I've just bought my 2nd 3000 and it has a much later serial number than my first. You can get into service mode in the usual way, but the menu is quite different. OTHERS takes you to G test & V. AUDIO takes you to various options, including MAXOUT. This in turn gives an option of ON/OFF. Changing the setting does increase the volume, but not to the level of my other unit. Another option is SPL (?sound pressure level?) but I can't find any sub-menus to change this. A little progress, but also a little disappointment! Anyone else help?!!
