JB,
I've had the same problem. I also replaced the igniter and I can make it go if I heat it up twice (run through the start-up cycle, then turn off and run it again).
Mine works fine with a 12v battery attached so I think maybe my AC power supply might either be failing, underpowered, or something in the wiring.
Troubleshooting Tip: If the wiring has some strands broken and creating the extra resistance, it might feel hotter in those spots when it is under load.
Also, you might also see whether the contacts in the power socket on the DC are clean. Sometimes a light sand and tinning with solder can help.