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I have a wireless keyboard with a defective on/off switch. The switch has a little play, and it's closing the circuit only when it is almost pushed to the extreme position for on. If 0 represents the leftmost position and 1 the rightmost one, it's closing the circuit for a number around 0.8.

So I decided to disassemble the keyboard and see whether it's possible to repair this. Here is a photo of the circuit:

sw5 enter image description here

The keyboard currently uses four 1.5V AA batteries, and I also intend to use an external power supply instead. So I would like to permantently close the circuit at SW5.

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Without a hot air gun suitable for SMD rework, I'd go at the switch with a Dremel, being careful not to pull the pads off the board, and then clean up each pad with an iron and braid. Then lay down whatever connections you'd like by running wire wrap wire

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It's not clear to me whether the switch is in series with the power supply or is just used to set an enable pin on a regulator. If the latter, you may be able to force the enable pin active and leave the switch on the board. Perhaps removing R46 or shorting one of its pads to ground (next to the "C29" label), depending on the circuit. It may be safer to use a 100-1k ohm resistor instead of a dead short.

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