Wow. That's amazing. I haven't had the need to rework a BGA, but now I'm inspired to find my own balls to play with (couldn't resist it). Nice vid!
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Replying to @freaklabs @bunniestudios
I should probably clarify. I've never needed to rework a BGA because my lazy butt would just wait the two weeks and respin the board. Never knew there was a technique to soldering jumper wires underneath a CSP.
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Replying to @freaklabs
It's amazing what you can learn on the streets of Shenzhen
Sometimes I peek into the SMD repair shops and glean a technique or two. Some might even say I stole/copied their trade secrets.
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Replying to @bunniestudios @freaklabs
I didn’t know you could get UV soldermask. Off to look for some now! This is also why I miss going to Shenzhen.
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Replying to @N1FIY @freaklabs
This is the tube I'm using in case it helps.
#todayilearned it also partially cures with heat.pic.twitter.com/DAOaEULHhw
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Temp definitely impacts UV cure speed too. I’ve noticed much much longer times when in a cold (40-50F) garage. Nice rework! What’s the reason for wire next to & not under? I think there may be some tweaks to simplify the positioning part of this.
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Wire under leaves no space for the solder, so you either get the ball pushing up the CSP causing disconnects, or excess solder shorting to neighboring balls. Putting it next to the ball causes the molten solder to wick onto the wire, away from neighbors & preserving planarity...
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Replying to @bunniestudios @_MG_ and
So you couldn’t know if the wire is attached until after placing the CSP, right?
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That is correct. The wire directly connects to the CSP when you place it. There is no connection from the wire to the board on the CSP side.
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Replying to @bunniestudios @_MG_ and
I’m always get a mess trying to attach those wires, especially have difficulties exposing the end
Got any tip for me? It looks like you didn’t do anything here, perhaps the heat from the reflow melted the isolating layer?1 reply 0 retweets 0 likes
You remove the enamel from the magnet wire by melting fresh solder onto it. The key is, you need to put fresh solder on so the flux core is very active and attacks the enamel aggressively before it burns off.
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Replying to @bunniestudios @raziel_e and
Check out Temco Soderon. I he enamel melts off at 155C and turns into a pseudo flux.
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