Hi Christopher, Many thanks for your suggestion. Unfortunately, the method described in the service manual to get into test mode is the one that I am trying with no success. I find this strange since I have used this method in the past to access test mode with no problem. Having found the comment below on another post I do wonder if firmware v3.0 is limiting access to unlocking the volume limiter. Thanks again for your suggestion and I shall keep my fingers crossed that someone else on the forum has found a workaround to achieve unlocking of the volume limiter. Kind Regards, Wayne "Service manual for the NWZ-E46x series of Network Walkmen. Note that in test mode, you cannot override the Sound Pressure check (for volume cap), it is built into the firmware, which is not included here."