I got a chance to fly a couple packs yesterday, and I had the below anomaly occur when plugging in the battery.  I first get the normal tone.  Then I get a second partial tone.  This has never happened before.  I wasn't touching the quad that maybe would have caused this due to a loose connection.  The quad flew fine on both packs.  Ideas what caused this?  Anything to be concerned with?

Are you ESC's on that build singles? Could be one is initiating slower than the others, or it rebooted the ESC board in the case of a 4in1.

Does it happen on every power up cycle?

(19-Jan-2020, 03:03 PM)kaitylynn Wrote: Are you ESC's on that build singles?  Could be one is initiating slower than the others, or it rebooted the ESC board in the case of a 4in1.

Does it happen on every power up cycle?

It is a 4n1, and this is the first and only time it has happened.  It's on my Super G+, so I only have 6 flights on it.

The last two beeps denote a throttle signal detected from the FC (i.e. a signal connection to the ESC). What you are hearing is a delay with one of your ESCs getting that signal. You can tell it is just one delayed ESC because the first set of tones can clearly be heard as a harmony of more than one ESC playing the tones, whereas the delayed two tones at the end is a single set of tones coming from just one ESC.

The question of these delays has been asked of JB a number of times on his live streams and he says it's nothing to worry about. It's something that just happens sometimes. It's only the ESC initiation sequence that is delayed which doesn't affect normal operation of the ESCs after the initiation is complete. I sometimes experience the same on one of my whoops although not quite as long a pause between initiations as in your example. It never seems to have had any effect during the actual flights.

Thanks guys for the answers!

The biggest problem is, if you're anything like me, my OCD goes into overdrive whenever the tones are out of sequence and I start getting all upset for no good reason 

I have had singles do this, but I guess a 4in1 really is just a single board with 4 ESC's on it. Is there any debris in the motor?

(19-Jan-2020, 03:35 PM)kaitylynn Wrote: I have had singles do this, but I guess a 4in1 really is just a single board with 4 ESC's on it.  Is there any debris in the motor?

Nope, pristine motors....

(19-Jan-2020, 03:33 PM)SnowLeopardFPV Wrote: The biggest problem is, if you're anything like me, my OCD goes into overdrive whenever the tones are out of sequence and I start getting all upset for no good reason 

Yes!  And the burden is real!

I get this every now and then, and I swear it's happening more regularly since Betaflight 4 and/or RPM filtering.

Same here. Doesn't really happen on my large quads, but my toothpick does that in maybe 50% of cases. Sometimes it's delayed by a few seconds, sometimes it isn't delayed at all. But as the folks above confirmed, it has never caused any problems. I wouldn't be worried.