I tried using my 473nm DPSS once and it just wouldn't work. I swapped batteries, and later tested the voltages and they were in line. Still no output and I was afraid the laser was kaput. Then I remembered that those lasers don't like being cold, so I warmed up the laser near a fireplace for a little bit and it merrily started up again.
I doubt that'll fix it, but next time remember that DPSS lasers don't always want or need to be cold, just not overheated.