[batata003]

Hi,

I had a crash and bought a new ESC with the same brand and specification. Now when I fly everything works fine but one thing looks weird: 3 ESCs beeps together when I connect power but one ESC beeps at least 2 seconds before all the other ESCs which is exactly the ESC that I replaced.

I am using EMAX SIMONK 20A ESC and they are all supposed to be the same. I re did the calibration in my FC and drone flights fine, but should this create any future problem? I mean, is there someway to make this ESC beep together with the others?

[f5soh]

If all works fine, Esc calibration done and neutral values adjusted, you can continue to fly without issues.

If you want the start issue resolved, assuming all the esc are the same you can flash them with the same firmware.

[batata003]

These EMAX SIMONK ESCs are a pain in the a*** to get flashed, but if you think I will be ok I will keep it as it is

[TheOtherCliff]

If it flies OK ... it is OK. 

Make sure to calibrate ESCs and set motor neutrals when you replace an ESC.

A rule I always follow now (SImonK or BLHeli) is "Test it for DOA, but then immediately flash the latest firmware."  Sometimes they are cheap because they have an old, inferior firmware version installed.

SimonK flashing is easy now.  BLHeliSuite can do it through the servo connector without removing the ESC covering.  Get the particular kind of USB to serial adapter to do this.  I just use an Arduino with a CH340 chip for about $2.25 shipped (that itself must be flashed with certain "sketch", but that is easy via the CH340).

I will say that one ESC would not finish flashing this way and got worse (less flash complete) each time I tried.  I assume it didn't work as well when warmed up normally, so I cooled it in the freezer for 15 minutes and flashed immediately after getting it out.  One other would not finish even after cooling it (I will have to open the cover and use the normal MCU clip which I already have).  These ESCs work fine and I fly them regularly.  I have bought several batches of these eBay SimonK 30a ESCs for about $3.40 shipped each.