If it's just a "handshake" issue, then powering down, and powering up the devices in different order will normally solve it, if the cables are good. So try it powering 'em up one way, if it doesn't work, try reversing the power up order. If that doesn't fix it, try a different device to see if a signal can be displayed. Still no signal after that, you might try a different cable. If those don't work, there may be an issue with the pj? Might want to check the output resolution/refresh rates are set to be compatible with the pj's requirements.