keyboard stops working after/during boot

[Braue]

Hi, I am having no end of dramas withmy keyboard and would appreciate any suggestions. To wit:

When I start the PC, normal "press del for setup" msg comes on. POST finishes and PC starts beeping quickly - same noise it makes when you hold down a key and the kb buffer fills up. It then searches for drives etc as usual, boots up but I cannot type anything at all (including no password at the login screen). Needless to say, this is difficult for me particularly since i write for a living.

Every once in a while (ie every few hard resets) the kb is recognised long enough for me to type password, boot win xp, and maybe write an email but at some point the kb stops working. all apps still run ok, for ex i am writing this using mouse and onscreen keyboard. Also, all apps act as though CTRL key is being held down ie shutdown screen says standby not hibernate, ms outlook asks whether i want to start in safe mode etc.

As my kb was 7 years old i first thought it had worn out but new MS keyboard behaves the same annoying way. this leads me to believe the prob lies in the motherboard's keyboard connector somewhere, probably not a winxp issue since it happens during POST and well before win is in the picture.

Any suggestions of solution, or hair transplant specialists, most welcome. Thanks in advance David

 

[bcastner]

Unplug the keyboard and turn in upside down. Holding it by its ends, slam it rather firmly five timees on your lap.

Try it again.

If this does not work turn the keyboard upside down again, and remove the screws. Split the keyboard case, and lift the keyboard circuit board slightly to see if the keyboard cable is firmly plugged into the little socket on the circuit board.

If it is, blow comprssed air around the keyboard keys. On most keyboards you can remove the caps themselves without too much difficulty, although leave the space bar connected. Clean up the junk found there.

Test each keyswitch to make sure it feel suitably springy. Replace the keycaps. Scew it back together. Try again.

If it still does not work replace the keyboard. Note the size and shape of the connector at the end of the cable that goes into the computer. You may need an adapte if it is not the small PS/2 style when you replace the keyboard.

Note: if the problem is the keyboard connector, then remember that you can purchase keyboards that use USB connectors that may make sense for you if you have USB ports. I view it as unlikely the keyboard connector is at fault. It is more likely junk stuck on the keyboard switches, or a failing keyboard controller IC on the keyboard itself.

 

[Braue]

Thanks for the suggestion. I tried slamming the keyboard quite furiously in every possible orientation, and was tempted to even throw it out the window, but no luck. The effect I've described happens even with the brand-new, out of the box keyboard I bought yesterday thinking that the original keyboard was at fault.

At this point, the keyboard is still dying on me at random intervals. Left alone for a while (ie half an hour or greater) it seems to come back to life but quickly stops working again after about the equivalent of one email. I have been reduced to using a wireless connection and Remote Desktop to access my desktop system from my notebook. Clumsy but at least I can get work done.

Since the behaviour is happening regardless of whether I'm using the old or new keyboard, does this narrow it down to the keyboard connector? I don't think it's a Windows/driver problem since it happens right during the POST. I dread the thought of having to buy a new motherboard, CPU and memory just because of a stupid problem like this.

 

[bcastner]

The keyboard is a funny thing on these systems. The interrupt for the keyboard is rarely masked by software, so it has a relatively privileged existence among all of your devices. It is also directly tied to a completely unmaskable interrupt used to reset the system, and tied as well to addressing more than 1 megabyte of ram.

So that leads to some curious things to look at for keybaord problems:

If you have a hardware reset switch, examine it closely (power off). These have a tendency to wear out, or loose their springiness. Make certain the switch travel feels normal and its return position is full.

Try taking out your RAM chips and reseating them. Blow out any crap in there while you are at it.

If after this you have no joy, go into the BIOS and if the feature exists to disable a stop on error, disable it. Then go buy a USB keyboard.

 

[Braue]

Thanks, that confirms my suspicion that USB is the way to go. The keyboard I bought works off of USB, but Microsoft was nice enough to neglect to include a PS2 to USB adapter that would let me use it with USB. Looks like it's off to the computer fair.

 

[bcastner]

My personal experience with the USB-2-PS2 adapter is only with mice, and it is not a good one.

If you do not have any USB ports a two-port PCI board should run about $12-13 bucks. A 4-port about $32-35.

The 2-port you can usually bargain for, as most opt for the 4 port.

 

[Braue]

Turns out it was the PS/2 port that was bad. I returned the new PS/2 keyboard (which didn't work) and bought a USB keyboard, which is working beautifully. I've never had a PS/2 port fail on me before -- how strange.