760 XD Keyboard

[paul-c]

Hi,
My Thinkpad 760XD keyboard has a problem in that some key's arn't registering.

Some of the keys developed a slight problem and were a little erratic when pressed, always the same keys.
The same keys have finally packed in and won't register at all and the machine will no longer get passed the bootup procedure with a message of 'Keyboard Error'

I was wandering if any keyboard from the 760 series would be compatible as a replacement ?

Regards..

[Unknown_K]

Other 760 series keyboards should work.

[paul-c]

Hi,
Yeah ! I reckon so myself to be honest, what difference can there be..

The 760 series all look the same, other than slight differences with internal specification..
Just though that there may be some Thinkpad guru on this site who would know for sure.

I can get my hands on one that came off the 760 EL for a price.
Guess I will have to take a chance and see.

Regards..

[ozzymud]

The keyboards are the same, except for the speakers... this quoted from someone on the net a while ago... dunno where, it was in my info text file...

My 760EL and 760XD have very different loudspeaker types. While the EL ones have an uncovered semitransparent black plastic diaphragm and open chassis holes, my XD ones have a shiny silver sheet aluminium grill with big round holes in front of a transparent diaphragm, and the chassis holes on the back are glued tight with a black felt ring.

When intact, both sorts sound astonishingly good regarding how tiny these yellcoins are. IMO their sound quality beats many 8cm speakers found in lousy clock radios. However in direct comparison both speaker types differ a lot. I noticed this when I exchanged the keyboard PCB assembly between both models first toghether with the speakers (after I instealled the ESS sound card in my XD).

The 760EL speakers sound a little dull and hollow, and in many games (e.g. on MAME arcade emulator) they were too quiet to hear them well. Installed in the XD they kept the same characteristics.

The 760XD speakers play at least twice as loud and sound quite bright and much more powerful. Unfortunately my right speaker was damaged and thus made a bright crackling distortion also in bass sounds, which was very disturbing. I expect that the voice coil rattled against the magnet gap beause either something was bent or melted or windings came loose by thermical overload. Thus I took out the speaker, carefully peeled off the felt ring and pryed with a screwdriver to bend the sheet metal chassis and cover of the playing speaker until distortion nearly disappeared. (I collect music keyboards and succesfully fixed many sound toy speakers this way.) I also carefully pushed in the flexible foil diaphragm to bend the voice coil. I manged this way to strongly reduce the crackling, but could not eliminate it completely. However after I glued the felt ring back into place (with a glue stick), the distortion disappeared almost completely. Only at high volume there are sometimes small residues of crackling, but it distorts only barely more than the other. I also glued a layer of window insulation foam rubber on the magnet and the rechargable battery to prevent rumbling.

I know a bit about high-end hifi (e.g. I modified and regularly use a Grundig 6199 tube amplifier from 1963 and have built my own TML speaker boxes), and I think that also these tiny loudspeaker chassis in the 760XD were likely developed by very bright propellerheads, since they not only sound tremendously better, but also don't look at all like average other small speakers. The diaphragm is embossed of thin foil with an unusually curved pattern (similar like in modern headphones) that apparently was designed to re-shaped and distribute partial vibrations similarly like the star shaped structure in the patented Manger loudspeaker. Also the relatively thick felt on the rear chassis holes likely works similar like a Variovent (a Dynaudio patented, non-linear air duct for speaker cabinets that damps large amplitudes stronger), and also the different hole sizes in the aluminium front cover certainly do something important like a sonic lense to spread the sound wave or even partly reflect it back to the diaphragm to interact with partial vibrations.

Objectively these 0.5W yellcoins are certainly not considered hifi, but the conditions under that they work are really extreme; they are tiny, there is almost no chamber volume behind them, the magnet lies directly above the harddrive and the effectivity and amplitude is enormous in ratio to their diameter. And despite all this they don't distort too much and even make a little bass.

Thus when you replace in a 760 series Thinkpad the speakers or keyboard assembly that contains them, always watch out to get the right ones. The aluminium covered speakers sound better and especially much louder than the plain black ones. But I also recommend not to turn them unneccessarily loud, since their construction is so extreme that there is certainly a high risk of mechanical or thermical damage. (In sound toys with similar tiny speakers it happens often that the voice coil melts itself through the plastic diaphragm.)

as far as interchangability...

Code: Select all

IBM FRU Part Number 29H9395 compatible with the following Models:

ThinkPad 760C 9546 (10.4 HPA), ThinkPad 760C 9546 (10.4 TFT), ThinkPad 760C 9546 (12.1 TFT), ThinkPad 760CD 9546 (10.4 TFT), ThinkPad 760CD 9546 (12.1 TFT), ThinkPad 760E 9546, ThinkPad 760ED 9546, ThinkPad 760ED 9546 (12.1 TFT), ThinkPad 760EL 9547, ThinkPad 760ELD 9547, ThinkPad 760L 9547 (10.4 TFT), ThinkPad 760L 9547 (12.1 TFT), ThinkPad 760LD 9547 (10.4 TFT), ThinkPad 760LD 9547 (12.1 TFT), ThinkPad 760XD 9546, ThinkPad 765D 9546, ThinkPad 765L 9547