If you have already tried adjusting the colour temp in the user service menu (press and hold the menu/exit button while the menu is displayed) then I suggest you send the monitor in for investigation.
Also check that the "preset" option is not turned on as this will disable the controls on the front control panel. If it is on then you will not be able to adjust the colours using the knobs.
Page 27 to 29 of the operators manual explains the menus.
Just to confirm John Sandham's post, Imotek can repair the Sony CRT monitors.
If you send the monitor to us we would firstly assess the fault and then provide an estimate. We would not carry out any work until we had been authorised to do so by yourselves.
Just to warn you though....Sony have stopped making/supplying a lot of parts for CRT monitors therefore we may not be able to obtain certain parts should they be required.
Contact:
Service Dept, Imotek International Ltd, West Newlands Industrial Estate, Somersham, Cambridgeshire. PE28 3FF
Tel: 01487 843193
Fax: 01487 843030
Email: service@imotek.com