Yet another via repair tutorial...

Post by **Eric D** » Fri Jan 22, 2010 10:23 am

Since I am getting more and more amps where you guys are damaging vias, I made this tutorial to help. It is just one of many ways you can fix these things...

http://www.soundbuggy.com/Eric/Car%20Au ... index.html

Please give me any feedback you have or suggestions to improve it.

bruther · Post by **bruther** » Fri Jan 22, 2010 10:50 am

quick question, when desoldering, do you use adesoldering iron or just the braided wick? If you use a desoldering iron, any recommendations?

Post by **Eric D** » Fri Jan 22, 2010 11:20 am

I use a desoldering pump, and braided wick. Typically the pump works best for me and then I clean up the area with the wick. It really depends on your personal preference.

I considered getting a real desoldering iron some day, but for now I can't justify the cost.

scottn29 · Post by **scottn29** » Fri Jan 22, 2010 12:37 pm

Nice write up Eric, maybe sometime you can do one to show your method of removal of the rail caps like we talked about.

mudder · Post by **mudder** » Sat Jan 23, 2010 6:31 am

Very helpful, thanks.

k2f-gold · Post by **k2f-gold** » Sat Jan 23, 2010 7:16 am

hi eric, just a quick question. i'm a newbie in this electronics repair... but i'm worried that my desoldering will do much damage by overheating too long on the board. will this cause any problems? and how can I make sure no overheatin occurs.... I think this is more common when i'm trying to extract those solders that's inside the via.

my desoldering is done using a small blue hand suction pump.

very good info from you link... tq.

Post by **Eric D** » Sat Jan 23, 2010 8:15 am

To remove most things I actually ADD solder to the connection. When you add solder, there is more mass to retain heat and keep it flowing longer for you to pull the item out. You then go back and use a solder pump and wick to remove the solder left over after the part has been extracted. To remove these big rail caps I add quite a bit of solder to the connections and jump back and forth with the iron keeping both hot. I many cases the item will fall out on its own doing this (these caps snap in so they never fall out though).

nico boom · Post by **nico boom** » Sat Jan 23, 2010 8:29 am

Didn't know you already posted this method earlier Eric;

Obviously we agree about how-to-do-this....

http://phoenixphorum.com/how-to-repair- ... 11910.html

Post by **Eric D** » Sat Jan 23, 2010 3:27 pm

I knew you posted a method, but I forgot what it was. Mine is pretty much the exact same thing as yours, although I think folding the wick makes it far easier to get into the hole.

nico boom · Post by **nico boom** » Sat Jan 23, 2010 10:30 pm

Eric D wrote:I knew you posted a method, but I forgot what it was. Mine is pretty much the exact same thing as yours, although I think folding the wick makes it far easier to get into the hole.

Therefore I place a awl in the hole; the awl presses the wick against the outside of the hole,creating a perfect round hole to easily insert the leads of the cap.
Also the awl absorbs the heat going into the hidden part of the wick during soldering, preventing solder flowing through the wick into the hole and clogging it.
Making it a better way to do it IMO, especially for those who do not have a temp. regulated soldering-iron.

Post by **Eric D** » Sun Jan 24, 2010 8:40 am

You probably should have explained the awl in your writeup, as I had no idea of that until you just mentioned it.

Also, your technique would work perfect for the input caps with round leads, but in the case of the snap in caps, you don't want a round hole. With them you want the wick to be out of the way of the snap in lead which is flat, but completely touches two sides of the hole.

If there is any wick in the way when you put a snap in cap in place it will further damage the fiberglass around the hole as you force it in place.

nico boom · Post by **nico boom** » Sun Jan 24, 2010 11:07 am

The awl [or pointed screwdriver] is clearly shown in the pics.

Question; how do you want to prevent the flat leads of the snap-in caps of touching the wick when folded like you suggest? Seems to me the leads will touch the wick in the hole, wether done it your way or mine, since the folded wick will cover about half of the hole. So I'm curious why you think folding the wick is better. [because it still does not prevent the solder from getting sucked into the hole by the wick when heated just a tiny bit too long or too hot].
Always wanting to learn.....

Post by **Eric D** » Sun Jan 24, 2010 11:56 am

This is really hard to explain without a photo or drawing. I will do the best I can.

The hole is about 1/16" diameter. The flat pin on the cap is about 1/16" wide, and maybe 1/32" thick. When you put the pin in the hole, it will touch the sides of the hole, but you end up with two half moon shaped voids which you want to put the wick into. If you have any of the wick in the wrong spot prior to putting the cap with its flat pins in, you end up wedging the wick in between the hole and the pin. This will further damage the fiberglass and the surrounding copper trace as the fiberglass compresses.

Folding the wick is not the big advantage to my method. I just don't know how else to get 1/8" wide wick into a hole which is slightly smaller than 1/8".

There is really no difference between what you posted before and what I posted now, other than I am using some text to explain what I am doing. I think your photos are kind of hard to follow without any explaniation. After going through your photos again I was very confused. In one photo you have a snap in cap, and in others you have a lead type cap. As for the awl, I had no idea that was what that is. It looks like a black oxide drill bit upside down more than a screwdriver to me (I use drill bits to clean out damaged vias sometimes, so I would assume that is what that is).

When people fix the vias they need to be aware of where the wick is going to end up, and I also think they need so make sure to tin the top side of the board, something you did not mention or show. Soldering the wick to the board without tinning the board is much harder.

I am not trying to steal your credit or anything, I am just sick of fixing these on people's amps, so I thought I would post something showing what to do. If that bothers you I apologize. I know I made a cap replacement tutorial way back when, but Jim Truett posted a far better way to do it which made my method obsolete. I really should just take mine down now as it is useless.

There is nothing wrong with progress to improve something.

nico boom · Post by **nico boom** » Mon Jan 25, 2010 11:11 am

I agree that conversations like this are a benefit for all who want to change caps; let's keep up the good work.

Post by **smgreen20** » Mon Jan 25, 2010 3:04 pm

How about a video??? The pics are very good and I liked how it was laid out, the only way to make it easier is to physically show via a video.
Other then that, I see no real issues with how it was done.

Post by **Eric D** » Mon Jan 25, 2010 9:10 pm

smgreen20 wrote:How about a video??? The pics are very good and I liked how it was laid out, the only way to make it easier is to physically show via a video.
Other then that, I see no real issues with how it was done.

I would be willing to give that a try. My only problem is my camera only shoots HD video as far as I know. The download would be massive.

Post by **fuzzysnuggleduck** » Mon Jan 25, 2010 10:10 pm

Youtube can convert the HD video into something easily watched. Or you could convert/transcode it and intentionally lower the quality to lower the file size and just host the video file somewhere.

nico boom · Post by **nico boom** » Tue Jan 26, 2010 11:48 am

My 2 cents about making a video; if someone still needs a video after reading everything that is written about this subject, and after looking closely at the pics.....maybe it's better to have it done.

There is not much left to tell/ show IMO ; carefully doing it, and getting experienced with a good soldering-iron plus these kinds of jobs is what really counts.
Start with a broken tv-set or something that has no value, and desolder all parts from the board; that's how I started more than 30 years ago.
[and I'm still learning

]