Broke this down to the last board-did not remove the control board (the one that is used for the control panel buttons and displays). Every connector seems very secure-including eprom chips, I see no cracks or damage. I suspect the previous owner must have done something to corrupt the memory, or the CPU's clock is either malfunctioning or fried. it still seems to be trying to correct itself. Repeated power-on and off brings up different scrambled characters on the LED number display and different LEDs on/off over control buttons, but still no characters on the LCD screen. Yamaha service got back to me to send it in (looks like California service center tele number) but I still am hoping there is a factory test routine I could run on this before I pay what will surely be a huge amount to have this repaired. Keith, if you have the service manual you could upload, I would be very grateful. Still not giving up, finding one of these DTXtreme modules has not been so easy and the newest ones are completely out of my price range.
