The following steps have proven successful in restoring the ability to print from a Quadra 840AV to a Personal LaserWriter NTR:
1. Ensure Speech Recognition is turned off.
2. Ensure that Virtual Memory is turned off.
3. Check to see if the Printer is connected to the Quadra 840AV's printer port so that the built in LocalTalk connected can be used.
4. Reinstall the printing software for the Personal LaserWriter NTR.
5. Reset the PRAM of the Quadra 840AV (RAM parameter settings). Hold down the Command, option, P and R keys while starting up the Quadra. The Quadra will start up normally but after several seconds will restart once again.