Soldering/Repair Tutoring..

C-pher

C-pher

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I've love to up my skillz on working on my radios. I just have the balls to jump right in where I haven't really done any soldering.

I have two SWR Meters that need to be fixed and a radio that I need to changes out the lights.

I would like to have someone watch over me...or direct me on how to repair them.

I'm a'scared!
 
I had picked up a wheeler soldering station years ago that served me well. Don't expect that one to do everything. You will need a higher power one for soldering coax and stuff requiring more heat. Radio shack used to sell what looked like a fine brade made out of copper and you would put that over what you were trying to unsolder and it would wick up the solder. Just place over the solder then heat the brade and it would wick it up into it then throw that piece away. They also make a squeeze bulb that you heat the solder then suck it up into it. The good news is its not hard to find old junk to practice on till you get your confidence up.
I had made lots of old Heath kit stuff like clocks and swr meters etc and it was lots of fun. I found it useful to have one of the flex lights with the magnifiers on it. Pick up some decent quality small screwdrivers, needle nose pliers. wire strippers etc.
Jump in and practice on the junk FIRST or you may make more of it :)
 
They also make a squeeze bulb that you heat the solder then suck it up into it.
Click to expand...

The squeeze bulb works, but I prefer the spring loaded doohickie - you cock it, stick the top on the blob of solder you want to suck up, and push the button and "foompf".

The most important things to understand are how to solder without putting excessive heat on other components, and how to recognize and avoid cold solder joints.

Now, if you're talking about working on SMT devices, you're entering another realm and will want specialized tools, magnifiers, etc.
 
I prefer solder wick myself. Every time I tried using the spring loaded doohickie it always looked crappy. It might be good for getting the heavy out of the way, but i always go over it with the solder wick to pick up the lighter stuff. If you buy solder wick, make sure you buy the stuff that already has flux on it. I didn't know you could buy unfluxed solder wick, and bought three spools of it for out lab. Not a huge deal, but it's a small hassle to have to flux up the wick before you use it.

The hardest part IMO is applying enough heat to make the solder flow without baking the pads/via holes off the board. Here's a decent guide on soldering i found online.
http://www.ece.ualberta.ca/~ee401/resource/manuals/Solder01.pdf
 
I start with the springloaded sucker and often clean-up with the wick. What really helps the wick and some other tasks is to add a little flux. I like my flux pen (like a felt tipped marker loaded with flux). I draw on the wick with the pen and the wick wicks much better.
 
cockpitbob said:
I start with the springloaded sucker and often clean-up with the wick. What really helps the wick and some other tasks is to add a little flux. I like my flux pen (like a felt tipped marker loaded with flux). I draw on the wick with the pen and the wick wicks much better.
Click to expand...

yeah, that's what we have at work(flux pen). They work great!
 
If you need to work with SMT devices, I used to (back in my motherboard repair days) cut the pins off the side of the package (with an Xacto) and then use a braid to clean up the pads. I used to hand solder them back on, one leg at a time. Just use an iron with a very fine pencil tip and .25mm solder.


When repairing any device, check the power supply. Look for any bulging or misshapen capacitors replace them if you see anything unusual.
They tend to dry out and will cause problems.
 
They sell kits that will help you build your skills. Some of them can be fun and they start at around $5 or $10.
Or you can build a dummy load like I did. It had dozens of resistors and by the time "I" was done my son was pretty good with the soldering iron.
 
For practice, pull apart a piece of electronics junk you haven't gotten around to throwing away. See if you can take a few parts off then put them back on again.
 
Weller makes a number of good soldering irons....and you can buy them at local stores including You-Do-It (http://www.youdoitelectronics.com/id100.htm).
I have a variety of irons for different jobs, remember you can also buy different sized tips. There are also various types of solder wicks (http://en.wikipedia.org/wiki/Solder_wick) depending on the size of the job. Practice makes perfect...try soldering together some wires or removing components from an old circuit board. Don't use the soldering iron as a repository of molten solder...only to heat the wire enough to get the metal to flow. Too much heat will damage the board and/or components, it's important to match the iron with the job. Happy to help if needed.
 
The basics:

Here's everything I can remember from a former life where I did this daily:

- Make sure all of the areas to be soldered are clean and shiny. Scotch brite or #400 sandpaper are not out of the question if you're working on older equipment, and are great to clean up the tip of the iron when cold.

