Blowing Cyber F1 fuse every-other week

I replaced the logic board, the l/b to psb harness about 2 months ago. About 3 weeks ago I started blowing F1 fuses. It'll run for about 2 weeks then blow.
Then today when I replaced it, the fixture still didn't show power, even though I know it has power coming to it. Reasons why I'm blowing them, and why it wouldn't show power after replacing it today when it would the other times (other than I have a show tonight-- Murphy's Law?)??
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