Order Number: 696105
Product Name: F405te
Brand: Matek Systems
Although ordered and delivered last July, I have only just got round to using the flight controller board. this has been wired up correctly to the GPS unit. However, when a 3 cell Lipo is connected, the flight controller emits a loud tone, although the LEDs appear to be setting correctly. When a 4 cell Lipo Is connected again it’s working correctly, but there is no tone.
This doesn’t seem very good as I understood the voltage range is from a 3 - 6 cell.
I would appreciate your thoughts and comments.
I have tried two different sized Lipo cell counts
That is a very strange issue as the board itself does not have any buzzer so should not be making any sound.
May I ask if you checked the FC before soldering anything as per our guide - How do I test my new Flight Controller? (and why it’s important)
The next thing would be disconnect everything from your FC and power it up via USB only and see if it works ok via the PC software (betaflight/inav), and if so then only connect the battery and see if the issue is the same.
Then do a visual inspection of the board to see if you can notice any issues with solder splatter, or damaged components etc… (if you are not sure, please upload an image of the top and bottom of the FC and we can also check).
This will hopefully help us to narrow down the cause of the issue so we can suggest the next steps. Given that its past our 6 month warranty we may not be able to issue a replacement directly but will definately try to help figure this out if we can!
Good morning Alex,
Thank you for a very prompt response.
I have tried as you have suggested and the board powers up with no audible sound. Likewise there is no sound when a 4 cell Lipo is connected.
However, the sound appears when a 3 cell Lipo is connected, either a fully charged one at 4.2v per cell or a 3 cell at storage voltage, ie 3.8v per cell.
It just appears to want a 4 cell power supply, I have not tried a 5 or 6 cell so wouldn’t know about that.
Kind regards
Graham
Hi good day Graham,
Thanks for reaching out to us!
I believe that the input voltage regulator is struggling to supply the FC at its lower voltage limit. I had a look at the spec for this FC and I see it is rated for 3-8S. Which is a little unconventional, most FPV FCs are rated 2-6S.
Can you send us some clear images of the top and bottom of the board and I will send these through to Matek and ask one of their engineers to have a look as well.
One last check, could you unplug your GPS/Compass and check if it still makes the same noise on 3s?
Hope this helps.
If there is anything else I can help with please do let me know?
Regards,
David
Unmanned Tech Support
Hi David,
Still the same with the GPS unplugged on 3 cell and ok on 4 cell.
(attachments)
Hi Graham good day,
I would go with my original comment and say its probably the input regulator.
Can you send me some clear photos of the board top and bottom?
Will send those through to Matek, along with the video and see what they have to say.
Hope this helps.
If there is anything else I can help with please do let me know?
Regards,
David
Unmanned Tech Support
Thank you for your thoughts.
I did email top and bottom images and a short video with the GPS disconnected.
Did you not receive these?
Hi David,
I am sending the images again but this time as an attachment just in case you never received them yesterday.
Kind regards
Graham
(attachments)
Apologies Graham, I missed the URL there.
I have sent the photos and video off to Matek and asked for one of their engineers to assist.
As soon as I hear back from them I will update you.
Regards,
David
Unmanned Tech Support
Hi David,
Thank you for your help and support.
Kind regards Graham
Hi Graham good day,
I have spoken with one of the engineers from Matek. My first question was whether or no the product specifications for input voltage were correct. He said they are correct, bu the 12V voltage regulator struggles at 3S voltage.
This was his comment:
It is correct.
for 3S input, the FC can work. but 12V BEC can’t output stable 12V. That is the character of step-down regulator.
It would seem that the FC is working as intended but the regulator just cannot perform at that minimum voltage.
Hope this helps.
If there is anything else I can assist with please do let me know?
Regards,
David
Unmanned Tech Support
