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cowboysir
2008.07.12, 06:03 PM
Hey!

Long story short, I must've mixed up my motors and mounted a hot motor on a 3010 board...it got fried so bad it melted the chassis a bit.:eek:

So anyhow, what are your suggestions on saving this bad boy?

http://i13.photobucket.com/albums/a258/CowboySiR/fetproblem002.jpg
http://i13.photobucket.com/albums/a258/CowboySiR/fetproblem001.jpg

As you can see, the trace that leads to the motor tab is lifting and exposed. The one side is worse than the other so...

It's been suggested to me on another site that i might direct solder motor wires to the fets...i like the idea but i wanted to get a good idea of how to make sure the fet stays in place.

On another possible fix, is it possible to CA glue the trace back to the board and would it stay in place after soldering new fets on top?

Thanks in advance for any advice you can share.;)

imxlr8ed
2008.07.14, 12:09 AM
Doesn't matter if the rear pads are lifted, you can just run a bead of solder to the motor pad. Also, you can just connect all of the rear feet with solder. The forward ones are where a lifted pad can spell disaster.

I just did one for one of our crew here... it lifted the far outboard forward pad which leads under the fet. I basically took one strand of motor wire and made the connection to the fet foot. You have to gently scrape away the top "green" of the board to expose the routing inside. Once it got that exposed, I ran some fresh solder on it until it stayed in position. then I wire strand onto the board and held it into position as connected it to the new solder joint. I bent the wire strand to the old pad location and trimmed off the excess.

When I put the fet on in conditions like this, I usually save this new connection for the very last so as not to move it out of place or disconnect it. If the new connection area is not under the fet, I usually install the fet first in the usual way and then jump it to the new connection point soldering it to the fet foot first.

Yes... it's tedious, yes... it's tough to do... but it does work and it's worth the effort to save a board. Just be careful removing those forward feet on that inboard fet, don't force it free, let the heat do the work and watch so the iron itself doesn't catch on the pads and break them off when you're moving it around or applying pressure.

cowboysir
2008.07.14, 08:45 AM
thanks imx...in some other discussions we came to pretty much that same conclusion.

i'm going to have to get a better soldering tip and start practicing...i believe this'll be a fun way to save the board and improve my skills for our club here in Whistler. a buddy of mine who buys everything (not joking) has a schwack of 8962's I can use for practice.

Wish me luck.

imxlr8ed
2008.07.14, 09:14 AM
It's tough to even describe some of the little intricacies, and every case is always different. You're absolutely right though... you won't really learn it until you try!

Things I consider very needed items when doing this kind of work:

Very clean and pointy soldering iron

Fresh solder

Good lighting (better when it's from 2 separate sources... led headlamps work great!)

Some type of clamp or holder with a weighted base

Tweezers

Xacto knife (new blade)


Best of luck!