I discovered this fix about a year ago and posted this here on the forum: 2Cent Solution to C23 Gimbal Buzz!
I used pennies at the time, but it is a viable fix that works and I use it to this day. While experimenting, I discovered that it was the azimuth motor that was buzzing, and that it didn't matter where the weight was on the gimbal, so I put the weight under the gimbal slip ring, above the camera, centered on the gimbal pivot. This reduces the weight leverage of the arm exerted on the slip-ring bearing, and gave it a more streamlined appearance.
Sorry about the length, I was about to post this as a new thread on C23 Gimbal buzz when I saw this post, there is a lot to explain, it should clarify the issue somewhat, and it may help someone like @WTFproject track down a cause and cure.
I am almost ready to abandon the idea that firmware is the problem or the fix, but there still could be a chance it effects it a little. It seems that the buzz is an issue with individual gimbals as I have suspected for quite sometime. For whatever specific reason we still do not know. It remains possible that firmware tweaks might resolve it, however I am skeptical and think that gimbals with buzz issues need to be calibrated/re-calibrated on an individual basis. Unfortunate that the H Plus app did away with gimbal calibration.
I have just tested and proven this with a substitute C23 camera. First let me thank @Steve Carr
, possibly the most generous person I have met on the forum, for giving me a C23 to test. Now Steve may very likely be under the impression it is on loan to me, but anyone who knows me can tell you what a procrastinator I am, and the likelihood of me ever getting around to sending it back are extremely rare, ...pigs will already be fling by then!!
Before testing I put both cameras and the aircraft outside on the porch for a couple of hours to soak to an ambient temp of 45°, to insure maximum potential for buzz -which experience has shown me the buzz is always worse when things are cold. I powered mine on first, and believe it or not, the buzz was heard all the way down in Florida by @Ty Pilot
, who told me over the phone after the test that he heard it clear down there! Okay at this point I should mention that by coincidence Ty had just called me for a chat as I was about to perform the test, so he hung on the phone, nervously biting his fingernails nails for the moment of truth. Still the buzz was quite loud, just ask Ty who had no problem hearing it over the speaker phone 3,000 miles away!
Next I mounted the C23 that Steve so graciously gave to me and nothing, not even crickets! Completely silent save for the whisper of the fan. I ran it thru all of its range of motion and still nothing. Even after mounting my aftermarket filter and counter weight there was still no buzz. My new C23 (from my new best friend) works perfectly on my Plus. Thanks Steve!
: I can only speak for my gimbal, but I strongly suspect the issue is the horizontal motor in all the problem units. With a delicate touch I can feel the the vibration is coming from this motor. Also if I apply slight side force to give it something to push back against the buzz stops. And even though I can make buzz come and go with the tilt control at certain positions like the OP noted, the buzz always goes away when side force or down force/weight is exerted/added to the assembly, even if it's the bottom of the camera. It doesn't care if it's out on the back of the arm like the OP's photos, or stuck right under the slip-ring pivot. It can even be the combined weight of a filter and counterweight. it's a matter of total weight. With enough added weight my gimbal does not buzz at all. With no extra weight the buzz is so bad it nearly becomes a chatter. Since weights appear to be a permanent fixture on my C23, I have used flattened led that I shaped to fit and installed with 3M 2-sided mounting tape.
brought up camera balance. Though very important, it is not the cause of buzz. I stacked filters and a lens cap on the good camera from Steve, with no counter weight, and found it will tolerate an imbalance clear to the point of not physically being able to correct it, with no buzzing. It will give up and go limp first.
Photos show my filter counterweight and my center gimbal weight. The combo of the filter and two weights has stopped my gimbal from buzzing.
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