Yes, fets can fail in 2 main ways, open or closed, one gives no motor the other can cause it to go full speed or occasionally slow speed. Sometimes they actually explode in a tiny way leaving a small crater on top or worse!
@madman1412 is a great source of info on fet replacement, I generally try to replace like for like and just the one that failed.
So what options am I looking at? How much do Fets cost and where should I start looking for some?
Check this thread, there’s info and links on the correct replacement and how to do it.
Did you mean to link one?
Oops forgot the link, at work so a bit distracted lol.
Here it is
So I ended up ordering a new board as I might try and fix this one up later for some other quads, however what went wrong and what should I be cautious about on the new one, other than making the bare wire less exposed. Do you think that when I plugged the usb and battery in at the same time that could have done it? I just really don’t want to do this again to the new board.
Some of the older V1 boards will smoke, but it’s been proven here @FIN13 I believe and it didn’t smoke.
It was most likely a short, I’ve done it, and many here with me. Welcome to the club!
Good news is save that board, for .35c you can get it flying again.
I use hot glue to insulate and protect. It’s easily removed with a few drops of alcohol.
I learned about heat resistant silicone wire from @chrisdo a few times, and also using tweezers to absorb heat so it doesn’t transfer up your wire.
Also would it be worth my while to solder the wires from the underneath of the board. So basically putting the wire though the holes in the contact points and then just soldering the bottom and isolating the motor wires from everything else? Just a thought.
You can solder the motor wires through hole, but don’t need to.
Maybe think about installing some motor sockets and use motors with plugs. Makes changing motors easier.
Also it’s important to have good solder equipment. If you have a decent soldering iron with a fine chisel tip, good solder and some flux it’s way easier to get the job done properly.
When you solder, be fast and don’t heat up the pads to long.
Don’t be too frustrated, as @Kamsleo69 said, we all gone through things like that.
Here is a picture of what a exploded FET did to an AW FC. This is one of the most extreme cases that I have seen of a FET going nuclear and the good news is…It was fixable even though part of the trace was missing. This pic is after what was left of the FET was removed, it was mainly vaporized and only left the contacts that were soldered to the pads.
Here is a shot of the repair by using some 28G magnet wire to jump the broken trace.
Good news guys, got the new board and didn’t make the same mistake. We are up and flying. Another question I have is about fpv gear. I have heard the same cameras that use 5v fry the board or something like that. Any ideas/suggestions. Was really looking for an all in one system as I’m slowly running out of room lol. Thanks guys for all your previous help and advice!
I believe the scisky 5v out does not provide enough amperage to effectively power the FPV is what I heard. So you would want to tap the power direct from the battery with a pololu rather than trying to tap power from the onboard power supply. I can recommend this AIO cam from banggood as I have 2 of them and they perform quite well. Also they are cheaper than trying to DIY one.
General rant: Screw scisky. I’m so fed up with it it’s redixulous unreliability… I’ve now been through 4 of them, 2 were my fault, the other 2 just died randomly on me during flight with no indication of magic smoke or any burnt or blown FET or anything… I’m truly ordering 2 alien boards as soon as my paycheck clears…
Edit: that all in one 200mw Vtx flight cam that @madman recommended kicks arse btw.
There’s also the TX01 with 25mW (draws less current than Tx02, otherwise the same thing) and the new heavier tx03 with switchable output power.
I use TX01 and tx02 with great results. With cloverleaf and with whip/dipole antennas.
Also waiting for some boldclash f-01 to come in (25mW, lighter and with whip antenna), will see how these perform.
You can connect them directly to the FC battery pads. No vreg needed.
Cheap and good.
I don’t understand why the scisky can be so finnicky… my quad will fly perfectly for about 2-3 minutes then it drops out of the sky and I get just a solid red light and no more communication with the TX… it flies perfectly and then out of no where it just drops! No fpv gear, just battery, scisky, and then motors.
Old or new Lipo?
Sounds definitely like a power issue.
Tried to resolder the power leads?
It does it on old and new batteries… I have new batteries in the tx… I will try to resolder the power leads, but all soldering was done fairly well. Do you think i have a micro piece of solder between solder pads on a motor it could cause that? (I’ll double check for any connections that could be causing a short in the pads, but I really think I did a fairly good job on soldering those as wel)
Also, I fly this thing hard as a line of sight flyer, only 14500kv motors. Do you think it’s possible that I am over heating the scisky and it’s dropping out of the sky? I fly LOS pretty hard…
Edit: I think the power leads are soldering just fine, because it still has power to the FC when it drops of out the sky…
Another weird thing about this is when this happens I’ll try to connect to clean flight and it will say “failed communication within 10 seconds”, but then an hour later I’ll plug it in and it’ll start flying again and start working in cleanflight
I had one of the RX’s go bad on a Sciscky board. I replaced it with one of the micro PPM receivers from BG and its been flying ever since. I don’t remember what my lights were doing, but after 3 drops during flight, I was not able to bind again. At that point, I started surgery…
What size batteries are you using and what brand? Sounds like the FC is browning out although I have not heard much of the scisky doing that but if you are flying with a battery that is under 480mah it could cause that to happen. Does it happen when you punch the throttle or when you are just hovering? Last question. When this has happened have you checked the batteries voltage immediately after and is the battery and power lead hot? If it is choking the power somewhere or the battery is getting overworked there will be heat.