Had a flight yesterday morning, tried to have another one later, but the board wouldn't power up at all.
Just checked now and the output rail is dead, it'll power up fine with 5V on the input rail. A couple threads mention a diode that may have gone, if this is case I presume its the diode next to J1 labelled B26.
If so what with what do I replace it, I see there's a few different types? (Please note I have the equipment and am fine soldering SMT components.)
What would cause this to happen, nothing has changed after 100+ flights, now suddenly it dies?
The part number of that diode is MBR0520LT1G. My board is out of the 90 day warranty that is offered by 3DR so either way I can't send it back.
I haven't removed the diode, just checked it in-circuit (with a DMM) and it seems open circuit both ways. There is 0.998V on the input rail with JP1 on
Now...help me out here, what would be the best way to do fix? Replace the diode or could I put a jumper across (bringing +5V and -) from the output rail to the input rail? Do I still need to use JP1?
My local supplier has stock of that diode and it costs US$0.10, to send my APM back it'll cost me $25.
So $0.10 and one day or $25 and 5 weeks? Seems like a no-brainer...
What exactly does JP1 do, if the diode is gone do I still need to remove JP1 to power APM2 with the input rail?
It's like talking to myself...
Only saw this now, did this happen after a crash ? or just at random ? I know of a few power issues on the APM2. i have a bunch of SMC doides fresh in form supplier we can try see if have the correct one if you want?
Hi Johann, I think it started with a problem with the Rx, see my latest update. I can get more diodes but they're a b1!ch to replace as space is VERY limited.
I want to try figure a way to power APM2 in another way but don't want to blow something else.
I managed to get a couple of the diodes (MBR0520LT1G) and replaced it, board started fine. However plugged in a camera tilt servo into CH6 of my Hitec Optima Rx and the APM2 board went dead. (The Hitec Rx’s have a supplementary power supply for telemetry/electronics). I then discovered that something is weird with that particular Rx it also appears dead until a servo is plugged into CH6 then it works but seems to cause some current to flow blowing the diode again. I have replaced that Rx.
Tried again with the new Rx but the diode has gone again as the board won’t power up from the output rail anymore. I only bought 2 diodes. It will power up from the input rail.
So I need to power APM2 from the input rail but my ESC's are the only source of 5v+. Can someone tell me if I can bring + & - 5V from the output rail to the input rail?
as far as i know on the old APM1 the output and input power rail were all connected, i think to answer your question we will need to look at the wiring diagrams for the board if they are available, that is.
I've only seen the eagle files but never a circuit diagram...
okay after doing a small bit of detective work this is what i found.
notice all the green area's highlighted , they are all connected and can be de selected by the jp1 jumper if i understood the manual correctley . the only perpose for the diode and jumper as far as i can see is to enable you to use a external battery to power the output rail the the rest of the board and the diode just stops the input power from reaching the output rail. in my opinion you can just bridge the jumper and diode but you wil have to make sure that the input/output voltage does not ever exceed 6v . might be a good idea to use a 5 v regulator like a 7805 i think its called. but i stand to be corrected.
hope it helps
Thanks Johann, yes that really does help, I'll check the voltages tomorrow. As my output rail is always and only powered by the ESC's the voltage should never go over 5V (in fact I measured it at 5.04V) so it should be fine.
Hello just now i have found this because i have the same problem: work fine from the USB, work fine from the input pins but when i plug the 5v from the ESC to the output pins..... nothing! All dead! So it work just do a "can just bridge the jumper and diode" like you have told?? Please in the picture is something like this??