Mikrokopter MK BL component question

[Bartman]

If you look at the top of a Mikrokopter BL 2.0 with the mounting hole towards you, what is the little dark tan colored brick shaped component that is four components to the right from the hole?
View attachment 794

how do they work and what purpose do they serve? circuit protection like a fuse maybe?

thanks
bart

 

[Droider]

I think its a jumper bart.. Why has it fallen off?

 

[MombasaFlash]

i think its a jumper bart.. Why has it fallen off?

lol

 

[Bartman]

I think its a jumper bart.. Why has it fallen off?

was that a joke and I missed it?? it didn't exactly fall off, one of them blew off in a big spark and audible pop and on the other two BL's they kinda cracked open on one end with a little burned area left behind for good measure. I'm not sure if I did something to cause the pyrotechnics or if the board had issues but it's back where it came from and I'm awaiting a verdict. If I end up paying for replacement BL's I'd like to get the burned ones and try to fix them (provided I can get magnifying gear strong enough to allow my bat eyes to see what I'm doing).
Thanks,
Bart

 

[Crash]

I don't have any of those ESCs to check. Do you have a macro photo of the bad board and a good board?

Is it possible that you sent reverse polarity into the boards?

 

[Droider]

No Joke! I had one fall off while I was adding the cap's.. this is what fell off mine

 

[MombasaFlash]

And this is what fell off mine ...

View attachment 793

 

[MombasaFlash]

How come you've got a nice big, fat picture on your post and I only have a piddly one that has to be enlarged? (hope we don't get accused of being off-subject again ).

 

[Bartman]

updated first post with a picture......any electronics experts out there?

i'm trying to assemble some understanding of why I keep blowing BL's. if it isn't my fault i need to be able to explain why.

yes i should be sleeping but i took a decongestant before going to bed and it's got me wired!

thanks,
bart

 

[Bartman]

capacitors maybe?

http://en.wikipedia.org/wiki/File:Photo-SMDcapacitors.jpg

 

[MombasaFlash]

If you look at the pic that I posted it shows component labels printed on the board. All those that look like yours are labelled C1, C2, C3 etc. So presumably your little tan bricks are capacitors. Can't be any more help with your BL-blowing problem though, sorry.

 

[Crash]

As I understand it, most of the caps on the BL-Ctrls are for filtering power fluctuations. I can't find any parts diagram for these new boards to determine exactly what part number is in each location.

I've had my doubts about the manufacturing process with these for a year. I don't think I would trust one until I reflowed the entire board. It's hard to say though because I still haven't seen a decent picture to tell if the solder was fully melted.

 

[Bartman]

View attachment 795

Crash,
I sent you two photos last night via a web delivery service, check your spam folder. Here's the schematic from the MK wiki.....

it looks like there's a capacitor wherever full battery voltage (VCC) comes into a particular circuit grouping. i'd like to mark-up a BL photo with red dots so someone with a multimeter could check for both continuity and voltage wherever the VCC's are on the diagram. Maybe continuity only would be sufficient.

Thanks
Bart

 

[Crash]

I have all the schematics. The problem is matching the schematic to the board without silkscreening or a graphic that shows placement.

Something like the pic below would be helpful. MK may have put one out but darn if I can find it on the wiki.