(Topic ID: 123403)

Stuck capacitor


By bigdaddy07

5 years ago



Topic Stats

  • 40 posts
  • 16 Pinsiders participating
  • Latest reply 5 years ago by viperrwk
  • Topic is favorited by 2 Pinsiders

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#1 5 years ago

I'm trying to remove a blown capacitor on my LOTR Whitestar board and it's stuck. I sucked the solder up that I could and clipped the leads down as far as possible. It wiggles just slightly. I don't want to damage the board. Anyone have any tips to safely remove this thing?

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#2 5 years ago

For capacitors I sometimes will lightly heat one side and pull the repeate the process capacitors seem to love to take the eyelet with them. Hopefully somebody has a better way.

#3 5 years ago

That's what I'm afraid of doing. I did what I typically don't do and stopped before I started getting to aggressive and screw something up. Hoping there's are trick to handling this.

#4 5 years ago

Try adding solder then sucking it out.

viperrwk

#5 5 years ago

Also, if they are snap in caps (the worst to pull off) -- try clipping the leads as close to board as possible. Rocking the caps as mentioned by coz6 works well but be careful not to overheat and pull pads off the board.

#6 5 years ago
Quoted from viperrwk:

Try adding solder then sucking it out.
viperrwk

^This. Try re-adding solder and suck it back out again. If still hung up, hold the solder iron on one of the leads to the point where any remaining solder will be liquified and then wiggle it. Then hit the other lead. Sometimes this might work if its just a tiny bit of solder, but if there sufficient solder there, it will harden back to it.
Can you see the leads on the other side or is the cap flat to the circuit board?

Also, if you do rip the upper pad, you can likely still salvage it as long as its not a multi-layered board which I don't think those are. If you don't take additional track off of the board, you could leave the leads long on the cap so that you can get a solder iron between it and the board, then clean the end of the track off to expose the copper and bridge a small piece of solder from the track to the capacitor lead. Then add solder to the backside of the board connections of course.
If you rip some track, you can add a piece of small gauge wire to make up the distance and solder both ends of it (track to cap lead). Tack the wire down to the board if necessary for stress relief.

Hope this helps.

#7 5 years ago

Those holes don't look completely cleaned out.

Resolder the holes with fresh solder.

Use a solder sucker.

-

If you totally can't get it unsoldered with the tools you have, then you can take SHARP diags and gently unroll the cap's outer aluminum foil can.

The inside is just a waxy roll (you would have a mess, if pins used oil filled caps, lol).

I once had a MIG welder that someone soldered in one of the caps (usually they have screw terminals) . No amount of heat would unsolder it, so it became a surgical procedure.

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#8 5 years ago

Thanks for the suggestions! I will give some of these a try as soon as I get a chance to work on this again. Hopefully I won't be drinking at the time.

#9 5 years ago

Use liquid flux on the leads let it soak down from the solder side then heat the legs.

If you have a Hakko use it to get up excess solder that is still remaining.

Flux is a miracle worker when it comes to removing large caps and rectifiers that you are trying to remove.

From the start its best to flux those leads then resolder then add flux again and desolder.

With the flux on the legs by heating them and keeping them heated (alternate legs with iron) you can wiggle the rectifier out. Should come out with little to no force at all. Be patient let the flux and heat do the work but don't let the components get too hot just enough to loosen them.

#10 5 years ago

You could also try Desoldering Braid.

#11 5 years ago

De-soldering braid / copper ground braid and the tip of the iron lightly pressed onto the "tabs" wicks up the solder. Don't over do the heat and use a decent temp controlled soldering iron to you do not roast the board or trace.

#12 5 years ago

If you go the braid route, apply some flux first. Makes life a whole lot easier.

#13 5 years ago

I'm trying the braid. What temp should I set the iron to?

#14 5 years ago

My wick isn't wicking too much. Arrrgg

#15 5 years ago

I use a Hakko FM2027 with a 1.6mm tip for caps like this. It slides over the leads so everything melts and when you hit the trigger it draws more vacuum than anything else I've used. You need compressed air to run it but it works like a champ: amazon.com link »

#16 5 years ago

Holy smokes! That's expensive. A new board would be cheaper.

#17 5 years ago

I might just be forced to send it to someone who has better tools and more experience.

#18 5 years ago
Quoted from bigdaddy07:

Holy smokes! That's expensive. A new board would be cheaper.

ebay.com link » S 993a 110v 90w Electric Vacuum Desoldering Pump Solder Sucker Gun

@ $108 this might be more up your alley.

#19 5 years ago

I was eyeballing this one. A little bit more, but reviews well.

amazon.com link »

#20 5 years ago
Quoted from bigdaddy07:

I was eyeballing this one. A little bit more, but reviews well.
amazon.com link »

I have the predecessor to that, the 474A+, and it's great. It's compatible with Hakko parts as well, it's a direct knock-off.

