tips to not botch a SMD cap kit

Hi guys,

Recently I've been getting into soldering and I've done some cap replacements to some great success, but these were point to point not SMD.

So I got a super famicom from japan recently and its sound wasn't the greatest, then I figured it needed some new caps, and after reading into it on Console5's wiki it seemed easy.

Or so I thought.

Things were going well with the cap kit, until I started lifting pads all because I used a solder sucker when I really shouldn't in retrospect, at least I think that's what caused everything to fall apart (and the result was no sound after that disaster).

So I ask, so I don't repeat this mistake (since I'm planning on doing a cap kit to my genesis real soon): what do I do to not repeat this mistake?

To those wondering what soldering iron I was using: its a Weller WTCPT.

 

I guess the part where you caused damage is the removal of the old SMD caps.
Text books will likely tell you to use a hot air station but in my opinion, the safest, easiest and fasted is to grab the SMD cap with long nose pliers and gently wiggle it until until it breaks off, which happens very quickly and never seems to damage the pads.
You then only have to remove the remnants of the the legs with a touch of your soldering iron.

I have done numerous motherboards with SMD caps using this method and never had any issue.

 

Does anyone use soldering tweezers for this kind of work? I don't do SMD work often, but I like the idea of having the tools to make my life easier. They look cool in the pictures, but I've never had one in my hands.

I kicked myself for not buying a Hakko desoldering gun sooner, and I'm wondering if soldering tweezers are something of that nature.

 

I got a pair of soldering tweezers gem the 100 yen shop. They're handy, since they grip by themselves. If you're ab amateur, doing the bendy dance like maxwar suggested would probably be easiest. And if you're using a iron that isn't temperature controlled, it might be a good idea to hold off untill you buy one that is temperature controlled. It's always a bit risky soldering delicate components with a iron that's going to get hotter and hotter.

 

I use soldering tweezers (jbc nano) on a regular basis and it's especially great to remove smd stuff, totally the perfect tool for it. It can be really expensive though.

You might want to try using soldering wick to try to suck off the solder instead of a pump.

A tip for soldering smd: pre-solder a single pad and footprint pad, place the chip and solder that single connection and set the chip in place correctly, then solder the rest of the pins one by one or by dragging solder to them. A typical mistake is to pre-solder all the footprint pads and get a skewed component because you can't melt all the pins at the same time.

FG

 

I use MaxWar's recommendation of using pliers for the SMD caps on the SNES. I then use my soldering iron and a bit of solder to take care of the pads, using a braid to take care of the excess. Clip the legs to an acceptable length, like one or two cm from the base of the capacitor. Solder one leg, and then the other, one at a time.

 

This could work too (I think thats what family guy is using similar)

 

If you're cheap 2 soldering irons will work fine. One on each end of the SMD then lift. It's the way I was taught (in a factory no less) and still the way I do it. Bought a cheap second iron for that purpose alone. If the pads need cleaning afterwards hit them with flux paste and braid then clean.

 

In my opinion it is useless to try to desolder old SMD electrolytic caps. It will take more time and you will have to deal with the noxious fumes of burning electrolyte. Not to mention de said old crusty electrolyte will prevent de soldering tweezers from making a proper contact to the solder.
Wiggling the old cap until it breaks is fast and safe.

I do not have the soldering tweezer but I have a hot air station and a desoldering gun. Someone who removes a lot of SMD ceramic caps and resistor might like the tweezers but I have a technique with flux and wick to remove them in seconds so I do not feel like i need those tweezers since I only occasionally need to remove such components.

 

Soldering tweezers are clearly a luxury, but they're really handy to have to desolder 0201 footprints without lifting traces. Though I guess using two irons would work fine, same goes for hot air station. I use a smaller pair Leham, but it's the same concept. I never desoldered smd electrolytic capacitors though.

 

Here is how I desolder SMD ceramics and resistors and other similar component.

1. I put a drop of flux on the component.
2. I apply desoldering braid on the component. ( this actually works better if there is a bit of solder already in the braid. )
3. I heat the braid with the flat of my iron until the solder under melts
4. With a light side motion I lift the braid up and the component is stuck on the braid.
5. With a flick of the iron while everything is still hot I take the SMD component off the braid.

This is much faster and easier than it sounds. Likely not as fast as using the soldering tweezers but likely easier than using two irons.

 

SMD tweezers are over rated. I rarely ever use mine. Using 2 irons is even more crazy.

SMD aluminum caps (turn them and they come away inside the cap) - remove the legs with braid and some fresh solder.

SMD passives like ceramic caps and resistors, hot air or just a blob of solder if you arent bother about keeping it.