Do I need a new keyboard or motherboard...

[Kaieye]

I have an Inspiron 4000 notebook that works fine for about 10-15minutes until it heats up. After that when I press the S key, I get SF. Press S one more time quickly and fast and SF shows up. Do you think that the keyboard is busted or the keyboard controller on the mb is flaky?? After a while the f key is displayed like ffffffffffffffffffffffff... until I press the enter key.

Any ideas about how to tackle this problem??

 

[Bitdog]

Virus scan ?

Can you attach an external keyboard & test it ?

My 104 external key boards always get full of debris
inbetween the thin clear plastic sheets (with conductor)
so I clean the contacts with alcohol.

Do you have access to an air compressor/ air knozle to blow it out?
Some times internals get clogged with fuz & a real air hose cleans stuff up real good.
Open it up & blow everything out, use an old tooth brush to clean any fans, blow it out, etc.
I once made a air blower out of one of those 12 volt emergency tire inflators.

Does it show the CPU heat via software ?
Maybe the keyboard screwing up is a hint of worse things to come, like CPU overheat?

 

[TRUMPHENT]

I presume the notebook is out of warranty, correct? My guess is that the mainboard and keyboard controller are fine. Keyboards have more to go wrong with them. The membrane switches and circuits are fragile. I would try cleaning it, disassembling it for inspection, etc. Having said that, I would also have the replacement keyboard waiting and ready to go in. I have never successfully reassembled a keyboard and have it work like factory new.
Something on the mainboard may be producing excessive heat beneath those keys .

 

[Kaieye]

Thanks for writing. I am going to take the cpu hs off to double check for possible overheating and to double check the ps/2 external ports and try to blow some air around it. My hunch was that it was the keyboard problem and I do have a new keyboard coming in.

Thanks for writing and I'll let you know what happens...