solid. What the hell is going on here? The only logical answer for me is that I've received a defective mainboard. Bought it on eBay from a seller with 99,9% positive feedback:

http://www.ebay.com/itm/141184680160

Any other ideas? I don't have any ideas left...

Greetz,

XStoneX

I bought the W701 from XStoneX and was able to fix it by replacing two blown fuses, as was suggested by RogerAndOut in this thread: F19 and F20.

If the fuse F20 (power for the lcd panel) is blown because of trying to use the wrong version of the LTN170CT08 panel without FRU (and therefore with a different pinout), the thinkpad will not start with the lcd cable attached (no matter if a display panel is attached to the cable or not). I have no idea why this is the case.

For the fuse locations, see this picture (1024x608, 185.48 kB): http://abload.de/image.php?img=boardrepairw701rxkiq.jpg