> My red light came on! I know, I know, it's either the battery, the
> generator, or the control box, or the wiring in between - nothing else in
> that circuit. Unfortunately, I do not have a voltmeter, so I can't check
> the generator - but here are the symptoms - I'm leaning towards
> the control
> box, but maybe not: Ever since I got the "2" restarted, the ammeter has
> always registered 30++ (its pegged to the plus side) - I always
> thought it
> was charging the battery, as I was doing a lot of odd electrical repairs
> with the car on and not running. However, after my 30 mile drive, it was
> still pegged on the plus side - the battery should've been
> charged. By the
> way, the ammeter does move, it is lower when the engine is
> running slower,
> or at idle, and does register a minus, when the car is not
> running and the
> lights (or wipers) are on. The red light came on on a restart, and there
> was nothing different before I turned it off.
David, I hate to say this ... but my guess is that you now have a bad
generator, in addition to whatever problem was causing it to charge at full
tilt.
Generators are psychotic devices, they have to be restrained to keep them
from destroying themselves. It doesn't take very long, putting out more
than the rated 19 (or 22) amps, before the windings overheat, ruining the
insulation and throwing solder from the commutator. Even 22 amps is of
course less than full scale on the ammeter, so you should _never_ see the
ammeter peg on the + side.
The previous problem may have been a wiring short, or a problem inside the
control box. You'll need to resolve it after you replace the generator, or
the new one will burn up in short order too ...
A word on voltmeters : the workshop manual mentions using only a "moving
coil" voltmeter. At the time, "moving coil" was synonymous with
'sensitive', ie a voltmeter that draws very little current from the circuit
under test. However, today's digital voltmeters are far more sensitive than
even the moving coil voltmeters, and so are entirely adequate for 99% of
automotive purposes. Their only limitation comes when trying to read an
average of a varying voltage, like the field voltage for a generator or the
output from a "voltage stabilizer" as used on the later cars. DVMs take a
'snapshot' of the voltage (which it may take them many seconds to display);
then take another snapshot, display it, etc. When looking at a varying
voltage (like a generator field), the reading appears to jump around.
However, the exact average is usually not important anyway, so this really
isn't a significant limitation. They have the big advantage of being far
more rugged than moving coil voltmeters, enough so that I carry one in the
trunk. (My last sensitive moving coil voltmeter didn't last a month in the
trunk of my TR3; my current DVM has been there some 10 years and still
works.)
And, with DVMs available so cheap today, I can't imagine owning a LBC
without one. I've already thrown away my most recent HF (Harbor Freight,
purveyor of fine Chinese junk <g>) flyer, but ISTR there was a DVM in there
for $4 ...
http://www.harborfreight.com
Randall
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