A small problem with my '73 MGB. Someone before me has installed a
not-exactly-new Pioneer (one of those SuperTunerIIIs with the cassette)
and a couple of 100W 6x9s 3-ways behind the seat (luckily, they were smart
enough to buy the self-contained version (maybe made for trucks?) of those
speakers and so didn't have to cut anything to install them, they just sat
them in the back.)
Well, the relatively-simple setup sounds great, but my hypothesis is that
maybe it was wired incorrectly when installed or that it is simply too
much load for the current wiring setup. I'll explain: it seems
that the circuit for 'constant-power' is either shorted out or way
overloaded. All the things that should run regardless of ignition
position don't work, such as: the highbeam flasher (high-lo still works,
just the flasher doesn't), the dashboard "courtesy light" (over the
radio), the seatbelt/door buzzer (probably a blessing), the horns, the
cigarette lighter, and the radio's own internal 'contant power' circuit
also seems to be either unhooked or not in this circuit as it looses its
memory presets every time the car is switched off long enough to empty its
capacitors.
I tracked the problem to a blown fuse in the box under the hood. I
replaced the fuse with a new one...it promptly blew out. I switched off
the ignition and removed the key and repeated both steps (add new fuse,
watch as fuse frys instantly.) Both fuses were 20A...I was afraid of
sticking larger in there for fear of damaging wiring.
My question, I guess, is if anyone has any insights on this. Should I go
with a much larger fuse? (30A? bigger still?) Does this sound like a
problem that the addition of a mere radio would cause? Suggestions?
neil doane
Terre Haute, IN
USA
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