Logitech Internet Pro Desktop Keyboard Repaired
Fault symptom: Some keys are not working.
I was typing a letter in Word and I found some keys were not working so with doubt of dust I have removed the cap of the key and looked inside for dust but everything was ok, no dust in key area.
After putting back the key cap again I have checked by typing each letter and to my surprise the row from Z to M was not working.
So I opened the keyboard for further inspection.
Checked PCB for burn out and dry solders but everything seems ok
Now it is time for further investigation hence I have start tracing the track by continuity testing. Everything is fine near the suspected area. While inspecting the trace location I found some traces going towards upper side Multimedia shortcut key area.
So I moved a head towards Multimedia short cut key and started testing continuity on traces; there I found the continuity is losing the signal on one location while inspecting through magnifying glass I have noticed the trace coating is damaged for reconfirm for the fault again I have checked with Multimeter and I found the culprit area .
Now the problem is this trace are not normal copper traces where you can just solder jumper wire directly.
This trace are Conductive Paint so how to repair this trace? It needs special conductive paint pen; few years back for this type of problem I have ordered the pen “ONLINE” but this type of pen is not having more shelf life and it got dried within 3 months. Do not buy if you are not having regular work like this.
You can get two new keyboards instead price of the conductive pen.
Here I have used one old trick which was used earlier for repairing calculators; yes using simple Pencil just rub the pencil lead on damaged trace paint and you have done with the patch.
After the patching work completed I have checked the keyboard for working and I felt glad to save one unit from scraping. It worked perfectly fine.
This article was prepared for you by Yogesh Panchal who works as a Computer Hardware Engineer in Mumbai India.
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Note: You can check his previous repair articles in the link below:
https://jestineyong.com/how-to-repair-12vdc-output-power-adapter/
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Parasuraman
May 20, 2017 at 4:36 pm
Using pencil, VOW, news to me! Good info! Many thanks!
Yogesh Panchal
May 25, 2017 at 8:18 pm
Sir,
I have fixed so many remote of the TV with this technique this all are real time practical tricks.
suraga Electronics
May 20, 2017 at 5:41 pm
Hi.Mr,Yogesh Panchal
Good Repair, Good Solution damaged key board path.
Yogesh Panchal
May 25, 2017 at 8:19 pm
suranga,
thanks for the comment.
Henrique Jorge Guimarães Ulbrich
May 20, 2017 at 11:10 pm
Very well, Yogesh Panchal. I have used this pencil solution many times during the repair of remote controls. It (almost) resolves the problem.
Yogesh Panchal
May 25, 2017 at 8:20 pm
Henrique,
Thanks for your feedback.
Robert Calk
May 20, 2017 at 11:33 pm
Good job, Yogesh. Thanks for the tip.
Yogesh Panchal
May 25, 2017 at 8:21 pm
Sir,
Thanks for your feedback.
Albert van Bemmelen
May 21, 2017 at 1:33 am
Silver glue or the conducting pen you mentioned Yogesh, probably can be easily re-activated after it completely dried out. Just add some acetone. I did the same when I repaired a special modern stereo audio potentiometer in an older repair on Jestine's repair blog. Even scratched away silver can be re-used this way.
I also have here a defect wireless 2.4 GHz keyboard from my sister that only blinks when a key is pressed. Sadly the small board inside the keyboard uses a plastic covered chip which can't be soldered or examined because of it. And the USB Wifi dongle probably only works with the now defect keyboard because of the 14 digits long number printed on it. Only the USB dongle is recognized by my laptop.
Yogesh Panchal
May 25, 2017 at 8:22 pm
Albert,
Thanks for your feedback.
Alphonsus Lim
May 21, 2017 at 7:24 am
Great work!
Sometimes life is just about simplicity.
The pencil is now mightier than the solder.
Yogesh Panchal
May 25, 2017 at 8:24 pm
Sir,
Thanks for the comment.
Raymond Dube
May 21, 2017 at 8:57 am
Question: Shouldn't you put a coat of something over the repair as the carbon from the pencil will eventually fall?
Yogesh Panchal
May 25, 2017 at 8:25 pm
Sir,
Indeed good idea but never tried.
thanks for your feedback.
Gerald Musy
May 21, 2017 at 10:53 am
Well done Yogesh. Thanks for sharing
Yogesh Panchal
May 25, 2017 at 8:41 pm
Sir,
Thanks for your comment.
romy de luna
May 24, 2017 at 10:47 pm
Great!!! Thanks for this info.
Yogesh Panchal
May 25, 2017 at 8:43 pm
Romy,
Thanks for your comment.
dicksy
May 25, 2017 at 2:56 pm
thanks for the pencil trick.its new for me
Yogesh Panchal
May 26, 2017 at 6:54 pm
Dicksy,
Your welcome!
Humberto
June 4, 2017 at 8:25 pm
Hi Yogesh, a good method which you used, in my country we use it a lot.
Yogesh Panchal
June 6, 2017 at 5:13 pm
Thanks for the comment Humberto