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Help needed to understanding why only the left-hand part of a remote control works.

Benny7440

Jan 14, 2016
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For decades I've used a strong degreaser and tap water for cleaning these devices & almost always with very good results. Now, the right-hand buttons were requiring to push them very hard so decided to open it and clean it in the usual way: a small brush with degreaser, tap water on the brush a few times, a little sprayer with water & then ~1 hr of direct sun light. I repeated this scheme 4 times in a row but no change.

I decided to look closer and found a thin film of dirt around the IC & used alcohol @70% with the brush & found a big improvement (visually) but no function improvement.

What else it might be? A broken line or may it need a solder touch-up? Thanks in advance for any help on this!
 

pharaon

Oct 28, 2014
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since the left-hand part is working then the remote is working
here's my suggestion and it will work like charm
little foil paper "aluminum" under the rubber button, stick it to the rubber button with little of super fast glue , and that will make it work fine for any stop responding button

and let me know about the results
 

Bluejets

Oct 5, 2014
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For decades I've used a strong degreaser and tap water for cleaning these devices & almost always with very good results. Now, the right-hand buttons were requiring to push them very hard so decided to open it and clean it in the usual way: a small brush with degreaser, tap water on the brush a few times, a little sprayer with water & then ~1 hr of direct sun light. I repeated this scheme 4 times in a row but no change.

You've scrubbed off the conductive coating.
 

Benny7440

Jan 14, 2016
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Thanks for replying, pharaon, Bluejets & Harald Kapp!

I've tried to use other working rubber buttons over most of the non working side and it didn't work; also, used some of the right hand side rubber buttons on the working side and it worked ok. So, I don't think any conducting surface on the rubber buttons has been washed away: there must be another reason on the board itself.
 

Benny7440

Jan 14, 2016
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Have found a broken line at the spot arrowed below. Tried to make a guick bridge with a piece of alluminum foil but it didn't work. Need to try it again with more care. Found something unusual at the chip itself, the two pins at the left hand side weren't soldered!
 

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Harald Kapp

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Tried to make a guick bridge with a piece of alluminum foil
Aluminum foil isn't a good conductor. Aluminum has an isolating surface of aluminum oxide which needs to be penetrated to achieve contact. Use a short strand of copper wire instead.
Found something unusual at the chip itself, the two pins at the left hand side weren't soldered!
Unusual yes, but probably unused since the remote worked before.
 

Benny7440

Jan 14, 2016
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Just to make me clear enough in relation to the missing part of the line mentioned above: I was referring to the dark (wide) line above the metallic lines running from left to right as seen in the perspective shown. As far as I could see after inspection with a magnifying glass that's the only spot where it appears to be a missing line (interruption).

Harald, did you sugest to use a few copper wires as a bridge over there?
 

Harald Kapp

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Harald, did you sugest to use a few copper wires as a bridge over there?
No I thought you meant one of the copper traces on th ePCB.
The dark wide traces I cannot identify, the photo is not crisp enough.
 

Benny7440

Jan 14, 2016
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If you zoom in you might see that at the left side of the red arrow there's a copper wire running from left to right that doesn't disappear under the rubber black line that's running from top to bottom. That's the only portion on the whole board that I can see is missing. Curiously, it is at the working side... Also, noticed that under some of the rubber lines it appears to be some jumpers that sugest it is a multilayer board (although not going to the other side at any spot).

Any idea at this point will be welcome! I'm out of any...
 
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