Just to be sure I understand, the bulb you knew was good doesn't work in the the "problem" head. Have you tried taking this bulb (that you knew was good at least until before you put it in the "problem" head) out and putting it back in the good head?

If you have done this and the "good" bulb now doesn't work, then I wonder if there's a short in the new "problem" head that's causing it to blow the bulbs.