I have a DAC-100 that I'm using to convert VHS into DVD. It was working fine, but now I can't change the red lights no matter how often I press SOURCE and A ENCOUDE buttons. This happened to me earlier this month and the problem resolved unexpectedly. Now it's happening again.

Reading a little bit on the net I understand that I might have to change the dip switches. But I can't find them. Are they inside, is it safe to open it up?

Could it be that other hardware I have in the room are sending radio signals that deactivate my DAC-100 somehow.

I tried switching it off for several minutes, but the problem is still there.

Sorry if this has been posted before, I'm a newbie.