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Power leads to power board connection came loose

Discussion in 'Cinestar 8' started by Cris Olariu, Jun 15, 2013.

  1. Cris Olariu

    Cris Olariu Member

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    So last weekend I went ahead and switched to EC5 connectors on all the batteries and the power leads to the power dist board on my CS8. Today as I was cleaning up under the hood I noticed that the negative part of the board where the lead connects to came loose (as in unglued) from the board. It is still very well connected to the power lead and it seems well connected to the rest of the board as well. I'm assuming it came off during the soldering and I just didn't notice it till now. How should I go about fixing it? Or do I need to get another board and start fresh?
    Thank you!
     
  2. Cris Olariu

    Cris Olariu Member

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    Here's a quick picture of the thing that came loose...

    power dist board connector.png
     
  3. Gary Haynes

    Gary Haynes Administrator
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    Cris that's not a real good sign. When a pad lifts off like that it is usually due to application of too much heat. Not sure that there is a way to fix it. Maybe others will know. But through normal wear and vibrations there is good chance the the copper will separate from the underlying PCB which would lead to a power failure.

    Maybe supply photos of the damage for more input from the members?
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    One possibility (that I would use if the above happened to my PDB), is to epoxy the copper back to the board -- and possibly put some additional epoxy around the entire pad assembly to prevent the wires torquing it off again. Downside, of course, is that it's epoxy so if you ever have a problem that requires resoldering the leads, well.....

    Andy.
     
  5. Cris Olariu

    Cris Olariu Member

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    Alright guys,
    Sorry it took so long before posting the pictures from the actual PDB. Before I even wrote on this forum about the problem, I had come with the "genius" idea of covering up the pad assembly with some Brush-On Electrical Tape and let it sit like that. Now that I'm back home, I am attaching a picture of it, with the black Brush-on Electrical Tape on, as I wasn't smart enough to take one prior to the application. It seems to hold right now, and I don't want to pry it up just for the picture. Unless of course you guys think that's a horrible idea, in which case I'll clean it up and and take the picture (gotta of course figure out how to do the cleaning first), and possibly follow Andy's idea with the epoxy.
    Thoughts?
     

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  6. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    The paint on insulation is goop for insulation, but I'm worried that there is no structural strength to it -- and with the vibration on the hub, the copper will fatigue and your bird with drop from the sky. You could *still* apply epoxy of the top of what you have now to form a structural blob of epoxy.

    Andy.
     
  7. Cris Olariu

    Cris Olariu Member

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    Andy, thank you for your response. I'll see if I can clean up the paint-on tape and use epoxy. If not, I'll just make a "blob of epoxy". :)
    So you think that once I do that I won't be able to re-solder the leads if I need to, huh? I mean, I hope I won't have to do that too often anyway, now that I switched to EC5 connectors.
    Any brand you recommend? I usually like Loctite...
     
  8. Gary Haynes

    Gary Haynes Administrator
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    Cris it will be a bit of a pain but I would buy a new PDB, remove all of the BL's, maybe buy new CAP' because the are cheap and it would be easier to reinstall the BL's. I just wouldn't trust the old board.
     
  9. Cris Olariu

    Cris Olariu Member

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    Ugh Gary... I was afraid I'd have to do that. What do you mean by CAP?
     
  10. Gary Haynes

    Gary Haynes Administrator
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    The round capacitors, two per BL. I'll see if I can find some video links on how to do them. I thing QC had something.
     
  11. Cris Olariu

    Cris Olariu Member

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    You don't think I could recycle the existing ones? Also, I prolly need to get another molex connector, right? Looking at the board, I'd think that's the most difficult one to attach to the board...
    I'll make sure to call QC support tomorrow morning before placing the order to make sure I get all the parts needed, but any tips you have are more than welcome.
    Thank you.
     
