Rectifier on 912 Faulty ?

Hi All,
I have a 912 uls it's setup with a rectifier, a capacitor and an in dash alternator malfunction warning light.
Normally the alt warning light would come on when you turn the master on , then go out once engine started.
I noticed while hanger flying and resetting the clock ,and such, that when I turn on the master , I have no alt warning light ( engine not running , it should be on).
I pulled the bulb and socket, I have a good bulb and socket is getting 12.7 volts .the voltage seems not to be consistent or there all the time.:confused: anyways my light does not light up and I am suspecting my rectifier. I plan on doing an engine run up, with measuring voltage off battery before start and when its running.

Any experience, stories with a bad rectifier, the signs and symptoms of , would be appreciated. I also would very much like a wiring schematic of your similar setup if available. Thanks Kevin

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Originally Posted by kmach

I also would very much like a wiring schematic of your similar setup if available. Thanks Kevin

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Here's my wiring schematic if that helps. Not sure 100% about your rectifier problem. Guess I would check the voltages both running and not. Also you might check the Rotax manual as it has a section on the electrical system that may be helpful.

http://www.teamkitfox.com/Forums/pic...pictureid=2584

Thanks Andy,
I did find allot of info in the rotax heavy maintenance manual section 74-00-00 . including a wiring schematic that duplicates what I have. I as of yet have not had an opportunity to get the aircraft out to test the charging circuit , we have been getting crazy high winds here the last few days ! I am very anxious to test the system out. I am almost sure it is the rectifier, I am thinking of ordering one and a capacitor and change them both. Thanks again ; Kevin

Today I cleaned all the grounds associated with the rectifier and capacitor, re- soldierd a connection on the capacitor, and removed the rectifier connection and cleaned the terminals. tried the master still no alt warning light. I then ordered a rectifier, trying to get it here before the long weekend!
Later the winds let up here a bit so I got the plane out to run it. I hand purged the air out of the crankcase,it took a few turns its been sitting awhile, got in it, turned on the master, and low and behold the alternator warning light was on.??:rolleyes: It went out (as it should ) when the engine fired up. the system is charging and everything is working fine. I synchronized the carbs so a few starts and stops and everything is lighting and going out when it should. So it looks like I'll have a spare rectifier! :o Kevin

The problem turned out to be a dirty master switch. I learned allot about my wiring ( I am not the builder) and the charging system , so that is good .