Soldering?

[avg1joe]

I have a handful of computers with some bulging capacitors on them. I would like to learn to replace these. Anyone know of a dvd, vhs tape, good book, website etc. that would help me teach myself to solder in general or solder capacitors on motherboards specifically?

"Just replace the motherboard" "Its not worth the time"...

I have time on my hands and would like to learn how to do this just for the sake of learning. If I screw up these boards any worse it won't matter.

 

[mike123abc]

Last time I soldered something difficult (a combination of metals that rejected normal solder) I went to youtube for tips. There were quite a few good tutorials.

 

[tracker1998]

Use as little heat as possible. You may not have success as some boards are "multi" layered.
Be careful when working caps. They hold a big charge for a long time!! I have a freind that accidentally discharged one, (not a small one) but none the less, a big ball of blue flame knock him across the room.

 

[avg1joe]

a big ball of blue flame knock him across the room.

Cool!

I mean, is he alright?

 

[tracker1998]

LOL little burnt hair, but I remember him telling me that it really rattled his brain!!! LOL.

 

[tuberadio]

As I work in the computer field... Just replace the boards... but the Ham Radio Operator in me says, fix it...

I suggest a good soldering iron... Personally I use a Weller soldering station, temperature is variable, many different tips... Even a cheap 25W (dont get thoes junk dollar store units!) iron should be more than acceptable for the task. Stay far away form the dreaded solder gun... they are too big and too hot for what you need to do.

Get a solder sucker or even better some soldering braid.

Make sure to replace the caps with the same voltage rating and same value... the voltage rating could be higher with out problems, but dont change the actual value of the cap... if it is a 100uF cap, dont put a 110uf or a 90uf cap in there.. replace it with the same.

The voltages across the caps shouldn't be too bad... 5 to 12 Volts.. but I would still suggest discharging them through a 100 ohm 1W resistor, just for safety sakes.

Find out if the board is RHOS... because you may need to get lead free solder... but personally, I would use good old 60/40 or 63/37 Lead / Tin solder....

Use Google, and you will discover many soldering tutorials... check out some desoldering tutorials as well... you are going to need to remove the old caps.

Go take a visit to your local electronics shop... they may be able to help you get some of the tools you may need to start your project....

I hope this gets you off to a good start.

Let us know how this turns out!

 

[avg1joe]

All good information. Thank you.

 

[avg1joe]

I'm trying to put a shopping list together.

Would a weller 40w iron from home depot be a decent place to start?

I have seen stick type suckers and bulb type suckers. Any preference? Do you need a sucker and braid or one or the other?

Where would you recommend getting capacitors? Can they be found in chain stores or just the net?

How do I pick out the right solder to solder on the new one. What size, etc?

 

[SparksPA]

Here is a good deal on a very good soldering iron: FRYS.com | Hakko

If you are in the Phoenix area I understand that they may have an in store special right now that may make them even less expensive. I have had one of these for several years and it serves me very well. It is much better than the cheak knock-offs that look similar but are unreliable and difficult to use. I am not familiar with the Weller unit mentioned earlier but I suspect that it would be similar to the Hakko unit in the link above. Hakko makes commercial soldering stations as well. I would consider this one to be an excellent unit for an avid hobbyist but not quite up to commercial production use standards. The price is not in that range either.

 

[tuberadio]

Would a weller 40w iron from home depot be a decent place to start?

Yeah, thats a good place to start... check the link SparksPA send.

I have seen stick type suckers and bulb type suckers. Any preference? Do you need a sucker and braid or one or the other?

I like solder suckers for lots of solder.... then use the braid to clean up. I have used both bulb and the spring loaded type. Its all preference.... personally I only use braid... I have 4 or 5 different widths for to suit different tasks.

Where would you recommend getting capacitors? Can they be found in chain stores or just the net?

Around where I live, there are 2 places to get them.. locally run etc... but the prices are ridiculous... Try Digi-Key or Mouser... Google will return their website for you. Sometimes, eBay will have some OK prices on a whole pile of one item... Occasionally I order stuff from eBay to 'Stock Up' on things like resistors...

How do I pick out the right solder to solder on the new one. What size, etc?

There are many sizes of solder... but for most applications 0.80 mm dia. 63% Tin / 37% Lead works quite well... You could even go a size thinner.... Too much solder on a solder joint is a bad thing.

 

[tracker1998]

It's sad that Radio Shack, well here in Canada (don't know about the U.S. as they still exsits on the web), turned into The Source. There, one could walk in there in the morning and have a power supply or whatever the day's project was, built by early afternoon with your own etched circiut boards, case and all other parts needed for a project.
Spent wise money there and still have many projects I have made still in use today including my favorite little amp driving my surround sound sub-woofer.
In the old days, one could approach a local repair shop and order hard to find parts. Maybe more expensive but you could get them.
I have a scope and frequency counter, tube testers and all kinds of other things that one can't even give away today!!! LOL.
Today is a "throw away and replace" the board or whole thing society.
I hope you have success avg1joe and let us know how things turn out.
tracker.

 

[avg1joe]

Today is a "throw away and replace" the board or whole thing society.

Sadly true but I think some people are coming to their senses and becoming more frugal. I supplement my finances by watching freecycle, craigslist, and the other local classifieds.

Recently I pieced together a couple free desktops to make a better one. I ran it for a few months and traded it for a laptop that needed repair. Fixed that up and sold it. The woman who bought it gave me cash plus a desktop for free that is better than the one I traded for the laptop in the first place.

Replacing capacitors will open up all sorts of new possibilities like this.

 

[Dhave_Malloc]

I just ran across this site last week.

badcaps.net

It might, might not help you out!

 

[harshness]

I think we can agree that the basic tool we're looking for here is a soldering PENCIL, not an iron.

A desoldering setup of some sort is often useful where multiple pads are involved and the components are down so tight that they won't rock. Wick type is often the easiest to use but it can be slow. The big boys use vacuum bulbs for speed and complete cleanout.

The key to a successful component replacement lies in not cooking anything and making a good connection when you put it back together. You could spend a day just learning how to identify bad soldering (icicles, cold joints).

Choosing a proper solder and solder diameter is also helpful. I have a big roll of small diameter quad-core 60/40 solder that has served me well over the years. I'm still not sold on lead-free solder.

 

[tracker1998]

harshness makes a good point about a good solder joints.
Sometimes, things seems like they are soldered properly but are not. This is a common problem area that simple quick research can avoid big future frustrations.
He mentioned as I did as well, keep it as cool as you can.
When you see the process of soldering a board, it floats quiclky across solder with all the components in place in one shot.
The traces are narrow and the film coating the board is also thin due to this process.
Plug away at it! Steady hand! And if your like me ,, were your glasses!! LOL
Idea, I used to use "helping hands" which are alligator clips attached flexible wire of some type to help hold parts in place. These can be found in dollar stores and are a must in your tech tool box.
Have Fun!!

 

[avg1joe]

I finally got a chance to try this out. I tackled a Dell gx270 with 5 bulging caps. The process was nerve racking and would be easier with more expensive gear but the computer is running flawlessly now. I'm ready to attack the small stack of computers in my basement.

Thank you all for your invaluable advice.