Display <> inverter interchangeability?

[keithsketchley]

Can anyone please advise if the inverters are interchangeable?

The HMM, such as it is, shows two p/ns of display and more than that of inverters. My x41 has the 27K99993 by Ambit, haven't yet figured out which display it has.

Thanks....Keith

[keithsketchley]

I add that from photos on eBay it appears there are two physically different cables, presumably for the two different displays.

One has a noticeable flat cable of the flexible printed circuit type, plus other connections, that looks like the display end of my computer's cable. P/n 91P6830 which is in the HMM, or perhaps 91P6861, see http://cgi.ebay.ca/IBM-THINKPAD-X41-12- ... afb51#shId.

The other cable 91P6927 appears to be only thicker but narrower connectors.

[keithsketchley]

Success, I replaced the LCD cable and inverter board with used parts from eBay so I now have a stable display backlight with annunciator lights.
I’m not sure which part was bad, holding the inverter board down with a piece of eraser near the cable end helped keep it working, but the board is flexible and my spacer moved the cable. (All annunciator lights on the inverter board were intermittent then stopped working, display backlighting was intermittent with lid movement and getting worse, LCD itself seemed stable. The area of the cable where I’d expect deterioration from flexing is sleeved so condition is unknown, outside of that area I see the discolouration others have mentioned including near the inverter connecter.)

My x41 had the Samsung LTN121XA-L01 display (PN 92P6755/FRU 92P6754) which uses cable FRU 91P6830 (notable for all connectors being low profile and its bright brown colouring) and inverter FRU27K9993 (Ambit T621228.01). I replaced them with the same part numbers purchased used from Laptop Aid via eBay.

So, tips for doing the work.
First, preparation.
- become dainty, as the screws in the display area are small {well, one technique for us large-fingered old persons is to orient the computer so the screw being installed is vertical so may stay in place while you get the screwdriver into it}
- a Phillips #000 screwdriver of precision manufacture. I made do with a very good #00 but it was marginal if a screw was tight. (Most screws on the x41 can be handled by a #00, but display screws are smaller – in general x41 screws have a very shallow head which requires a precision screwdriver. The HMM lists a screwdriver and a screwdriver set but I cannot find them on Lenovo’s web site nor through Google. www.wihatools.com has both 00 & 000.)
- the usual thin knife to pry carefully.
- a tray to catch screws (else buy a spare screw pack
- double-sided tape such as the 3M stuff that looks like cellulose/Magic tape.
- a brush to remove paper dust and Twinkie crumbs while you are in there.
- the IBM HMM though it is not a lot of help, you have to figure most things out yourself, carefully.
- This is a good time to replace the keyboard if badly worn, as you need to get it out to replace the LCD cable.

The display bezel comes off with judicious prying after removing the screws at bottom corners. The top is a little tricky to get all the way up. There is some double-sided tape along the bottom but the bottom also snaps into place – important because the bezel holds the cable bend radius cylinder in place which is crucial, so you have to make sure that is all correctly in place. (The cylinder pivot journals are in the lid and the bezel holds the cylinder into them. A metal piece above it fits over tabs in the lid.)

Fit of parts:
Be careful with the antenna cables especially on left where there are both BT and WiFi, those route through hollows in the side of the hinges.
(I was able to avoid removing the circuitous WiFi antenna cables or the antennas by keeping the display in loose formation with the base, but had to unfasten the BT antenna.)
The BT antenna fits on posts in the cover and is taped to the cover.
The LCD cable connection is a slide-together connector but there is tape over it, presumably for extra security.
The LED keyboard light on the top left of the LCD cable is tricky to put back in place, it goes into slots hanging down from the top of the lid.
The inverter is tricky to get back in line with tabs in the lid, as it is bowed. At the right end there is a big tab with a hook on the end, the slot in the inverter board surrounds the hook.

For troubleshooting, note that the lid-closed switch is not involved except via system logic, as it is in base unit not display assembly (it is to the right of the inverter board location).

[keithsketchley]

More tips
(all my notes are for basic x41, tablet may well be different, certainly hinging is different and it is brighter)

Display front bezel
- pry with thin knife inward (i.e. away from sides of lid) on all four edges to get tabs clear of lid, and a bit toward you to keep them clear
- there is double-sided tape along the bottom between hinges

Lid (back of display)
After removing eight screws, push sides of lid back (pulling outward with fingers as needed) starting from bottom, then lift so the top clears the display (the latches in particular hang down).

I had to use double-sided tape to re-attach the Bluetooth antenna securely, and along the bottom just below the display area (thicker there). The tape I had was Scotch (3M) 667, probably not high temperature tape so I wouldn't use it on the display itself nor its circuit board (where there is brown tape holding the connector in place).

I had difficulty with getting the screw holding the ground circuit tab from the LCD cable to the inverter board, had to get a very small washer to ensure solid contact. Perhaps I lost a washer, perhaps the screw was cross-threaded, will find a #4 washer or maybe a stringing-retainer washer from an old Meccano set .

Beware that the assortment in screw packs may not be very good - the pack I bought from laptopaid had only one of the tiny screw used in the display (total 8 installed, six on sides of display and two at end of inverter). But we're going to do our work in a large tray to be sure we don't lose any, right?

Note that the LCD assembly in my x41 is a sandwich of LCD, backlight, and circuit brd.