  12. Dave King

    Dave King Well-Known Member

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    Cris

    I just had a major crash where my copter fell out of the sky and totalled about 85% of everything. Mine was not power related but essentially the copter can just fall out of the sky like mine did if that tab breaks off. I have had mixed results with epoxy as well when installing security brackets to equpment. I"ve tried about 10 different epoxy products over the past 12 years and I always thoroughly clean the surface before using. Again I have seen mixed results. From my experiences it either bonds like steel or it can be brittle and not hold well. I"ve even had the same results with JB weld.

    You can buy another used board from Quadrocopter for $600 http://www.quadrocopter.com/Used-Okto-XL-Power-Distribution-Board-Pre-soldered_p_876.html. They are bench tested and work. I"m not saying what Andy is suggesting won't work as he has good ideas but if there's a 1% chance what you do will come loose from vibration I wouldn't chance it when you can get another board for $600 and not worry about your $10K plus investment. Plus you could use your existing PDB for backup BL spares.

    Take it from my personal experience you don't want to have a crash where you have to take every single piece apart, inspect it, and replace the majority of your bird because of a crash. Not only can your CS8 fall out of the sky, it could seriously hurt someone in the process.
     
  13. Gary Haynes

    Gary Haynes Administrator
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    You may be able to recycle the Cap's but once the leads have been trimmed off you may find that there isn't enough length left to put them on a new PDB board. And with new Cap's, after you trim them you use the left over leads for the C/D connections on the other end of the BL. The board is about $55 and the large Cap's are just over $2.

    Maybe QC could do the rebuild for you?
     
  14. Adam Paugh

    Adam Paugh Distributor

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    hr
    Hello Chris,

    Here is a video we did for the assembly of the ESCs into the PDR:
    !
    You will need to remove the ESCs from the existing PDR first.

    Greetings,
    Adam
     
  15. Cris Olariu

    Cris Olariu Member

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    Alright... It does indeed look like a big job to reconnect all the BLs to the PDB. But I think that following the video that Adam was kind enough to share earlier, I can pull it off. So the plan is to order a new PDB, the CAPs, and the Molex connector from QC today, hopefully get them by the weekend, then take my time over the weekend to get it done.
    I did also consider Dave's idea of getting one of the used boards from QC (even added it to the cart). But after seeing the video, I think I'll get the hang of it pretty fast. It'll definitely be a good experience. So here we go, placing the order! I'll update before and when I'm finished.
    Thank you guys!
     
  16. Dave King

    Dave King Well-Known Member

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    HI Cris

    Glad to here that you are not trying to repair your board. Be prepared for a titious job unsoldering the BL boards from your existing board. I've been soldering and repair electornic components for 20 years and I found working with the MK boards to be very difficult to remove solder. They do not like a lot of heat and you can get into trouble fast if you apply too much heat too long. For the BL's I found a solder sucker is best to remove the solder from the cap pads but I know they don't recommend a solder sucker for these boards. Solder wick is definetely more time consuming.

    One other piece of advice make sure you get a good magnifying glass that has a good light so you can inspect each BL from any solder spatter that you might get. It's very easy to get a tiny piece of solder on the smallest spot. I used isophrol alcohol and a very soft tooth brush and went over everything after I was done soldering. It's also a good time to solder in any power connections you need for FPV or anything else you want to use. I use JST connections so its easy to plug in and unplug if you need to remove the board. Good luck.
     
  17. Cris Olariu

    Cris Olariu Member

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    Dave:
    Solder wick is what I tend to use, but indeed time consuming and very frustrating at times. So what temperature do you normally have your solder iron on for this type a job? I obviously applied too much heat when soldering the leads on that it unglued the pad, so I don't wanna make the same mistake. I'd rather take the time, then do it fast (apply too much heat) and ruin something else.
     
  18. Dave King

    Dave King Well-Known Member

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    I have an adjustable weller station and normally set the temp around 650. If I am doing surface mount components like the extension PCB board I will set it to 775. When I'm using a solder sucker I found the process of cleaning the tip and adding a little bit of solder before I hit the pad works better than hitting it with just a clean tip. Choice of solder wick is extremely important.
     
  19. Gary Haynes

    Gary Haynes Administrator
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    Cris what are you using as a soldering station?
     
  20. Cris Olariu

    Cris Olariu Member

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