Looking for service Manual

[Lustikus]

Hi!

I´m looking for a service manual for Clarion DXZ728R. Or can someone help me:

There is a battery inside for keeping the settings. This battery is lacked. So i need a new one this is not the problem. But the radio was working since it went cold here. So one day i inserted the Display and without switching it on the background illumination went on. And i have no chance to switch the radio on. So i opened it and found the battery. After desoldering it the problem with the background light is gone but i can´t switch it on. The signal from the display from the power switch to the processor is ok (high and when pressed it goes to nearly 0V).
I have already tried to reset the settings with the reset-switch. When the display is inserted and i press the reset button the backgound light goes on (so i think the battery made a short circuit).
Can it be that the firmware is empty? Or do i have to insert the right battery to get it functional?

Many thanks and happy new year!