You left out one key piece of information Mattimus:
Was there a load (bulb) in place in that post lamp when you measured 75
If there wasn't a bulb there, then the 75 volt reading is probably
caused by leakage current around an almost completely open break in the
wiring from where the cell is to where you are measuring 75 volts.
If the bulb load wasn't there when you measured 75 volts, try putting it
in and measure again. If you get near zero with the bulb in, then you
will have to find where wiring break is and fix it.
If you still get 75 volts with the bulb in place you've got a resistive
joint somewhere in the circuit, it's probably in the order of 15 to 35
ohms. Check all splices carefully.
BTW, I've never heard of low voltage causing bulbs to shatter, and doubt
if anyone else has either.
Good luck, and when you find ourt what's causing the problem let us know,
Jeff Wisnia (W1BSV + Brass Rat '57 EE)
"If you can smile when things are going wrong, you've thought of someone
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