After startup, my trustworthy Piper Archer II lights the “ALT” indicator on the annunciator panel. There is no output from the alternator. However, when I turn on consumers until the bus voltage goes to around 12,2V-12,3V it starts to output and the “ALT” lights goes dark again.
The problem has been there, more or less, for a while – strangely I am the only one who has noticed…
I am very lazy, and it is very cold and dark outside, so I need to troubleshoot this in the easiest way possible… Any suggestions?
Alternator seems fine, suspect overvoltage relay or charge relay/controller/regulator.
G
Search on some other alternator topics, perform GOOD measurements and don’t start replacing parts for no good reason.
Good advice from Jesse about not replacing parts until the problem has been positively identified but the first place I would look is the alternator diode pack.
A_and_C wrote:
Good advice from Jesse about not replacing parts until the problem has been positively identified but the first place I would look is the alternator diode pack.
That would require opening up the alternator, or do you mean the diode that Piper uses for sensing?
Measure field and positive voltage, at the alternator (requires extension leads an two analog meters to do the best job) gives the best results. Some of this issues just can’t been seen on the often used digital meter. While digitale meter is good, one should also have an analog meter IMHO.
If this is not available, measure field voltage at the alternator, with the engine off and battery and alternator switch on, it should be around the same level as the battery with the engine off.
The moving coil never lies
That AVO shows your age 
It also has the capability of sorting the men from the goats, because you can switch it from a voltage range to a current range just by turning the knob, which then blows it up 
Absolutely correct! That’s why I don’t have one anymore. Baaa….
