After much troubleshooting, I nailed down the culprits (yes plural). I'll post the results in case someone else has the same problem later. First, thanks for the suggestion E76. It led me to dig deeper into the electronics to uncover one of the culprits. Also, huge cudos to the folks at NuArc who were extremely helpful and didn't charge me a dime for the advice and a scanned PDF of the manual! Now that is real customer service.

Problem 1 - thanks to the folks at NuArc, they let me know that yes, the fuses really do have to be slo-blo or time delay fuses. I was using good old off-the-shelf RadioSh fuses (yes 250v, 20A but they were not slow blow). Found an online retailer of slo-blo fuses with the right specs and switched them out. After testing with the new fuse, it still blew (bummer).

Problem 2 - Pay attention to the location of the wires on the transformer block! If you are running this on household 125, you must change the wiring from the factory pre-set 110v to the 120v setting.

Once I changed the jumper/wiring to 120 and put in a new slo-blo, voila! there was beautiful UV light. I did test the wiring on the 120v setting with the normal (quick RadioSh) fuse and it did blow the fuse. So, both steps were necessary. It seems that when it is warming up it pulls slightly more than 20A for a bit (thus the need for slo-blo) and if it is wired in 110v instead of 120, it pulls more current as well.

Hopefully this helps someone in the future! Now off to make some cyanotypes and van dyke prints!!!