x340 problem

[shomyx]

Please need help.
I have problem with this multifunction. When I power on he start initialization on display is message "performing self test" and "worming up" and after few minutes display is blank and cant do anything with functions tasters on user panel. I try to change toner chip(chip is almost off over),power on, start initialization, on display is "performing self test" after few minutes scanner is moving then I have sound signal and display message is "88 toner low", confirm with confirming taster but again I haw problem with functions tasters on user panel- no response except rejecting sound. Any solution is helpful.