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Rectifier/Ground Issue


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Fellow CT Fliers,


After my return flight from the shop which did our annual with no issues and some problems solved, the next flight had the issue outlined below:


"After rotation, we climbed at 5,100 RPM, 80kts IAS on runway heading to 1,100 ft. We then turned to heading 150, continuing the climb to 1,400 ft. After turning on course, the generator light illuminated steadily, and I noticed the volts were in the yellow arc proceeding to red line, then past red line. At the same time, the oil temp indication was climbing into the upper yellow arc, to red line.


At this point I declared a precautionary return to the airfield, continued climb to 1,700 TPA, turned for left downwind for R20, leveled off, and reduced power to 3,200 RPM. The generator light began a random pattern of illuminating on/off while voltage indication slowly returned to the yellow arc. Oil temp indications were in the mid yellow arc, steadily dropping to the green.


We landed uneventfully.


No landing lights were used. Only the avionics, intercom, and beacon were turned on. No circuit breakers were tripped.


I have not taken the cowl off yet to investigate yet. My first reaction is that this is a ground/connection issue.


My question is why would only the Oil Temp indicator go up and not the CHT, and Pressure?



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Hi Chris,


Some sensors and probes are highly sensitive to poor grounds over others. This sounds like a ground issue. There are 5 grounds to tighten. As I always say they are hand tight, but wrench loose until proven otherwise. 4 grounds to tighten are in the engine compartment around the battery area. The air frame one, then it goes up under the starter solenoid, then out the other side to the rec/reg. Then up the firewall and into the instrument panel(the 5th one). Take off the passenger side panel and look straight back against the firewall. If it is an SW it may have 1-2 screws through the firewall. If it is an LS it is a grounding block. Tighten this through the firewall screw really tight. My money says if you put a nice tight wrench on all 5 ground attachments your issue will go away.

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Will do.


I have also ordered tinned braided cable and plan on putting together a star ground configuration much like Marcus outlined in a post some time ago, along with the addition of a dielectric paste and locking washer at each location.


Maybe someday, someone will come up with a universal way to fix this very basic issue, seems like we all come up with something a little different.


The one item i am currently working on is the connection point between the signal wire and spade connection points on our probes.


Information will be posted along with pictures after the suspect point/s are found.


Thanks again,


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Chris, Had the same problem after I had my hoses and firewall blanket installed at the shop you were going to take your plane to last Jan.

Loose (YELLOW) wires on bottom of plug that goes into the rectifier. Also had to replace rectifier due to arcing and melting plastic.

Pull your cowling and check these two yellow wires.

You missed a great time in Page.

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Kind of makes you wonder about Dougs, doesn't it. :rolleyes:




Here is a better product to use on your ground contact points. Stabilant 22




Bob is right to check on the wires going into the Reg/rec. Pull on them fairly hard to make sure they do not come out of the black plug. Then grab the black plug and the body of the Reg/rec with both hands and squeeze it together hard. You need to make sure the male connections are in the female connectors.


There already is a better ground solution. I posted pictures under the maint. pic and video section.


There is also another CHT and oil sender connection if you wanted to switch what you have. You would need to replace the spade connection fitting you have with one that has a nut on it where you can put and electrical eye on your wire on it and tighten it down.



Before you do any switching let me finish testing a new Dynon sensor configuration program this next week. It was only sent to 3 people so it has taken a little longer to get test done.

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Yes, it is an insulator only to be used to protect connections from corrosion. The question was if there was a place where it could/should be used? It is used to protect ignition systems, among other things, in cars and boats. Looks like the stuff you recommended does that job plus enhancing the connection.

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For those who need to know the difference.




DeoxIT® & DeoxIT® GOLD vs Stabilant 22


What are the advantages of the DeoxIT® and DeoxIT® GOLD VS Stabilant 22?




Similarities of DeoxIT®/DeoxIT® GOLD and Stabilant:

1) They are all metal contact/connector enhancers - improve conductivity.

2) They are all good lubricants and protectants.


Differences of DeoxIT®/DeoxIT® GOLD and Stabilant:


1) DeoxIT®/DeoxIT® GOLD are excellent cleaners (without the use of solvents or aggressive cleaning agents).

Not similar to flushing type contact cleaners, DeoxIT®/DeoxIT® GOLD dissolve oxidation on metal surfaces. This is especially important on older equipment and equipment exposed to severe environments (humidity, salt, and other contaminants). Dissolving oxidation lowers contact resistance, thereby increasing conductivity even more.


2) DeoxIT®/DeoxIT® GOLD are ideal for moving and stationary connections.

DeoxIT®/DeoxIT® GOLD are designed to re-coat surfaces that are disturbed (by vibration) or connections that are re-inserted many times (edge connectors, plugs/sockets).


Stabilant is more solid and requires re-application if the connection is disturbed or changed. This becomes very important in high vibration applications (equipment and systems with moving parts, transportation, aviation, etc.).


Following any disturbance or vibration, DeoxIT®/DeoxIT® GOLD will re-coat the surface. There is also no need to treat 100% of the connection. If 80% of the metal surface is treated, the DeoxIT®/DeoxIT® GOLD will spread and seal the other 20%. In fact, if a plug is treated, but the socket is inaccessible, the DeoxIT®/DeoxIT® GOLD will migrate (along the metal surfaces only) and treat/seal the socket.


3) DeoxIT®/DeoxIT® GOLD work well with similar and dissimilar metals.

Many metal treatments require that both surfaces be of the same materials to provide maximum effectiveness. DeoxIT®/DeoxIT® GOLD are formulated to be effective on all metal surfaces, similar and dissimilar.


4) Available in many convenient applicators.

We offer many applicators for our products. Sprays are offered for convenience, as well as affording a way to get to hard-to-reach areas. Since our concentrates are very cost effective, sprays become a very convenient option. Other versions include pens, wipes, needle dispensers, etc. Many applicators are offered in 100% and 5% formulations.


For reference, when our part number has "100" in the number, that represents 100% concentrate, (i.e., D100L-25C, D100S-2, the DeoxIT® needle dispenser and 100% spray, for example).


When the part number includes a "5", that represents 5% of the concentrate and 95% of a flushing solvent,” (i.e., G5S-6, G5L-25C, the DeoxIT® GOLD spray and needle dispenser, for example).


Flushing solvents, as offered in the 5% solutions, are ideal for displacing surface contamination (oil, grease, dust, etc.) and may be required for certain applications.


5) Exceptionally cost effective to use. DeoxIT ® and DeoxIT® GOLD are considerably less costly than Stabilant or other similar polymers.


*CAIG does not recommend using any form of alcohol-derived solvent (they contain water), because these are polar solvents and conduct electricity. If the solvent does not evaporate completely, they may cause shorts. This is especially of concern when applied to porous materials (phenolic, rubber, etc.).

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Cowling off checked yellow wires and they seemed a little loose. Tightened them up and problem did to go away. Tighten all the grounds, no go. Gen light stayed illuminated regardless of power settings. Typically we would see that the light would go off at 2000 rpm.


Trip coming on Friday, new regulator ordered from cps.


Not sure what else to look at?



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