Toilet Bowl Flushing Update

[DCH]

We can rule out the GPS/Compass board as the cause of Toilet Bowl ...Or even a player in the issue.
I have two Typhoon Hs, a Pro that works perfectly and recovered crash victim the "PhoenixPhoon" that suffers from TB.

While installing the External Antenna kit on my Pro (which turned out great!), I decided to swap the top cover -with GPS/Compass from the Pro and the PhoenixPhoon while I had it apart. No change at all in flight characteristics to either craft. PhoenixPhoon still had TB and the Pro flew flawlessly.

I originally bought the PhoenixPhoon for parts but decided to fix it as a spare, so all is not lost if TB is incurable because I can sell off all the extra parts I don't need. However I have the unique opportunity to experiment with the PhoenixPhoon -a complete flying test lab to attempt to find the cause and cure for TB -if anyone still cares. But my knowledge of the Typhoon electronics and their layout is very limited, so I don't know where else to poke and probe it, besides the Main Control board, but that's expen$ive to just replace on a hunch, and I'm not ready to try to pull it from my Pro.

If no cause/fix has yet been established for TB -which reading here seems to be the case- and TB is still an issue in a few birds, I'm willing to pursue this deeper with some guidance from those with interest and more knowledge of the various subsystems than I have.
I am wide open to any suggestions, and so is the PhoenixPhoon now, quite literally.

 

[CraigCam]

So when does your wonky one go bad? All the time? I ask because I have a repaired H that is suspect in a similar fashion. It’s actually quite flyable as usually a good stick move and direction change stops the circling. This one also has been like you, swapped out for GPS from a good working unit and the problem remained with the wonker and the good one stayed good. Similar install of extension on a Pro even when I swapped. I’ve pulled the camera on it and installed an FPV rig for my Fat Sharks instead which is not as fun to be in the cockpit of as I thought it would be. But that’s another matter entirely as the flight system of the H is why it’s weird in goggles even with the non latent real video signal. If I had sport mode like the Plus does it’d be way more fun.

 

[DCH]

It starts out fine every time, smooth and stable flight and hover. Somewhere around 5 minutes into a flight it starts to orbit in a circle when left to hover. If left on it own the circle increases as does the speed of the swirl. I can only let it do this a short time because I have a forest fence and it would crash into the trees.

I can fly it around and it will stop the swirling, but the stick response seems reluctant and jerky, and it starts to twitch violently intermittently. Switching GPS off stops the oscillations, but they resume immediately when GPS is turned on again, no additional 5 minute wait once TB has started.

I have tried with full batteries, and half charged batteries, but it's always around 5 minutes into a cold start flight, so in my case it's time related not voltage related. This suggests that it is the increasing internal temperature from flying that triggers it. But we still don't know just what "It" is being triggered yet.

 

[Steve Carr]

But we still don't know just what "It" is being triggered yet.

When the GPS module doesn't fix the TB, the next suspect part is the Flight Controller. It plugs into the top of the main board. I have seen faulty FC's cause some strange problems even including camera tilt issues. If you watch eBay sometimes you can pick up the whole main board with the FC included.

 

[Rubik]

I did a search for toilet bowl issues here and there does not seem to be a definitive solution out there except maybe a flight controller that overheats.

I recently replaced my drowned TH with a refurbished airframe from ebay. I've had 6 flights and 3 have had various degrees of TB. As with DCH, it always started after several minutes of rock stable flight. This last flight scared the cr*p out of me. I was flying at a new location, a large gravel parking lot near the Yakima River about 130 miles east of my previous flights. So, I did a compass calibration. After several minutes of stable/controlled flight, the TH was hovering about 150 ft. above ground while I did a gimbal pan. We noticed that is was starting to fly in circles. As I brought it down, the circles got larger. By the time I was within 15 ft. above the parking lot, the circles were 20 ft. in diameter! I wasn't able to keep ahead of the gyration with the controls so I decided to just bring it down as gently as possible when it was well away from a parked car and some large rocks marking the border of the parking lot. When it touched down, it did not react normally to the red button but hopped around like a chicken with its head cut off for a while. It finally stopped on its side. The camera popped off but there was no real damage.

The TB has happened with different batteries. For this last flight, I came down while there was still plenty of voltage (14.7v). I had 19 satellites at take-off and 20 at landing. There were no large metal objects nearby (besides, latest TB started 250 ft. in the air). The telemetry file shows brief, intermittent compass calibration errors showing up near the end of the flight. I've been flying TH for over 3 years (see YT channel: Rubik3x).

I may have to go back to the ebay seller and say there is something wrong that doesn't show up until the system is all warmed up. Any new thoughts on this?

 

[DCH]

My thoughts are this. First of all, when the H is experiencing TB, all you need to do is turn the GPS off and fly manually. It will fly normally and land normally.

This would suggest that the GPS board is at fault, but that is not the case. I had two H480s that I could swap parts back and forth from to isolate the problem. Long story short, I discovered that the problem only resided in the main flight control board, not the GPS board. So I bought a flight control board from ebay for $30 and the problem was completely solved.

 

[DoomMeister]

I’m on board with Steve Carr on this one. The likely culprit would be the FC board. I have seen several cases of the FC board being the cause of GPS Acquisition problems.

Looking at the parts list for the H/H Pro and H+/H520 both have the compass and GPS on the same board. Since swapping that board makes no difference in the behavior of the good and wonky aircraft, that pretty much narrows the problem down to the FC board. For the H/H Pro that would be YUNTYH133SVC. It is possible the Main ESC board could have some heat sensitive solder connections causing the trouble, but that seems a less likely possibility.

I think my first course of action would be to lift and reseat the FC board a few times and see if the problem disappears. If not, then try finding a replacement FC board.

Edit: @DCH snuck that one in there while I was typing my response. Good swaptronics on your part DCH.

 

[Steve Carr]

I've repaired two H's in the past 8 months with exactly the same problem you have described. I've tried reflashing the Flight Controller and that has not fixed the problem. I suspect both of these aircraft were subject to overheating. Even in mild climates if the H is left in a trunk in the sun it will get extremely hot.

Shop for a replacement FC. A crashed H is the best find.
I should add, this anomaly is not common so long as the firmware is current.

What did you do with your drowned unit?

 

[Rubik]

I've repaired two H's in the past 8 months with exactly the same problem you have described. I've tried reflashing the Flight Controller and that has not fixed the problem. I suspect both of these aircraft were subject to overheating. Even in mild climates if the H is left in a trunk in the sun it will get extremely hot.

Shop for a replacement FC. A crashed H is the best find.
I should add, this anomaly is not common so long as the firmware is current.

What did you do with your drowned unit?

The drowned unit is still sitting at about 60ft depth in the Columbia River (Lake Entiat) .

I checked that the replacement unit with TB issues has the current firmware. The ebay seller has agreed to replace the suspect flight controller and thoroughly test the TH before returning it to me.

 

[Steve Carr]

Outstanding. The seller appears to be knowledgeable regarding the H.