5-1 board issue

[Liduno]

I crashed really hard into a steel trailer.

Right after I crashed it, I lifted off and I could hear the main motor glitching on and off and then the blue led went out.

I noticed I boogered a servo gear and the servo was sticking so I changed the gear but couldn't seem to get the board to initialize unless I tapped on the servo gear..

I checked for loose connections and cleaned the potentiometers on both servos with no improvement, I changed the servo thinking maybe the servo motor was bad or shorting out internally.

After changing the servo my bench test went perfect and every thing worked, but when I installed the board back on the heli it flew for a second or two making the same motor glitch as before and then the led went out. Thinking it might be a motor issue I disconnected the tail and main motor, both servos worked for a few seconds then the led went out again..

If I tap on the servo gear the led will come back on solid but soon goes out again.

I looked and looked for a break or crack on the board with a magnifying glass but I couldn't see any thing.

Any ideas?

[wulfrun]

Certainly sounds like a crack or bad connection somewhere on the board. If you can't find it under a magnifying glass, you might be in need of a board or board repair service. Bad news, I guess. Moral - don't fly near trailers.

[Liduno]

Yeah I was thinking a new board too, I was just hoping some one had a different idea.

[Liduno]

. .

[Mega Stumbler]

Liduno, I recieved your PM about this problem. I didn't forget about you. I have just been taking my time and thinking hard on what the cause may be. I don't like to guess. I like to make sure my theory is sound and has a good chance of being the main issue. I'll come up with something.

[Liduno]

Originally Posted by Mega Stumbler

Liduno, I recieved your PM about this problem. I didn't forget about you. I have just been taking my time and thinking hard on what the cause may be. I don't like to guess. I like to make sure my theory is sound and has a good chance of being the main issue. I'll come up with something.

Thank you sir Im going to take a look at it again with the magnifying glass to see if I can see a crack or some thing.

[Liduno]

Holy crap I think these old eyes of mine found it, I know nothing about this kind of thing so Im not sure what the component is but it looks as though I knock a solder joint loose on a fet.

It's just below the tail motor plug but on the opposite side of the board, It says ADGV-1v and it has 3 prongs soldered to the board, well 2 now..lol

I suspected it was a connection issue because the board would sometimes work if I tapped on the servo gear.

Mega Stumbler, do you think this could cause the symptoms I described?

[Liduno]

That's definitely the problem. If I hold pressure on the component the board initializes and the servos work as they should..

Now the question is with my lack of soldering skills can I solder this thing back on with out cooking any thing..lol

[wulfrun]

Glad you've spotted it, it'll be one of the motor FETs from what you describe. You probably have lead-free solder to thank for the issue, it's rubbish compared to the old stuff (ask yourself why the military and medical people are exempt from the ban).

When re-soldering, you probably won't have much trouble re-flowing the solder. Just use a very fine-tipped iron and be very quick about it. Those FETs are so small they will heat up very quickly and they're easily destroyed. If it doesn't re-flow after a fraction of a second, wait a minute for the area to cool completely before trying again. Good luck!

[Mega Stumbler]

That's good advise wulfrun. But you forgot the flux. Please put some flux on the joint before you heat it. It can really be the difference between a great repair and a disaster.

Good find on the cracked leg.

Good luck.

Sent from my DROIDX using Tapatalk

[Liduno]

I gave it the old college try last night, I have pretty big weller soldering gun but I have a few different tips so I figured I could getter done.

I used flux, tinned and cleaned the tip but I had a little bit of a hard time getting the solder to flow.

Finally seemed to have it all soldered up, but when I fired up the board on the bench, it works perfect for about 5 seconds at a time, then the led goes out..

I was frustrated at this point so I put the board away.

I have a new found respect for people like you that can fix these things..lol

[wulfrun]

Originally Posted by Mega Stumbler

That's good advise wulfrun. But you forgot the flux. Please put some flux on the joint before you heat it. It can really be the difference between a great repair and a disaster.

I would not necessarily use flux on a broken joint. If the solder was parted mechanically it should just re-flow. However, there's not any harm in using some. Personally, I'd add a bit more solder (cored) to make a better joint than the one that failed.

[wulfrun]

Originally Posted by Liduno

I gave it the old college try last night, I have pretty big weller soldering gun but I have a few different tips so I figured I could getter done.

I used flux, tinned and cleaned the tip but I had a little bit of a hard time getting the solder to flow.

Finally seemed to have it all soldered up, but when I fired up the board on the bench, it works perfect for about 5 seconds at a time, then the led goes out..

I was frustrated at this point so I put the board away.

I have a new found respect for people like you that can fix these things..lol

Get the magnifying glass out again and make sure you really have re-made the joint. If you're sure, how about others needing treatment?

[Liduno]

Originally Posted by wulfrun

Get the magnifying glass out again and make sure you really have re-made the joint. If you're sure, how about others needing treatment?

I picked at all 3 joints with a sewing needle to see if they were secure, and I looked all over the board for any obvious damage but couldnt find any thing.

I have reached the end of my capability with this board..lol I'll just send it to Mega Stumbler if he thinks it's salvageable but if not I guess I at least have spare servos.

[hydro_pyro]

Here's some more info here:

https://www.helifreak.com/showthread.php?t=203418

[Liduno]

Originally Posted by hydro_pyro

Here's some more info here:

https://www.helifreak.com/showthread.php?t=203418

I just subscrided to that thread this morning before I even clicked on this thread..lol