SOLVED: Keyboard Problem: Erratic Fn Key on Notebook

[CobraPilot]

SOLVED (See update) Keyboard Problem: Erratic Fn Key on Notebook

Compaq Presario 2500 DP663AV
Win XP SP3

I began having keyboard problems as if the Fn key (which activates the various alternate uses of keys which have blue markings in addition to the white-on-black ones) was sticking . . . sort of . . . . sometimes . . .

o At bootup, can't directly access Setup (F2) because its blue function of Screen Brightness+ is activated immediately. (Same for F1, Help/Screen Brightness-.)

o At bootup, can't directly access Safe Mode because F8 is Fn's NumLock and is activated immediately.

o Can access Safe Mode and Setup by alternate means, but there seems to be no BIOS setting that might involve toggling the Fn Key. In fact, no mention of Fn Key at all.

o Letter keys with blue numbers (for Fn use as a keypad) do not work at all, with or without Fn press.

o Letter keys with blue symbols enter those symbols when pressed, regardless of whether the Fn key is used.

o Keys with blue functions (such as backspace-mute, page up/down-volume up/down) access only the blue function; e.g., backspace doesn't work at all on a text document.

o "S/s" key does not work (no blue option) when pressed directly. It WILL enter "S/s" if pressed quickly after "a" or "d" is pressed; i.e., "as" = "as"; "ds" = "ds" onscreen (and capitals).

o "?-/" key press = "/" only, even if Shift key is pressed.

o Pressing >/. key (no blue function) = delete subsequent text after the cursor.

o Control Panel > System troubleshooting shows the keyboard working properly.

o Uninstalling/reinstalling keyboard has no effect.

o An external keyboard works perfectly with this notebook, so that's a workaround (if I also get a USB mouse), but defeats the purpose of having a notebook.

At first, I thought it was just a sticking Fn key, but that doesn't seem to explain the situations above where a key has no Fn (blue) option, yet doesn't work or doesn't work as expected.

Extensive online searches also seem to assume the only problem is a stuck Fn key, but do not allow for the inconsistencies I've described. Compaq online support hasn't been helpful, either.

A few times, this problem seemed to go away, sometimes after a reboot, sometimes otherwise with no noticeable common factor. The notebook's internal fan works well, and is operated atop a dual-fan cooler for add'l cooling.

I have not yet disassembled the notebook for further examination.

Any ideas?

[Cornucopia]

If it's like one I had, the MOBO is cracked, and slight weight put on it (during typing or even when NOT typing, if you leave the weight of your hand on the chassis) can cause it to do a number of different things.

If using an external USB keyboard isn't an option (because of weird things still occuring), it sounds like it's time to get a new laptop...

Scott

[Nelson37]

Sounds like keyboards I have seen that had something spilled on them. These are usually less than $50.00 to purchase, removal and replacement varies as to the degree of PITA it is.

Be exceptionally careful with the mylar ribbon connector and ESPECIALLY the plastic locking clamp. These tend to get brittle with age.

[CobraPilot]

If using an external USB keyboard isn't an option (because of weird things still occuring), it sounds like it's time to get a new laptop...
Scott

As mentioned, an external keyboard works perfectly.

Sounds like keyboards I have seen that had something spilled on them. These are usually less than $50.00 to purchase, removal and replacement varies as to the degree of PITA it is.

Nothing spilled on it since I've had it (3+ years, hand-me-down from family member who upgraded).

Wouldn't be opposed to keyboard replacement attempt (been a tinkerer for years), but I'd love to know what might be causing this if a keyboard spill isn't the culprit. Controller, ribbon cable, loose cable, etc. before I start with the screwdriver and expense of new keyboard that might not solve problem. "Buy a new laptop" isn't a solution, in this case since this one has been a backup unit since I've had it, but actually the fastest computer I have among several. Not ready to junk it without a fight.

[Nelson37]

Other than spillage, which often happens with the owner unaware, about the only other cause would be a bad keyboard, or faulty individual key switch. Possilby a loose or torn ribbon cable but highly unlikely, and you would have to do the disassembly to find out. Some KB are as cheap as $30.00.

On the spillage - I have taken apart several where the owner swore up and down nothing had spilled on it, but the evidence is clearly visible.

The next step is replace the keyboard. There is nothing else cost-effective that can be done. The cable is integrated into the keyboard unit.

You could pop off some of the switch covers and check for foreign objects, the problem there is that laptop KB switch covers often do not survive disassembly, especially if they are older and the plastic has become brittle.

Replace the KB or live with it as it is.

[CobraPilot]

Excellent overview and suggestions, Nelson 37.

Do you have a recommendation as to where to find a replacement keyboard?

