Don't know if I would qualify as an authority on this. I have a lot of soldering experience, but only surface mount stuff have done is to replace a bad part.
I just recently removed/replaced a bad surface mount on a 6 channel master hub and technique worked.
- I wouldn't paint flux on the board, but most of your solder you get on a spool is called rosin core solder. It has flux in it to help the solder flow better. Here is an example:
Rosin Core Solder. That is what I would use.
- The solder pads on the circuit board probably have a thin layer of solder on them. Not sure how much though since I am usually in the capacity of replacing a part that has already been installed. When I replace a surface mount I clip the legs of the chip on on it. Then use solder wick, called solder braid here:
Solder Braid to suck up the excess solder from the pad or to expose the hole. If it is a diode or something I use the solder wick to help remove the part.
Put a tiny bit of solder on each pad or at least one. Then position the part on the pads. Hold it down with a pointy thing to keep it in place. Then quickly touch the pad/pin junction with the soldering iron to melt the solder and make the part stick. Then move on to the other legs and touch the soldering iron to the pad/leg junction to secure the other legs of the part. Then come back to the first leg and secure it.
Some people put too much solder or hold the iron on too long. You don't need a lot of solder, just enough to make the junction. If I get too much I will remove it with solder wick and reapply the proper amount of solder. Don't hold the soldering iron on the pad or part for long at all or you will risk lifting the pad or ruining the part. Basically have everything ready, quickly put iron to junction, then quickly touch solder to junction. Then remove both. Don't move part for few seconds or risk bad solder joint. If didn't get enough solder,... I blow on the part and wait a bit for it to cool before attempting to fix my error.
Am I confused about the pre-flowed solder? Should I have used solder for all contact points?
I think the pre-flowed they are refering to is the solder already on the board when you get it. But unless you have the same kind of equipment you are going to have to solder the parts on. Use a small tip iron. There might be enough on the board to make the part stay, but I would apply a tiny amount to each leg/pad anyway. Here is how they make surface mount boards:
Wiki Surface Mount
I just checked continuity on some of the parts and there doesn't appear to be any continuity through the regulator.
Depends on how you are checking. Some meters have a diode check setting. You might get low value when forward biasing and high or open when reverse biasing the part. But if you measured your regulator and got the same reading forward and reversed biased you probably have a bad part (but that is for diodes/transistors, regulator might not read the same). If you are using the resistance setting on the meter like you would check for a short/open or resistor measurement and got continuity (assuming you mean no or very low value), then you would have a short in the regulator, which isn't good. Here is how to check components:
Test Components
Also note that lot of times you might get a different reading if the part is in circuit (attached to board with other components). Then you have to look at the schematic and might even have to lift another component to test a part.
Hope this helps. If you don't have much experience soldering. I would go to radio shack or somewhere and get some of those perfboards with holes and solder pads and practice maybe putting a few old resistors, caps,... in. You will get the hang of how much and how long to hold the iron.
Here are a few sites I just found on how to solder:
How to Solder 1
How to Solder 2
Just type 'how to solder' in google and you will find a lot.
I read one posting about a bad regulator. Where would I probe it to test it?
Well, look at the schematic and trace it down on the board where the OUT pin is and measure from ground to the OUT pin. Or looking at the schematic I can see if you measure from ground to JP2 jumper you will read the OUT from the regulator and if measure from JP1 to ground you will read the input voltage to the IN on the regulator. You should be able to find ground on the negative side of the filter capacitors C4 and C5 by the regulator. I am just looking the schematic and if it is accurate you should be able to find the points to measure from on the board.
I'm not sure which package the regulator on the board is using but you can find the pinout here:
LM78M05
The regulator appears to putting out .3 mV on the center pin and 5.12V on the third pin. I reversed the green LED and it works! I'm assuming I need to reverse the other LEDs as well.