NEW Alternator issue as older one. Bummer...

[ilikethewoods]

Yes, I've used the search function, I've sifted through items I thought were close to mine and found nothing. If you seen a post with issues like mine, please let me know and I'll delete this one.  I'll keep it simple. As I'm running my aircraft on ground/flying. My voltage meter (battery indicator - shows discharge or charging) the needle is going back and forth very slightly. Once I'm flying and using the boost pump (per the POH-take off's landings) I can hear the boost pump, higher pitch then lower pitch. Basically following the exact tempo as the battery indicator. <<---No, its the not the pump. Please continue to read. 

The panel lights, the over head light go from dimmer to brighter following the exact tempo as the battery indicator as well. My RPM's, MAP's are steady, my engine is not a HOT ROD so it doesn't have a CAM lope. First thoughts were the alternator, stabbed a new one in and my wallet was PISSED! Has anyone ever experience any issues like this before. Thanks.

Alternator SPECS.

ALY-8520R HARTZELL 12V/60A 

[EricJ]

What airplane?   Sounds like maybe the regulator depending on what type you have.

 

[neilpilot]

Do you have a separate voltage regulator?  Is it a mechanical VR?

 

PS - EricJ & I had a mind meld

[Ragsf15e]

The two guys above have good questions for you.  Unlike cars, the alternator in your airplane is likely externally controlled by a regulator.  The old (original) regulators are mechanical.  The newer ones are digital.  The old ones can fail in weird ways.  I’ve been told (by zeftronics tech support) that the digital ones usually either work or don’t work, there’s not a lot of weird failures.

What year is your airplane?  Electrical problems are kind of difficult to nail down but there are good troubleshooting guides on both the zeftronics and plane power sites.

its common (and expensive) to throw parts at these issues before knowing exactly where the problem is.  I did both an alternator and regulator before I quit letting my IA troubleshoot it and read the zeftronics guide myself.  I then narrowed it down and replaced a $25 circuit breaker... after $1000 of alternator and regulator that hadn’t fixed anything.

So circuit breakers wear out, corrosion causes resistance at contacts throughout the airplane, and the field wire lives a hard life between your regulator and alternator (via the master switch).  
 

you need a voltmeter and a troubleshooting guide.

[carusoam]

Usual suspects...

1) alternator...

2) Control wire to the alternator...

3) Voltage regulator...

4) Wire from the voltage regulator...

5) Field wire...

6) Slip/skid of a drive belt for the alternator is next on the list... check the belt tightness...

 

One thing gets mentioned a couple of times because it is popular failure mechanism...

PP thoughts only, not a mechanic...

Best regards,

-a-

[ilikethewoods]

What airplane?   Sounds like maybe the regulator depending on what type you have.
 

M20F. 1976. I’ll look for the voltage refrigerator today and see. Thanks.


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[N201MKTurbo]

Mine was doing that a while back. I tried everything else, but in the end it was the regulator. I'm not saying your problem is the regulator. It can be other things, but mine was the regulator.

[ilikethewoods]

Mine was doing that a while back. I tried everything else, but in the end it was the regulator. I'm not saying your problem is the regulator. It can be other things, but mine was the regulator.

Sweet, thanks for the quick reply! I’m thinking that at this point. New ALT, new belt as well. Links in the chain...


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[Guest]

It’s often discussed here, the field control switch used 1/4” push on spade connectors which come loose, and the internal contacts become pitted, both can cause what you’re seeing.  Find the terminals on the switch and connect a jumper cable with alligator clips across them and run it up again.

Clarence

[Yetti]

Start with the easy stuff.  The belt.  Check belt wear and alignment.   My alternator bracket was installed backwards.

Then check the wiring.   Build a new wire harness. 

Could be as simple as a loose/corroded connection.

[Ragsf15e]

12 hours ago, Yetti said:

Start with the easy stuff.  The belt.  Check belt wear and alignment.   My alternator bracket was installed backwards.

Then check the wiring.   Build a new wire harness. 

Could be as simple as a loose/corroded connection.

In fact, the belt or a corroded connection (or circuit breaker) are most likely.  Unfortunately, tracking down the actual culprit corroded connection in 169 miles of wiring stuffed into a 50 year old volkswagon with wings is the difficult part.

That being said, changing from the old mechanical regulator to a digital (plane power or zeftronics) isn’t terrible.  It’s ~$300 and easy to do.  Should last and be reliable too.  Checking input voltage and output (field) voltage from the regulator is definitely part of the troubleshooting.

[podair]

17 hours ago, M20Doc said:

It’s often discussed here, the field control switch used 1/4” push on spade connectors which come loose, and the internal contacts become pitted, both can cause what you’re seeing.  Find the terminals on the switch and connect a jumper cable with alligator clips across them and run it up again.

