Question question about laptop keyboards

[ZippyDan]

I have an old project that I never got around to doing.

I have an old Asus laptop that came with a non-backlit keyboard. Not long after I bought the laptop, I also bought another Asus-brand keyboard with the same form factor - both for the keyboard itself and for the ribbon connector - but it also has a backlight (my plan was to wire the backlight directly to the motherboard).

Both the laptop and the keyboard are from around the same era of computing. The laptop is an Asus K55N and the part number for the backlit keyboard is 04GNV33KUS04-3.

Now after 6 or 7 years of forgetting about this little project, I decided to take a stab at it while I had the laptop open for other reasons (replacing thermal paste).

When I plugged the new keyboard into the motherboard I had these symptoms:

1. Most keys didn't work at all.
2. Some keys "worked" but would produce the wrong character on screen. For example the space bar might send "p" to the screen and the up arrow might send a "q". Not sure if those were the exact keys, but it was similar to that.

So what I'm wondering now is:

1. Are the symptoms I'm seeing typically indicative of a bad keyboard, or are they simply the symptoms of an incompatible pin-out (on the motherboard vs. the keyboard cable)?
2. I know that there is no standard for laptop keyboard connectors, but if it's an incompatible pin-out, is it common for keyboards from the same era, from the same manufacturer, and with the same form factor and number of pins to vary so much?

 

[fire400]

Extract and reinstall. Update or downgrade BIOS. Else, order a new keyboard. Put the old one in and see if it works again.

Likely it's the keyboard / motherboard getting old. Sockets, once ribbons are comfortable with the metal burn-in, if they are released and rejoined with new parts, cause interference/contamination that the circuits are not familiar with, thus sandstorm episode of random activity.

Additionally, some laptop models with back-lit keys are not compatible with non-back-lit OEM parts.

Speaking of OEM, guess what, where you bought your keyboard, some re-sellers purchase in bulk, failed QA parts from recycling companies or 3rd party vendors, and guess what, you're going to get random results, even if you bought it premium from a "trusted source."

Plug another keyboard into the laptop to see and make sure it's not just a software glitch, either.

Google it on eBay, and the keyboard appears to be $30-$50, European version.
$10 for a generic one though. I don't suppose you'd lose sleep if you had to order a non-back lit one if you really didn't care for the back lit?

Try pure isopropyl alcohol on internal connector tips, to clean out debris?