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I had an air con remote control that wasn't working at all. But at some point I noticed that when I turn on the air con manually and the room gets cooler, the remote control works as expected. I thought it can be caused by moisture inside the device and probably something happens with it when it is cold. I tried different batteries and it didn't change anything - the remote was operational only when it was cooler than 29 C (I live in a humid tropical country). I ended up keeping the remote in the fridge without understanding the real reason of the issue.

Now several years passed and my Xiaomi Mi Band 2 stopped working. After a lot of searching I found out that many people had the same problem and putting the device in the fridge fixes it. I tried it and amazingly, it worked!

What can be a reason of this behavior? Temperature, humidity or batteries?

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  • \$\begingroup\$ There appears to be plenty of stuff on the internet about putting your Xiaomi Mi Band 2 in the fridge so maybe you can conclude something from one of those links? \$\endgroup\$ – Andy aka Dec 5 '16 at 13:00
  • \$\begingroup\$ Measure the batteries. Open the remote control and check for cracks. Resolder all joints in it while there. \$\endgroup\$ – winny Dec 5 '16 at 13:18
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Could be thermal expansion causing a poor connection to fail. When the unit is cooled, thermal contraction makes the dodgy connection.

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  • \$\begingroup\$ That sounds like a good reason. I'm a newbie here, should I mark this as a correct answer though I'm not sure? \$\endgroup\$ – ajayver Dec 9 '16 at 10:59
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Design flaws leading to components getting too hot and thus working in critical condition could as well be a valid reason as I see it.

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  • \$\begingroup\$ A remote control getting too hot working on batteries and even if not used for several hours? \$\endgroup\$ – Uwe Dec 5 '16 at 18:31
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If many other people had the same problem, it is possible that there is a common design flaw. Did you repeat the test with the fridge several times? What happens after some hours after you took the remote control out of the fridge, it works for some hours and then fails again repeatedly? The possible design flaw was not detected in pre production tests because all tests were done at temperatures well below 29 °C. I would suspect a design flaw inside one of the chips used in the circuit. It is unlikely that any passive component is causing this problem.

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  • \$\begingroup\$ The remote control stops working after around 10 minutes outside the fridge. \$\endgroup\$ – ajayver Dec 9 '16 at 10:56
  • \$\begingroup\$ Though I have two exactly same Mi Bands bought on the same day, one works perfectly fine, another one stopped working after one week and now works only when cooled down :) \$\endgroup\$ – ajayver Dec 9 '16 at 10:58

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