Most likely: weak batteries on/off switch has internal corrosion Battery contacts corroded If fresh batteries do not cure the problem, it needs repair. Consider the cost of repair vs. replace with another Maxxum 5000/7000 on Ebay. They go pretty cheap these days. They're practically giving away the flashes for those early maxxums, even the 4000 flash.
Answers & Comments
Most likely:
weak batteries
on/off switch has internal corrosion
Battery contacts corroded
If fresh batteries do not cure the problem, it needs repair.
Consider the cost of repair vs. replace with another Maxxum 5000/7000 on Ebay. They go pretty cheap these days. They're practically giving away the flashes for those early maxxums, even the 4000 flash.
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