Bad OST caps on an e-machine MCP61SM-GM

[c_hegge]

Re: Bad OST caps on an e-machine MCP61SM-GM

^
Alcohol won't be a problem. I've even used 99% Isopropyl without incident.

[Th3_uN1Qu3]

Re: Bad OST caps on an e-machine MCP61SM-GM

Isopropyl is actually the preffered type to use on circuit boards. Rubbing alcohol leaves white residue behind.

How long is the broken lead? If it's got a bit of length left you should be able to remove it by heating the joint with your iron while pulling it with tweezers.

[momaka]

Re: Bad OST caps on an e-machine MCP61SM-GM

The flux I have though isn't no-clean.

Make sure to clean it then.

I still cannot get the broken lead out though. I'm thinking of trying to maybe drill it?

You're very likely to damage the board this way.

As others stated isopropyl alcohol works great for cleaning flux.

[Spork Schivago]

Re: Bad OST caps on an e-machine MCP61SM-GM

Sorry guys, I didn't realize we was on page two of this post. The isopropyl is working great. I thought it'd eat threw the board but it seems to be doing the trick. I'm using a 70% solution.

Grabbing the broken lead with a pair of tweezers is a no go though. I've tried and I just cannot get a good grip. I can take pictures if you want. I was thinking of perhaps trying to push it through again from the other side while heating it.

With one of the capacitors I removed, the solder stayed in the holes. I've tried adding solder and removing it to get it out but it doesn't seem to help. Any suggestions there? I was thinking of taking one of the good caps and heating the lead up while holding it on the solder in the whole but was afraid the temperature of the iron would damage it before it melts. I'm currently at 842F.

Also, the flux and higher temperature was the solution to removing these things it seems. I've tried without the flux on one just to see and sure enough, it wouldn't come out. I add the flux and viola! I can walk them out every time.

[momaka]

Re: Bad OST caps on an e-machine MCP61SM-GM

Grabbing the broken lead with a pair of tweezers is a no go though. I've tried and I just cannot get a good grip.

I had to do this only twice on two different boards and I did it in 2 different methods.
With the 1st method I just melted the solder around the broken lead with the iron, then grabbed it with a sharp pair of cutters and then pulled it out (note I pulled the lead out from the solder side, not it's normal side).
With the second method, I used a thick needle, then pushed the lead out (from the components side towards the solder side again) after I heated it with the iron for a few seconds.

Also, the flux and higher temperature was the solution to removing these things it seems. I've tried without the flux on one just to see and sure enough, it wouldn't come out. I add the flux and viola! I can walk them out every time.

Yup, like I said, once you use flux you will never go back to soldering without it .

[Th3_uN1Qu3]

Re: Bad OST caps on an e-machine MCP61SM-GM

With one of the capacitors I removed, the solder stayed in the holes. I've tried adding solder and removing it to get it out but it doesn't seem to help. Any suggestions there?

I don't even bother to remove the solder on multilayer boards like PC motherboards, too much of a pain in the ass. Just make sure the leads of the new cap are aligned with the holes, heat the two pads alternately with your iron, while slowly pushing on the new cap in one direction and then in the other.

You'll get the hang of it quickly, the only tricky bit is keeping the new cap aligned while pushing on it, sometimes it tends to wander away before the leads push thru the molten solder.

[severach]

Re: Bad OST caps on an e-machine MCP61SM-GM

I used to walk capacitors back in that way but the method is slow and it doesn't work well when the capacitor is between PCI slots. Walking out was hard enough. Walked in leads may not solder well in the vias and the constant flexing makes them come out like earwig tail pincers. All low quality work and done enough times results in bad solders. Flux is necessary for repeatable high quality work.

After clearing the holes with a straight sided object (no point, no taper) I trim and flux the leads. This lays flux all through the via and when the heat is applied the solder leaps from the walls of the via onto the lead providing the same strength and quality as the original wave soldering. The better quality the original solder the more like factory the hand soldering looks.

Flux is easily removed with a cotton swab and any alcohol or carb cleaner that doesn't have a smell too offensive for indoor use. Adding and removing flux a few minutes later may seem like a waste of time but it most certainly is not. Flux makes the impossible possible.

Flux on the joint. Solder on the iron.