Wednesday, December 17, 2008

Dell Latitude D800 Dead Display

Hey everyone, here are my notes on replacing the display inverter on a Dell Latitude D800. I'm not a repair tech and know enough to get in trouble. Hopefully this posting will help prevent you from doing the same!

The problem: Dell Latitude D800 display suddenly quit. After having developed the vertical line problem (and partially being repaired by Dell) the vertical lines stabilized and didn't get worse. But, the display did suddenly fail.

Step 1 - Consult Dell's support website and get the service manual.

Here, I booted the laptop with the 'fn' key depressed to put it in an autodiagnostic mode. After a period of time, it started beeping a morse code that can be decoded by using Dell's support website.

The answer was: Bad display inverter. I didn't know what that was.

Step 2 - Find replacement part on E-Bay and figure out if the laptop is worth repairing. This is the part, and it cost $20 bucks with expedited shipping. The one I found was used, but hey, its a used laptop.

Here is what was advertised and what was received. Not bad!

Dell Latitude D800 LCD Inverter LP154W01-B3 YPNL-N015A

Step 3 - Prepare the work area! I used a bathroom towel to help prevent parts from getting lost. This technique IS NOT good ESD practice, but this is not an expensive part and there are a bunch of small screws that have to be managed.

Step 4 - Follow the Dell Latitude service manual exactly as it states to prepare the laptop for display removal. But there were some specific experiences that I had that are important to point out.

a) I was hoping to keep the laptop plugged in as a ground, but the manual recommended against it. So instead, I just used my Bass (which delivers excellent static shocks) as a grounded metal surface to frequently touch before manipulating the laptop.

b) The service manual suggested removing the HDD, Memory and other expansion devices. This was not necessary to remove the display, therefore I left those parts alone.

c) Don't forget to remove the battery - the manual states clearly that in no way should the laptop be powered.

d) The manual suggests having a plastic scribe to work parts apart, etc... I found a big nylon tie to be effective and rigid enough. Definitely don't use a screwdriver to pry plastic - the Latitude's plastic is super easy to scratch and break (as you will see below)

Step 5 - Laptop prepared, now after the Display Inverter!

The service manual will have a section on how to remove the display. Follow it. You must first remove the two screws that hold the display in place.

The first thing I encountered was having to remove the main control panel cover. This thing is super flimsy and clearly is easy to break as it is being worked off the main part of the laptop. In particular, the area where the control panel meets the LEDs for power, disk and charging appears very easy to break. Be careful.

On the left side is a recessed notch that can be used by the plastic scribe to pop it out.

The service manual suggests putting the display back 180 degrees - this is actually necessary as the control panel cover cannot be removed safely with the display in the upright position.

Note the circled areas - good tab points to work.

When the control panel cover comes off, don't pull it away. It is connected by a ribbon cable on the far right.

Finally, observe the EMI clip and how the display cable runs under it. You probably want to place it back in its proper position when reassembling. Note in the picture that the display cable has been disconnected.

Step 6 - Free the display from the laptop

Again, following the service manual instructions, you will be lifting the display off the laptop chassis now that the control panel cover has been removed.

In doing this, I carefully lifted it away. The trick here is to not have the display hinges catch the control panel cover which is still wired to the laptop. Two people would work best.

Step 7 - Disassembling the display

This is where things got ugly. First off, the service manual isn't clear about which bumpers to remove. Don't remove the oval bumpers on the sides of the display - there is no screw behind them.

Here is how you can use a nylon cable tie to pop out the bumpers while not marring the plastic surface.

When following the service manual on removing the screws to release the bezel, take note that the two center lower screws are different from the other six 2.5x6mm screws.

With all of the screws removed from the display assembly, the major task is at hand: remove the bezel. This is the most difficult aspect of the repair.

Carefully read the service manual on recommendations from removing the bezel off the display and laptop cover (made of metal).

The bezel is extremely flimsy and can break!

Here is why I broke it - I didn't know which way to work the bezel and lifted up too strongly. What is going on is that the display and laptop cover have hooks that point inward. Consequently, applying force against the outer bezel edge inward toward the display is best to work the bezel off.

Here is a detail on the hooks. This picture shows the bezel on the left which is the part that is to come away from the display and laptop cover.

Here is a detail on the hook that is attached to the display and laptop cover. Note that although it appears that the hook will release the bezel if an upward force is applied to the bezel, this is untrue. If the bezel is pried away from the display and laptop cover, the bezel loops that these hooks catch will break.

Push the bezel edge inward, and use the plastic scribe to apply a gentle upward force.

The bezel really isn't designed to be removed.

Finally, the laptop cover hook that is attached to the display is attached to the display and laptop cover. The hook is NOT attached to the bezel, it is of no use in removing the bezel other than to stabilize the display and laptop cover as the bezel is removed.

Here are the latches on the display case where the bezel really needs to be worked.

The last part of this step is to realize that there are three screws on the right hand side that should not be removed. Here they are two of them. The screws that should be removed are tiny and are in the plane of the LCD.

Step 8 - Smooth sailing from here on out!

You are replacing the display inverter, and the connectors, remaining screw and component replacement is obvious and the service manual effectively describes what needs to be done.

But at this point, there were serious issues with my display!

First, it appears as if a ground was not properly attached to the laptop cover. Can't be too careful with these things especially in noisy electronic environments. Perhaps when the display was in for the vertical line problem this connection was detached? Doubt it, it would have just been cut.

Second, wires were pinched and wire exposed! No wonder this thing failed. Leaking current, no ground, wtf.

Here are the repairs made after the inverter was replaced.

Fixed ground wire.

Repaired and routed the wires.

Step 9 - reassemble and enjoy!