Help needed with the main board

[georgero]

If anyone can tell me what causes these fuses to burn as soon I turn on the drone it will be much appreciated, First I was thinking the motor is in the short circuit but the fuses burn even without the motor attached.
The drone tilts on landing and hit the ground with the propeller and then bounced back and I stopped. I started again and I have a wired series of beepings and I was sure it has to be something with that motor. I opened and those fuses are burned. I make some jumpers


and as soon I turn it on blew again. Please let me know if you know anything about it. Thanks.

 

[Steve Carr]

It's hard to see in your photo but there appears to be burnt spot on one of the components:

 

[WTFDproject]

I don't know H920. But I can make some suggestions based on other models.

The suspect component appears to be one of the motor mosfets. There should be another set of three just like them on the other side of the board. One set is power, the other is ground. There are two per motor lead, and three pairs per motor. The six work together in an open/close pattern to provide a sort of variable AC current to the motors. When one of a pair fails closed, they are both blown when the other closes and creates a direct short circuit. In other words, if one is damaged, they are both damaged. But only one will normally APPEAR damaged. The mosfet numbers should be visible with a good light and a magnifying glass. Most are available on eBay using the mosfet number. Most models had a different mosfet on top than on bottom, so be sure to check numbers on both sides of the board.

That's the easy part. The bad part is the jumper you put across the fuse. Whatever the fuse was protecting probably got a pretty good hit before the jumper blew. If the fuse only provides main motor power, you may be OK. If they feed other things, you may have problems.

I would at least remove the two damaged mosfets, and see if the board will still power up. It will not initialize, of course, but if it does not power up at all (or blows again), it will take someone much more familiar with H920 than I am to make any meaningful recommendations.

 

[georgero]

Thanks for the heads up guys I found only one mofset was bad and I ordered from digikey. After I removed the fuses worked as it should.Once again thanks.