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Soldering SMD electrolytic capacitors

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Sarcasmo

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Anyone know anything about surface mounting v-chip aluminum electrolytic capacitors to PCB? I have to replace 11 of them in a projection t.v. and I don't know how to affix them to the board. Solder paste? Are reflow techniques possible with temperature-sensitive components on the board?

The plastic bases are throwing me off because the metal cap tabs are located underneath. I don't know how to keep solder molten on both tabs simultaneously long enough to drop the cap onto the board where it needs to go.
 

We use something similar here at work. Our caps have a small tap the extends beyond the plastic. It is not much but is sufficient to get an iron on.

I use two irons at the same time to remove the cap by heating both pads at the same time. Then I clean the pads with solder wick to remove all solder. Next using only one iron, I place the cap on the board and heat the tiny tab extending beyond the plastic. I feed solder into the pad until well wetted. Repeat on the other side.

P.S. The ones we use have very high temp plastic on the bases, so they can take the heat of the iron.
 

Interesting. I'm assuming you are very careful not to bridge the two tabs, since they're polarized caps? That's my concern. I noticed after I read your post that the tabs do stick out very minimally from under the plastic. If soldering the ends of those will be sufficient then fantastic. I just don't want to put too much metal between the two of them, and not notice until it pops later.
 

I have never had it form a bridge under the capacitor. The solder mask between the pads keep the solder from flowing between them. If you don't mind wasting some solder wick, you can prove this on your own boards. Remove the capacitor and then heat the bare pad and start flooding it with molden solder. It will bead up on top of the pad, but will not flow across the solder mask to the adjacent pad. It has to do with the high surface tension of molden solder.

With the small exposed pad you can get enough heat to fully solder flow the lead. The solder will flow under the part and solder down the entire lead.
 

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