crwdns2936637:0crwdne2936637:0 crwdns2853008:0crwdne2853008:0 crwdns2918746:0crwdne2918746:0

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crwdns2933797:0Dave Empsoncrwdnd2933797:0crwdne2933797:0

crwdns2936043:0crwdne2936043:0 crwdns2933505:0crwdne2933505:0 Dave Empson

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-[* black] Check circuit board for any dry solder joints (re-flow solder with soldering iron if necessary). Maybe also clean switch with switch lubricant.
-[* black] If the circuit board looks fine, the final step is to heat-treat the board to heal any cracked solder. I used 160C for 5 mins in an old fan oven (best not to use an oven used for food). This temperature is below the melting point (217C) of lead free solder and probably heals a microcrack by crystal growth).
-[* black] The required time and temperature is by trial and error. I started at 5 mins at 120C and went up in 10C steps, testing after each step. The circuit board was suspended on balls of aluminium foil and was heated from ambient and oven cooled with door open.
+[* black] Check circuit board for any dry solder joints (re-flow solder with soldering iron if necessary). Maybe also clean switch with switch lubricant. Unfortunately this didn't fix my fault.
+[* black] My final repair attempt, was to heat up the circuit board in a fan oven to heal any invisible microcracks in the solder. I started at 5 mins at 120C and went up in 10C steps, testing after each step. After 160C, the keyboard was working much better, but after 170C it was dead!
+[* black] Hopefully your repair will be more successful.