Soldering review

[vickyg2003]

I'm going to break out my soldering supplies and put some 6 pin head on.

I am trying to recall everything I was told.

1) Make sure both parts are clean, remove visible oxidation with pencil eraser.

2) Use plenty of flux

3) tin the iron, by applying a small amount of solder to the tip and let it flow around.

4) Position the pin firmly to the board, so that it won't move.

5) Apply heat to both parts at the same time. Am I supposed to only apply it to one side? Or do I walk the Iron all the way around the joint? Can't remember?

6) Apply solder to the parts NOT the iron. The solder is drawn to the heat. Touch the solder to the opposite from the iron and solder will flow towards the heat source. Is that at the joint? Did it walk up the pin to form that point?

7) Don't allow parts to move while cooling.

Keep tip of iron clean with wet sponge.

Use a lighter touch when doing wire soldering our you'll burn through the wire.

Good joints will be tiny and shiny and confined to the pad.


Am I missing something? Can you refresh my memory on this? Its been a long time since I used this equipment.

[The Robman]

Which remotes are you modifying as the process sometimes differs.

1) When I do it, I don't bother cleaning anything and haven't had any trouble yet.

2) I do use flux everytime, but I don't use a lot. The flux should help the solder form a perfect "Hershey's Kisses" shape rather than a ball shape.

3) tinning is good, but I rarely remember to do so, so it's not essential.

4) If you're adding the 6-pin to a remote that has holes in the PCB, like the URC-6131, URC-7800, etc you should first apply the flux to the PCB pads, then put the pins in place, then turn the PCB over, placing it on a heat resistant surface. I use a board place mat, which is also thick enough so that it holds the pins in place while I solder, so I have one hand holding the solder and the other holding the iron.

5) See what works. Basically, you apply the iron to the pin and pad together, then you bring in the solder. Hopefully it will flow all around the pin by itelf, but if it doesn't you can use the iron to help it on it's way. When you're done, you can always re-heat the solder to help it re-seat itself.

6) It's also drawn to the flux, so if the pin isn't hot enough to melt the solder by itself, you can touch the solder onto the end of the iron. If you heat the pin too much, the black plastic will melt (I've had it happen), plus if you heat the pads too much, they will come away from the PCB and be useless. I haven't had that happen to me, but I've seen lots of other people's remotes where it has happened.

7a) Yes indeed
7b) Sure, you can also get a small tin of cleaner that you can dip the iron into.



7c) If it's isulated wire, your main concern will be to not cause the insulation to melt

7d) yup, and more importantly, you shouldn't have any shorts between the pins, so watch for the solder going where it shouldn't. If you do get a short between the pins, try "swishing" the iron between the two pins as sometimes this can cause the solder to seperate, then if successfull, re-seat the solder on each of the affected pins

[jherrick]

Yes, everything that Rob said.

Only one thing that I should add, and that concerns #5. Reflowing (touching the iron to the solder after the first attempt) should only be tried once or twice. After that, the solder becomes comprimised and you can quite easily find yourself with a cold solder joint (bad connection).

I wish to emphasize #6. Depending on the size and wattage of your iron, you can quite easily melt the plastic that holds the pin, and the pin can go sliding on you. You want to be quick, but not so quick that the solder can't flow properly.

Jim

[vickyg2003]

Thanks Jim and Rob.

Rob I don't think tip cleaner would be overkill for someone who does 4 remotes every three years?

Jim, I don't know what the wattage of my iron is, but I do know that I don't have the patience to hold it on long enough to melt the plastic.

I hope I don't goof, because even though I've got a desoldering bulb and desoldering braid, I haven't got a clue how to use those tools.

[The Robman]

To add even more to #6, you should probably be using a low wattage iron. I use a Radio Shack 15w iron with a "pencil" style tip for remote work. I use a 30w iron for regular PCBs.

[vickyg2003]

1 down, 4 to go! This was really helpful to me. I've got 3 more 7800's that need the pins, and then the 6011 with the eprom and wire. I forgot just how tiny this stuff is. If I was going to do more of this stuff I'd definately need some type of magnifier.


If you were buying a helping hand magnifier would you get one of these
http://www.ehobbytools.com/en-us/dept_70.html
or is there one that's particularly good? I have lots of projects where I'm trying to hold everything at once. If I had helping hands, I probably wouldn't have burned my finger.

[The Robman]

I have one of the helping hands with the clips and magnifier (see below) which has come in useful on several occassions (but I don't think I've used the magnifier that much, I used it mainly to hold things while I soldered them). You could also consider one of those magnifiers that's on a headband.

[vickyg2003]

Okay, I did my upgrades, but now one of the units won't work. I can read and write to the eprom, but no LED and no signal.

What did I do wrong?

Can I fix it?

[The Robman]

Okay, I did my upgrades, but now one of the units won't work. I can read and write to the eprom, but no LED and no signal.

What did I do wrong?

Can I fix it?

You probably got one of the battery terminals trapped behind the plastic wall rather than in front of it.

[jherrick]

Which one won't work? One of the 7800s, or the 6011? If the 6011, make sure that your EEPROM is facing the right way. Sometimes pin 1 can be hard to identify.
Jim

[vickyg2003]

Its a 7800. and I don't have the battery terminal trapped. Its just not working, no signal, no LED.

[The Robman]

Do you have any of the buttons trapped into the ON position? Did you check for any shorts between the EEPROM pins and the 6-pin pins?

[vickyg2003]

Thanks for the idea. I thought since it could read and write, that there wouldn't be a short. I got out the magnifying glass and could see a big brown build up of flux between the two pads. So I scraped it clean with a toothbrush and scraped it with my fingernail. Put it together and now it works.

4 down, 1 to go!

[vickyg2003]

Another question. One of the remotes has a few buttons that won't work.

I had bought this item as an "open box" remote, but when I opened the packaging, it looked more like a well used remote that had been drenched in liquid.

I've tested the buttons and it is the board, not the button skin, that's the problem.

So is there anything that can be done to revitalize those black F looking contacts?

I remember years back when the kids nintendo got a social disease there was a plastic safe electrical contact cleaner that helped with this kind of stuff, but again that wasn't those soft buttons.

Any ideas?

[jherrick]

The way the buttons work is that when the button is depressed, the black conductive pad on the button contacts the two intertwined traces on the pcb, and completes a circuit. If your button pad is fine, and you say this board looks like it was in liquid, then the pcb traces may have a coating on them that is not allowing completion of the circuit.
You can take alcohol and a Q-Tip to remove most things. Try that first, and if that doesn't work then you may have to get more aggressive.