Voltage regulator removal

[Guest]

I spent all day yesterday trying to get to the voltage regulator on my early M20J.  I need to get to it to troubleshoot the overvoltage relay tripping. Does anyone have any tips to get to this thing. It appears to be screwed to a piece of aluminum which is perpendicular to the side of the airframe. I removed three flush screws from the out side. I found two more inboard securing it to the tubular structure. I still can’t move it and can’t figure out where it attaches. Unfortunately I can’t find a mechanic who can look at it prior to mid December, so I am trying to expedite…

[PT20J]

Mooney used different regulators and mounted them in different locations over the years. My 1978 J had a giant OECO regulator mounted in a place almost impossible to get out. It might help if you could take some pictures. Then perhaps someone might recognize your installation as similar to theirs.

[EricJ]

I have a 77J.   Mine is difficult to get to, but removing the glareshield should help be able to see where it is and how to get at it.   Mine takes doing the usual contortions under the panel to remove it.   An inexpensive endoscope and/or a mechanic's mirror can be very useful in finding where the fasteners are, etc.  

Since these airplanes are old, it's possible it's been moved a bit over the years, too.

[Guest]

I took the glare shield out. I am going to come back with a borescope!

[201Mooniac]

In my 80 J it is mounted with two adel clamps to a tube in the copilot footwell.  While not easy to get to it isn't too hard.

[Ragsf15e]

1 hour ago, 201Mooniac said:

In my 80 J it is mounted with two adel clamps to a tube in the copilot footwell.  While not easy to get to it isn't too hard.

And if you need to spend any time under there, taking out the pax seat is really beneficial.  Two stops on the inside rail come off.  Then the seat slides forward to get the forward rollers off, then back and poof, it’s out… I could have the forward/backward opposite though.  I always look that up.  Anyway, that helps lay under the dash much better.

[A64Pilot]

On 11/23/2023 at 12:48 PM, Kerrville said:

I took the glare shield out. I am going to come back with a borescope!

Try sticking your cell phone up there and taking pictures

[Yetti]

16 minutes ago, A64Pilot said:

Try sticking your cell phone up there and taking pictures

yep.  also works for being old and trying to read parts tags in hard places.

[Guest]

I think this is it. Have no idea how to get it out. 

[N201MKTurbo]

On my 77J the regulator is screwed to the firewall. You need a helper to hold the nuts on the inside while you screw the screws in the engine compartment.

If you need to get to the stuff on the shelf, the easiest wat to get in there is to remove the right radio rack. This isn’t as hard as it sounds. Remove the radios, then take the screws out of the connector panels at the back of the individual trays, then remove the three screws on the top of the rack and the three screws at the bottom of the rack and slide it out. Then you have easy access to the electrical equipment on the shelf.

[N201MKTurbo]

7 minutes ago, Kerrville said:

I think this is it. Have no idea how to get it out. 

That is your alternator filter.

[PT20J]

11 minutes ago, N201MKTurbo said:

That is your alternator filter.

Agree.

My 78 J had it screwed to the firewall, up high under the windshield combing. It was an OECO and looked like this.

[A64Pilot]

1 hour ago, N201MKTurbo said:

On my 77J the regulator is screwed to the firewall. You need a helper to hold the nuts on the inside while you screw the screws in the engine compartment

I don’t usually have a helper, I use a pair of needle nose visegrips to hold nuts in a case like this, it’s heavy enough to not spin when the screws are turned.

To put the screws back in put a piece of duct tape on the heads, that will hold them in enough to get the washers and nuts started.

I won’t use nut serts myself, but some do.

[Guest]

Good to know. So that is not it…. @201mkturbo, is yours on the firewall interior or on the engine side. I don’t see anything in the engine compartment. 
 

…funny thing also is, I charged the battery today, put it back in, started the plane while my voltmeter was connected to the bus. (I wanted to see what happens.)  I could not duplicate the issue. Now it seems to be working…

[N201MKTurbo]

47 minutes ago, A64Pilot said:

I don’t usually have a helper, I use a pair of needle nose visegrips to hold nuts in a case like this, it’s heavy enough to not spin when the screws are turned.

To put the screws back in put a piece of duct tape on the heads, that will hold them in enough to get the washers and nuts started.

