Had the issue where the UP button would only raise the desk 1/4″ and a time, DOWN button worked fine. Researched tons of blogs (with no luck on the work-arounds). Called IKEA, told them the issue…they know it’s been a problem. The they replaced:

AS-P-9287067 510 138684 SWITCH UP & DOWN INCL-KEY 1
AS-P-9287067 510 138685 KEY FOR UP & DOWN SWITCH BEKAN 1
AS-P-9287067 510 138688 TRANSF.WITH CABLE 34V 2,2Amp 1
AS-P-9287067 510 138689 EXTENSION CABLE FOR TRANSF. 1
AS-P-9287067 510 138690 CORDSET XXX 3000 NA C7 BLACK 1

No questions asked. 5 year’s old. No proof of purchase. Very satisfied how they handled it.