[Nelson37]

Not really, I don't order them often enough to have a regular guy. I just google for the model and replacement keyboard, then check several and choose the one that has the least "Schlockenheimer" look to the page. I use a limited card for net purchases.

Was re-reading your list of symptoms, and it just might be a stuck key. A stuck function key, in particular, could cause some odd problems, and not out of the realm of possibility that could be it. If you're gonna chuck the KB anyway, it's worth a shot.

GENTLY pry off the FN key cover, rock it and you'll get a feel for where the "latch" is, it's a pressure fit. Watch carefully for what looks like a small staple, that will be the "hinge". Don't lose it, or let it fall under the other keys. The actual keyswitch is a very small button with very limited travel, but see if you can free it up - toothpick or paper clip or other small tool.
Power off and then back on.

See if that changes the behavior, either all or in part. Test first, don't touch that switch until after. It may be usable without the cover, you may have to pry it up each time.

I'm more curious then anything else at this point. Have you blown out and vacuumed and used a clean paintbrush to clean out the keyboard? A small object lodged in there is another possibility. Suck, blow, and brush several times. Also look carefully, tilt it around while off and listen very carefully.

[CobraPilot]

Thanks for the continued clear, concise advice!

I'm more curious then anything else at this point. Have you blown out and vacuumed and used a clean paintbrush to clean out the keyboard? A small object lodged in there is another possibility. Suck, blow, and brush several times. Also look carefully, tilt it around while off and listen very carefully.

With the notebook off, I've held it at different angles (including upside down) and "exercised" all the keys to try to rid the keyboard of any "dandruff" or other debris. I will escalate this a bit with add'l vacuuming and brush work to see what happens, using your suggested techniques.

[redwudz]

I replaced a KB on my Asus laptop a few months ago. At least with Asus, it's a very simple process to replace the KB. Just pop it out, disconnect the ribbon, plug the new ribbon in, pop the keyboard in. It took five minutes.

I first did a internet search for information for replacing my KB. There were several sites out there, videos and tutorial. Then I did a second internet search for a keyboard. I found several on E-Bay. The one I finally went for was $16US. It was shipped from China. I went cheap as I didn't really know if that was the problem. But it worked perfectly.

If the KB had been $50 or more, or very difficult to replace, I would have tossed the laptop as I had it for two years and only paid ~$400 refurbished.

So, do your research.

[CobraPilot]

redwudz says: So, do your research.

That's why my second stop was here!

My first stop was to d/l the maintenance manual for this model which seems to suggest replacing the keyboard wouldn't be too hard to do, if all else fails.

Thanks!

[CobraPilot]

SOLVED: Replacing keyboard solved the problem, which is probably no big surprise.

Found exceptional value replacement (said "refurb" but indistinguishable from brand new, identical OEM) for $9.95 plus postage. Total outlay, less than $15.00.

Found supplier on eBay, ZKarlo, Inc. Order included full instructions online. Package arrived a full 3 days before "expected arrival date." 100% satisfied.

Physical replacement steps were about as simple as could be, taking about 15 minutes.

Examining the original keyboard, I couldn't find any obvious flaws or breakages. Tapping it above a dark surface produced a few flakes of keyboard "dandruff," but none that produced an "A-HA!" moment.

Thanks for those who offered suggestions and insights. Those, plus my "solved" feedback, are all part of the VideoHELP role of this exceptional board!

[enim]

Erratic Fn Key

Nothing to do in much detail with your post as it is already SOLVED.

Whenever you have multiple choices from F1 to F12 FuN keys, just drop or ignore the erratic one.

[CobraPilot]

Erratic Fn Key Nothing to do in much detail with your post as it is already SOLVED.
Whenever you have multiple choices from F1 to F12 FuN keys, just drop or ignore the erratic one.

You've lost me with these comments.

As I mentioned, replacing the keyboard solved the problem. The PC was unusable before, as described in the various "symptoms."

[jimdagys]

In China, where internet cafes are everywhere, daily, the keyboards are turned over and wacked hard to remove the detritus that falls into the keyboard.

[Cornucopia]

For instances where there is the likelihood of things spilling/crumbling/accumulating on/under the keys, the simple & cheap thing to try is one of those clear vinyl key covers! $20-30 USD, not a bad preventative investment. I've seen those in use at auto repair shops or in the field, and they've kept the underlying keyboard in near perfect working order for maybe a decade or more (probably more likely a key switch would break due to age).

Scott

[CobraPilot]

Didn't think of one of those for laptop/notebook keyboards . . . . .

Of course, in this case, spending less than $15 to replace a bad notebook keyboard was very cost-effective, no worry about proper fit, interference with closing the screen/cover, etc.

Live and learn!