Fun with keyboard guts

Avder · Post by **Avder** » Wed Jun 02, 2004 1:26 am

Well this should amuse you guys...

Earlier today my desktops keyboard wenton the fritz. Pressing one key would make it think 3 were pressed, some keys didnt work at all, etc. The first thing I did was try to reset the keyboard by pressing ctrl-alt-del and esc and whaever a bunch of times with a notepad window open. Nothing worked. I shut down all the computers that are connected to it (3 of them through a 4port kvm switch). Didnt work. Eventually I deduced that water had somehow gotten inside of it. I spent the next 60 minutes or so dismantling the board by removing all keys, all the screws on the back, and then the screws that were hidden beneath the keys.

Sure enough, there was water inside the keyboard.

I put the mylar sheets next to a fan and spent the next 5 minutes giving the upper part of the shell a good washing out, as all sorts of particles had built up under the keys themselves.

Eventually, they mylar sheets dried out and the keyboard should start working again like normal right? Well, not exactly...

For whatever reason, part of the board doesnt work at all. Keys B-. for example dont work, neither did either ctrl key, or the down arrow.

Eventually I was able to log on to my windows installed by using some paper clips to jumper some contacts on the keyboards PCB to fool it into thinking ctrl-alt-del is working (hooray for keyboard matrices posted to the internet) Why cant I just press keys to do this? Anyone know of a really cheap way to clean contacts so I dont have to buy a new keyboard?

Yes, I'm that friggin broke that I cant even afford a replacement keyboard.

AceCombat · Post by **AceCombat** » Wed Jun 02, 2004 7:37 am

did you wash with a mild soap and water between each of the mylar sheets? chances are there is something still shorting out those keys and its lodged between the mylar sheets.

also check were the little PCB Board makes contact with the kb cable. make sure they are contacting the proper circuits and wires

Mobius · Post by **Mobius** » Wed Jun 02, 2004 2:53 pm

soapy water - fantastic idea - leave a nice layer of insulating soap on the films. Good one.

No. Use IPA (Isopropyl Alcohol) to clean the silver terminals on the bottom mylar sheet. Also, the reason for a failing key(s) can be that the circuit-making mechanism can be badly "set". Some KBs use silicon rubber "cones" to close the circuit - and these must be correctly alinged for them to work.

AceCombat · Post by **AceCombat** » Wed Jun 02, 2004 4:32 pm

okay since mobius wants to be a smartass, mild soap as in Dawn dish soap is what i meant by "mild soap"

Lothar · Post by **Lothar** » Wed Jun 02, 2004 4:41 pm

go to the thrift store and buy a $2 keyboard. It's cheaper than the rubbing alcohol or soap you'll use trying to clean the current one, and it'll take less time.

Or, go to the computer store and buy a new keytronic keyboard for $20.

Avder · Post by **Avder** » Wed Jun 02, 2004 6:31 pm

I already replaced the keyboard. However, as an entertaining project, I would like to repair this one to 100% working condition. Please dont suggest "get a new one" suggest repair options and opinions

De Rigueur · Post by **De Rigueur** » Wed Jun 02, 2004 6:39 pm

AceCombat wrote:okay since mobius wants to be a smartass, mild soap as in Dawn dish soap is what i meant by "mild soap"

Maybe Mobius hasn't seen the commercials showing that Dawn rinses clear.

AceCombat · Post by **AceCombat** » Wed Jun 02, 2004 9:14 pm

De Rigueur wrote:
AceCombat wrote:okay since mobius wants to be a smartass, mild soap as in Dawn dish soap is what i meant by "mild soap"
Maybe Mobius hasn't seen the commercials showing that Dawn rinses clear.

i figured it was something along those lines

Avder · Post by **Avder** » Mon Jun 07, 2004 1:24 am

I FIXED IT!!!!!

I'm typing on it right now.

It wasnt the contacts at all. What happened was the printed wires on the mylar that connect the contacts ot the small pcb were corroded right at the point where most of the water was. To fix it, I took advantage of the fact that the two wires that were corroded were the ones closest to the bottom of the mylar sheet and cut pieces off and did a sorta long-winded bypass with aluminum foil that I had laying around and some electrical tape. The combined thickness of the foil and electrical tape wasnt enough to disrupt the contacts of the lowermost keys. I feel proud

Hooray for jury-rigging a keyboard!!

Now I can take this cheap replacement back and get my money back.