You need to replace the main 60 amp breaker. This is a thermal type
breaker and as it gets older the contacts build up oxidation and self
heat more reducing the breaker rating.
You are lucky!! When my 60 amp breaker popped one night the load
dump fried the alternator field, the voltage regulator and the over
voltage lamp.
I measured the 60A breaker and it would pop at 35 amps.
Cessna wants lots of money for the 60 amp breaker but it still is lots
cheaper than a new alternator and regulator.
On a C172M the 5 amp field breaker will NOT protect the alternator
field winding since it is not in series with the alternator field. It
protects the over voltage relay that draws only 0.1 amps.

On Mon, 03 Nov 2003 21:08:22 GMT, "Mike Z."
wrote:

Ok, here is one for you.

The other night, about the time I landed, I hear a pop and remember seeing a visible flash. I see the amp gauge has a big discharge.

After I taxied off, I try resetting the alt half of the master. The high volt light is dimly lit and glows brighter when I turn off
half the master but that doesn't fix anything. I find that a breaker is popped, so I reset it and everybody is happy again. It is
getting pretty late so I put the machine away.

Any ideas? Everything that was on, kept working. Now I don't know know if it was the field or output breaker but I am guessing by
the flash of light that it was the main.

Pretty hard to trouble shoot a problem that isn't there now, but I am at least going to take a look at the back of the panel with a
mirror for signs of arcing just in case something is loose and bouncing around. (interestingly this happened during one of my better
landings)

Where I was raised, blown breakers aren't something to be ignored.

Mike Z.