- "Tin" the tip of the iron with a little bit of solder before you start.

- Be sure to use enough heat so that the solder flows when touched to the joint at the opposite end from the iron. Don't try to use the iron to melt solder into your joint.

- For heat sensitive parts, get in and out quickly. Your goal is to get the joint hot but don't spend so much time that you heat up the whole part. If your part is getting too hot before the solder flows you may need a hotter iron, which sounds counter-intuitive. You can also use clip-on or paste heat sinks to keep the heat away from the component.

- Use a damp sponge to wipe off the tip of the iron to keep it clean while you work.

- Don't try to use solder to substitute for a poor mechanical connection.

- Different solders melt at different temperatures. If you're trying to de-solder an SMD (like free-banding your Yaesu) good luck....

- Get both the solder wick (copper braid) and a sucker device. You'll use them both.

Geoff
 
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Have a wet rag (or sponge) on the station, when the iron is hot, rub it down well, and apply a good tinning of solder. Then remove any excess.

Also, try to make all of your joints mechanically sound before soldering. Think of solder as a final paint on the joint to ensure good electrical contact, but it will not hold up mechanically.

Make sure to heat the parts of the joint, and not the solder, then as with plumbing, add just a paint of solder directly to the components, not the tip of the iron. Solder will always be drawn toward the heat, so if you touch the iron, the solder will go nowhere.

Use a thinner solder (rosin core) of 63/37 blend. You will have more control (and a lower melt point) than with thick stuff. (If you can only get 60/40, that will work okay too) just don't overheat the joint.

Too funny, I guess I had the same memories as Geoff.
 
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Hello C-Pher,

I live in Mansfield, and am the Chief Engineer of an Electronics Research and Develpement company here.

I have over 40 years experience designing PC boards, circuit design, and soldering anything from the smallest Surface Mount devices all the way up to 1/0 Litz Wire for High Voltage power supplies.

If you buy the beer, I will gladly invite you to my shop on Saturday and teach you anything you need to know. From assemble to rework!

I also have a shit pot of test equipment and anything you would ever need to borrow anytime.

Just send me a PM and I will give you my phone number. I would be honored to help you.

(And those guy's that recommended a spring loaded solder sucker are giving you bad advice, those things do nothing but lift pads and damage boards. Only use Solder wick!)

EDITED TO ADD: All the rest of the advice here was excellent!
 
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Skysoldier said:
Hello C-Pher,

I live in Mansfield, and am the Chief Engineer of an Electronics Research and Develpement company here.

I have over 40 years experience designing PC boards, circuit design, and soldering anything from the smallest Surface Mount devices all the way up to 1/0 Litz Wire for High Voltage power supplies.

If you buy the beer, I will gladly invite you to my shop on Saturday and teach you anything you need to know. From assemble to rework!

I also have a shit pot of test equipment and anything you would ever need to borrow anytime.

Just send me a PM and I will give you my phone number. I would be honored to help you.

(And those guy's that recommended a spring loaded solder sucker are giving you bad advice, those things do nothing but lift pads and damage boards. Only use Solder wick!)

EDITED TO ADD: All the rest of the advice here was excellent!
Click to expand...

That's very cool of you. I am SO up for that. Thank you! I'll be more than happy to bring some beer!
 
My Dad was an engineer on the Minuteman missile systems. He taught me to solder at a young age. We built lots of stuff together, including a shortwave radio and other communications equipment.

The mention of solder has brought back some good memories...
 
Skysoldier said:
And you guy's also forgot the first rule of soldering......

Never try and catch a falling soldering Iron![rofl][rofl][rofl]
Click to expand...

I remember when I was a teenager. I was installing a new stereo system in my car and decided that I wanted all the connections to be soldered. Wire nuts weren't good enough:) I was on my back under the dash, feet up on the driver's seat with my arms weaved up into the area behind the radio. I dropped the soldering iron and it landed on the inside of my bicep. Ouch! Of course it took me a few seconds to get my hands down and out. That was over 30 years ago. The scar is almost gone.
 
I also wanted to add that I have a shit load of obsolete SMT parts and circuit boards you can take home to practice with.
 

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