no sound control after reassembling

Hey,

i changed the display assembly of my iphone 4. Therefor i used your step by step instructions. But i forgot to activate the sleepbotton. I recognized it during the repairation and activated the sleepbotten then.

But after finishing the repairation the more-loudness control button is not working. When i push and hold the plus-button it even minimizes the loundness. But i can still change the loundness by displaymovements, while i´m listening to music.

I hope the there´s a solution for my problem and you can help me.