I've had this (how to validate) question from others new to the
P4P. When discovering a gimbal issue in my
P4P at 24 days old, I thought this subject deserved some time to help pilots validate their
P4P purchase. Please help by adding more suggestions to this list if you have others anomalies I haven't heard of. This will help create a "check off" list for those that buy
P4P's, especially from Best Buy who seem to have the worst luck of poor quality from DJI.
Please understand, I think the
P4P is the best all around drone available. This list isn't meant to erode the image of
P4P, because it really is an awesome drone. Although this particular DJI design is superb, the manufacturing quality from DJI isn't consistent.
Here's what to test for when you get your new craft. Return it immediately and exchange it if you don't want to wait 2 to 4wks from DJI for warranty repair, and potentially new firmware you may not want.
1.
GIMBAL FLIP. This exhibits itself mostly during high speed flying, and more at high speed when also turning left hard. Sometimes it will happen when hovering and simply yawing left of right, fast. What you'll see is your camera flip sideways 90 degrees for a few moments. This was a more frequent problem on early production craft, but many pilots still have it. Some pilots see this issue less frequent, and only when you try to make it happen, like me, so they live with it. Mine is to infrequent that it doesn't bother me. I have really try to make it happen, and then I can only see is about 10% of the time. So when I fly normal I never see the issue. Other pilots report this as more spontaneous without trying, it's very annoying. With OA enabled, you have a top speed of 30mph. You should never see this flip problem below 30mph. If you do, return it.
2.
CAMERA RECORDING GLITCHES TO SD. This happens mostly when recording 4K video at 60FPS and 4096X2160 mode. It will occur about 15 to 20 times per flight. It appears to be the inability of the camera to write data to the SD card fast enough. It's not an SD card problem, as it does this with the finest and fastest cards on the market. When recording in 4K at 3840X2160 it's not a problem at 60FPS or 30FPS, so you need to simply always use 3840X2160 to have glitch free recordings. Many craft have this problem using 4096X2160, if yours don't, you're very lucky. This may be a firmware problem that hasn't been resolved yet, so this problem is NOT worth returning to exchange, since practically all of them do it, it's simply a wart to live with. Recording 1080 at 60FPS also works OK, no problem, and it's easier for newbies to edit.
3.
GIMBAL VIBRATION. It took me almost a month to figure out I was getting jello in SD video from a gimbal vibration that's actually a H/W problem. Not all craft do this, but some do apparently. This is easily tested in your bedroom, no props, motors off. Simply turn on the craft and let it finish initialization. Pick up the craft from the top, then tilt the craft left, right, forward, backward about 45 degrees in all directions, which are normal angles during flight. If you have the problem you'll here a hum, and you'll hear it come and go as you tip it in that certain direction. When you touch the camera you'll feel the vibration. My particular symptom was at a 25 degree tip down on the left side. I doesn't exhibit the hum when tipped forward, rear or to the right, only left. The problem is the HUM noise that causes vibration is not apparent when the craft is far away, and the problem doesn't show up in the iPad display because it's such a fine vibration. But in the SD video, if you have the gimbal hum and vibration, you'll see the fine jello come and go as the hum/vibration occurs in the air. DJI replaced my gimbal/camera under warranty, works fine now.
There is also a symptom described as a "gimbal squeal" which doesn't seem to cause jello, it just makes a heck of a noise. Sometimes I can hear the squeal when I land, but I see no affects in the video. My P4 doesn't ever squeal, only my
P4P.
4.
CROOKED CAMERA. With the craft turned on ready to fly, looking down from the top of your drone, the camera should be pointing straight forward. Many craft are built with the camera pointing left or right 5 to 10 degrees. A dual axis gimbal calibration can fix this most the time. There have been reports of DJI recommending to simply twist the whole gimbal in the opposite direction and it will eventually slip and scoot into place, but most guys are too worried it will break first. IMO, if the dual axis gimbal calibration doesn't fix it, then return for exchange with your vendor, or return to DJI for repair.
Double gimbal calibration is first executing the calibration steps on a level surface, but with the craft front pointed straight up, balanced on two motor arms and two motors cases (see SteveNPhx photo below in next post). When balanced, the craft is pointed facing up, but not exactly straight up when balanced. That good enough though. After that odd calibration is completed while point up, then immediately do another calibration with the craft sitting level on the same level surface. This dual calibration trick worked for me, and it has reportedly worked for others
5.
GIMBAL CALIBRATION SUCCESS. Make sure the gimbal will complete a calibration cycle on a level surface. This is fundamental to the gimbal integrity. If you ever get a "gimbal obstruction" warning, the craft may not be able to complete a gimbal calibration, which means it's time to send it in to DJI for repair.
6.
HORIZON TILTED WHEN FLYING SIDEWAYS. This issue is sometimes hard to avoid. Some craft simply cannot avoid some horizon tilt flying sideways, other craft, lucky craft, don't have this problem as much. Make sure you have a good IMU calibration and the gimbal finishes a gimbal calibration on a level surface. With those two done, test the gimbal for level to horizon while flying sideways. This problem haunts DJI the most IMO. It seems like a sensor issue, I get this issue from time to time, but others get this way worse than others. So you'll have to make a judgement call, based on the severity of the tilt and the frequency of the problem. Don't forget, hold C2 and turn the photo wheel to change the horizon tilt while flying. Sometimes that helps.
7.
BATTERY COMPARTMENT INTEGRITY.
There are reports of battery compartments not being molded correctly. When installing the battery some craft exhibit a sloppy fit, with gaps around the battery edge. In these situations the battery is loose and can move around a little after it's inserted
and latched. It's hard to describe what is tolerable and what is not, but if the battery feels snug when installed, that's good. If the battery doesn't feel snug, try another battery. If the second battery is not snug, then you may want to return the craft and try another one. The fear of a sloppy battery is it ejecting during flight due to vibration. Although mid-flight power loss is rare, it may potentially cause power loss due to a loose battery fit. So far it's unproven that batteries can eject during flight, but mid-flight power loss does happen on rare occasions. A sloppy battery fit is a confirmed anomaly that occurs, some craft exhibit this bad fit. A loose battery fit is a feasible explanation of mid-flight power loss, but this could also be from pilot error, installing the battery haphazardly.