I won’t use nut serts myself, but some do.

I use the same tricks. But this regulator is in a horrible place. I can usually get the nuts in place with a long extension with a U-joint on the end wrapped with tape to restrict its movement. I usually have someone else hold the screw and spin it and then try to get the nut on the end of the extension to start on the spinning screw. 
 

There is no way to get visegrips anywhere near these nuts. 
 

could you get the nuts started on taped in screws? Maybe in the 10th try if you are lucky. 
 

It’s way easier with a helper. BTW, there is always somebody within a few hangars away who is glad to help.

[Ragsf15e]

1 hour ago, Kerrville said:

Good to know. So that is not it…. @201mkturbo, is yours on the firewall interior or on the engine side. I don’t see anything in the engine compartment. 
 

…funny thing also is, I charged the battery today, put it back in, started the plane while my voltmeter was connected to the bus. (I wanted to see what happens.)  I could not duplicate the issue. Now it seems to be working…

Depending on the year/model, they are on the copilot side inside or outside the firewall. It’s tough to see but follow the field wire back from the alternator.  It’s likely high up inside the firewall if you can’t find it.

If it’s working currently, can you get it home and deal with it there?

[Guest]

I’m going to try and fly it tomorrow. Hopefully stays out, but while I have the panel and glare shield apart I am hell bent on finding the regulator. 

[Guest]

I had the battery on a charger today. It is 75 hours old, but 7-8 years on a gill. Could a bad battery cause an overvoltage?  I imagine no, but I don’t know anything about electronics. 

[Ragsf15e]

23 minutes ago, Kerrville said:

I had the battery on a charger today. It is 75 hours old, but 7-8 years on a gill. Could a bad battery cause an overvoltage?  I imagine no, but I don’t know anything about electronics. 

7-8 years?  Im electrically challenged as well, but batteries have been lasting around 4-5 years and gills don’t have a good reputation either (thr newer ones might be ok).  Many people use concorde rg-35agx but even on them 7 years is long ish.  
https://www.aircraftspruce.com/catalog/elpages/rg_35axc.php

[A64Pilot]

A “bad” battery shouldn’t cause over voltage.

The low hours actually are a bad thing. It means it’s been sitting for long intervals between being charged and of course all batteries self discharge.

If you got 7 years out of a Gill that’s very unusual, and overvoltage will more than likely “boil” a wet cell and that means acid comes out and corrodes your airplane.

[OR75]

do you have anything in the panel that monitors the voltage in the bus bar ? (stormscope, engine monitor ?, otherwise it is not difficult to connect a voltmeter)

it should read a steady voltage close to 14V (13.5-14V)

often when voltage regulators fail, it is not a full fail but rather a voltage that fluctuates. Those things can give you the impression that it fixed itself.

[Guest]

I’ve hooked up my fluke and the voltage seems mostly steady at 13.6. I’ve seen it fluctuate with load as low as 13.3 and as high as 13.8, but pretty steady. 
 

is this it here?

[Guest]

Kinda looks like what @Pt20J pictured. Looks like only 3 nuts. Hopefully, if I disconnect it I can fish those other wires up. Looks a lot easier than that filter. 
 

I was wrong on the battery, looks like 5 max 6 years, but sounds like it may be time for a new one of those too. Is the consensus that the Concorde is the way to go?

[Ragsf15e]

9 minutes ago, Kerrville said:

Kinda looks like what @Pt20J pictured. Looks like only 3 nuts. Hopefully, if I disconnect it I can fish those other wires up. Looks a lot easier than that filter. 
 

I was wrong on the battery, looks like 5 max 6 years, but sounds like it may be time for a new one of those too. Is the consensus that the Concorde is the way to go?

Most people like Concorde, yes, but some are trying the newer Gills and I haven’t heard anything negative.

[Bolter]

17 minutes ago, Ragsf15e said:

Most people like Concorde, yes, but some are trying the newer Gills and I haven’t heard anything negative.

In my former J, I ran Gill conventional replaced with a Concorde sealed that lasted +5 years and was replaced proactively with the Gill latest sealed battery because it was an OSH special price.  I went back to Concorde when the Gill was noticeably losing capacity with less than 3 years.  The Concorde was superior by far.