Roland VM-3100 blank Screen

[pedronerd]

Hello guys, last night my father tried to use his VM-3100 but when he turned it on, only the backlight of the lcd turned on. The mixer is completely unresponsive. Do you guys have any experience with tis problem? Does anyone have the service manual? I can't find it on the web. Thanks

 

[JonSnell Electronic]

Check the power supply ensuring all rails are at the correct voltage.

 

[pedronerd]

The voltage seems to be correct. 0V:0V:5V:5V:-15V:0V:15V on the connector from the power supply to the main board.

 

[GeorgK]

Therer probably is a switching regulator for the 3.3V supply on the mainboard.
If you own a scope, check the function of the quartz oscillator(s), especially the one that is clocking the control CPU.