Clarence

That's exactly what happened on mine, after I replaced the alternator of course...

[Ragsf15e]

9 minutes ago, podair said:

That's exactly what happened on mine, after I replaced the alternator of course...

Yeah, I think that’s common.  A lot of mechanics see electrical problem and go straight to the alternator.  It’s relatively easy to wrench and doesn’t require any further troubleshooting to track down a part for replacement... there it is, replace it.  Unfortunately, I think it’s more common that there’s another culprit, especially on the older airplanes because there are lots of corroded connections, switches and circuit breakers.

[Paul_Havelka]

The local auto parts store was able to test my alternator and confirm it was bad.

From a Piper Cherokee

Me:  I need you to test my alternator please sir.

Parts guy: What's it off of?

Me: Uhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh.  1972 Chrysler 400bb

 

[J0nathan225]

24 minutes ago, Paul_Havelka said:

The local auto parts store was able to test my alternator and confirm it was bad.

From a Piper Cherokee

Me:  I need you to test my alternator please sir.

Parts guy: What's it off of?

Me: Uhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh.  1972 Chrysler 400bb

 

Anywhere that will repair your "Chrysler Alt"? I'd like to have mine as benchstock, pretty sure it's a failed diode. 

[Paul_Havelka]

Any local motor, starter, alternator repair shop should be able to fix it.  I just replaced with a plane power unit

[mooniac15u]

Here's a more detailed write-up on what @M20Doc described.

http://donmaxwell.com/fluctuating-ammeters/

 

[Guest]

3 hours ago, Ragsf15e said:

Yeah, I think that’s common.  A lot of mechanics see electrical problem and go straight to the alternator.  It’s relatively easy to wrench and doesn’t require any further troubleshooting to track down a part for replacement... there it is, replace it.  Unfortunately, I think it’s more common that there’s another culprit, especially on the older airplanes because there are lots of corroded connections, switches and circuit breakers.

The other flip of that coin is owners who don’t want to pay a maintainer to read a manual, think and diagnose.  We can’t know everything, reading and studying is required.

Clarence

[Ragsf15e]

2 hours ago, M20Doc said:

The other flip of that coin is owners who don’t want to pay a maintainer to read a manual, think and diagnose.  We can’t know everything, reading and studying is required.

Clarence

Well yes, that’s definitely true.  I was hoping you wouldn’t take offense to what I wrote because your guidance on this board has always been spot on and backed up by manuals, diagrams, and regulations.  Just so you know, that’s not exactly typical.  Heck, even your magnetic paperclip trick to check the alternator is more than my mechanic did before replacing it and I consider him to be fairly “by the book”.  I think diagnosing electrical systems can seem like a dark art.

[Guest]

2 hours ago, Ragsf15e said:

Well yes, that’s definitely true.  I was hoping you wouldn’t take offense to what I wrote because your guidance on this board has always been spot on and backed up by manuals, diagrams, and regulations.  Just so you know, that’s not exactly typical.  Heck, even your magnetic paperclip trick to check the alternator is more than my mechanic did before replacing it and I consider him to be fairly “by the book”.  I think diagnosing electrical systems can seem like a dark art.

No offence taken.

Clarence

[ilikethewoods]

Well, this wasn’t my alternator problem, more of a “master switch” problem. Instead of making a new thread, I decided to post these photos here.

Problem: hit master switch off & power would stay on.

Solution: clean the heck out the cannon plug until it looks brand new!

Problem: fixed!


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[ilikethewoods]

17 hours ago, mooniac15u said:

Here's a more detailed write-up on what @M20Doc described.

http://donmaxwell.com/fluctuating-ammeters/

 

I just found that article today. I'm going to start using Google more, instead of wasting members time. Thanks for link, and help. Stay up..

[Marauder]

Well, this wasn’t my alternator problem, more of a “master switch” problem. Instead of making a new thread, I decided to post these photos here.

Problem: hit master switch off & power would stay on.

Solution: clean the heck out the cannon plug until it looks brand new!

Problem: fixed!


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Did you by chance take a look at the Canon plug on the regulator? Thats where I found a lot of my corrosion. BTW - if you do have a regulator failure, I highly recommend the Zeftronics R1530B. It is a direct connect replacement for regulators with the Canon connectors.




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[ilikethewoods]

Thanks! I’m going today to knock out some more items on the bird. I’ll definitely check it today.


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[carusoam]

Great pics!

Looks a lot like corrosion found on battery terminals?

Asking a mechanic if using that battery terminal grease would be a good idea...(?)

PP thoughts only, not a mechanic...

Best regards,

-a-