#21 5 years ago
Quoted from vid1900:

ebay.com link » S 993a 110v 90w Electric Vacuum Desoldering Pump Solder Sucker Gun
@ $108 this might be more up your alley.

that one looks a lot like this one but >1/2 the price..

http://www.tequipment.net/Hakko/FR-300/Desoldering-Equipment/

#23 5 years ago
Quoted from bigdaddy07:

I'm trying the braid. What temp should I set the iron to?

I set my Weller to 650 F

#24 5 years ago

Vid's idea is the best IMHO.

If you can't get it out, surgical removal down to the pins. This will allow you to desolder whatever is holding it in from the component side. The component doesn't matter - the board and traces do.

viperrwk

#25 5 years ago
Quoted from viperrwk:

If you can't get it out, surgical removal down to the pins. This will allow you to desolder whatever is holding it in from the component side.

This goes for anything you have to desolder. I always cut out the parts prior to desoldering, including ICs. I didn't do this for years, and lifted a lot of pad/traces. Nice sharp diagonal cutters are all you need, just gotta make sure you don't scratch the PCB while cutting or suck up the pins into your desoldering gun/station and clog it. You'll significantly lower the risk of damage to the PCB by cutting out components first, less heat needed to remove the component = less damage to the PCB. I'd rather cut out a PIA than try to remove it all at once. I know I can remove it at once with my desoldering gun, just isn't worth the added risk for a tiny bit more work. This method usually involves pulling out all the remaining pins with tweezers one by one afterward, but better than lifting a pad/trace.

#26 5 years ago

I use to nip all the legs of IC's until I used a Hakko 808 for removal.
A WORLD of difference....

No matter what you use on circuit boards you need a quality temp controlled iron or soldering station with enough watts to do the job.

#27 5 years ago
Quoted from cal50:

No matter what you use on circuit boards you need a quality temp controlled iron or soldering station with enough watts to do the job.

agreed

#28 5 years ago

I have a nice Hakko soldering station, but never ponied up for a high end desolder station. I've always had no problems removing the occasional transistor or rectifier with my cheap bulb desolderer. Never seen this coming. Removing these large capacitors seems impossible without a higher end station, if you don't want to destroy your board. Anyway, this time around I'm probably going to drop it off with Rob Anthony. I need him to give it a good look over anyway.

#29 5 years ago

Most components are cheap. Nowadays, I usually jus cut stuff out and resolder the legs after. Saves a whole lot of headache but can add $10-20 bucks to your repair depending on the component

#30 5 years ago

Just use wick, you mention it didn't pull too much solder, sometimes you have to add some to get it going

#31 5 years ago

If it is the "snap cap" type, the pins are curved, so when you inset it into the board it "snaps" in. They are harder to get out, hold the board on it's side, apply heat to the pins and keep switching to keep them hot. Gently wiggle the cap side to side, pin side to pin side(no pun intended) and keep heating between pins. It will wiggle out once they are nice and warm.

If you rip through hole plating out, you can use a "solder stitch", where you strip a small piece of stranded copper wire, slide several strands through the hole and fold them over to the ripped trace on both sides, then solder them together neatly in place to the traces. Clive outlined this I believe in one of his guides.

#32 5 years ago

So after reading over the suggestions again, I decided to take another crack at this using the deconstruction idea. Here are the pictures to chronicle the work.

The top side of the cap came off painlessly. Just like unraveling a can.

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#33 5 years ago

The wood bottom was a challenge. The posts were really dug in there. I tried cutting through it with a Dremel saw blade. Then I came to my senses and realized that that won't end well.

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#34 5 years ago

I ended up drilling them out slowly and carefully.

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#35 5 years ago

Heating up those remaining tabs with the soldering iron and they wiggled out nicely.

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#36 5 years ago

Installed and working again. Thanks for everyone suggestions here, they are very much appreciated. You guys are the best!

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#37 5 years ago
Quoted from bigdaddy07:

Thanks for everyone suggestions here, they are very much appreciated. You guys are the best!

Yes, yes we all are.

#38 5 years ago

Nice fix!

A quick question though; heating up the posts directly from the top of the board did transfer enough heat to free it?

#39 5 years ago
Quoted from vid1900:

A quick question though; heating up the posts directly from the top of the board did transfer enough heat to free it?

I had to put the heat on the ring to loosen them up. I tried the post, but wasn't giving from there. I realize my wording sounded like I heated the posts up.

#40 5 years ago

Nicely done. And thanks for the photo documentation.

As Ed said it was a snap cap so the leads were likely holding it in.

viperrwk

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