my,beats,studio,0500,won't,enter,in,to,pairing,mode

I inherited a pair of Beats Studio wireless headphones from a deceased uncle and I cannot get them to go into pairing mode. I understand that when you hold the power button down for about 4 seconds, or until the fuel gauge lights up, the main power LED should blink, indicating the headphones are searching for a device. Mine do not go into pairing mode. Can anyone help?