Need serious help with soldering

This is in relation to my thread on the Sega -> Sega CD forum about fixing a SegaCD I found.

SegaCD No Worky

The following is a copy of my latest post in the thread which details my troubles with soldering. Any help you can give me will be greatly appreciated!

SegaCD Yes Worky!

But not without a long, tense, painstaking battle.

Most of the problems caused by my apparent inability to solder. Solder will simply *not* melt on either the tip of the iron or on the wire the iron is touching when the iron is touching the wire. (referred to as problem A).

When the iron is not touching anything, I can melt solder by touching it to the iron (30w). When the iron is touching metal wire or connection point, I can still melt solder farther up the shaft of the iron, but i can no longer melt solder within 1cm of the tip of the iron, and solder will not melt on the wire or connection itself. I bought the .032 60/40 Rosin core solder that was recommended I have 22gauge wire (it was the thinnest stuff they had at radio shack, would have preferred 24).

Since a proper solder joint requires the solder to melt on the wire/connectin itself (they have to be hot enough so the solder flows instead of balls), obviously I had serious troubles.

I also was tinning the iron before every attempt (thousands of attempts) by melting solder on the top and rubbing the sponge.

So basically, here's how my half a day went:

First, I opened up my old receiver (which my wife destroyed by plugging it directly into a wall outlet without a surge protector), and de-soldred the fuse-clips from it.

Then, i de-soldered the fuse itself on the segaCD. This wasn't an easy task since the solder wouldn't melt if I touched the iron to the fuse leads, I had to touch the solder itself. This leads to problem A.

Problem B: the solder remained inside the hole. The tip of the iron wasn't long and pointy enough to reach all the way inside the PCB wire hole, and the solder won't melt just by contacting the the iron with the connector, or a wire touching the solder. And the de-solder vacuum didn't such all the solder up when I was removing the fuse. So there was a thin by strong barrier of solder in the PCB hole, preventing me from sticking my wires in. After an hour of trying to get rid of the solder using the iron, wires, and de-solder vacuum, I eventually just pounded the sharp tip of a nail into the hole with a hammer. It worked, and I managed to not damage the rest of the board. I wore-off some of the sides of the hole connection, but enough was left for it to still work, and I could not fit a wire through the hole.

Next, I soldered wire to the two ends of the fuse-clips. The clips had a short stub that I could use to fold over the wire, and I also folded the wire itself, so as to create physical strength at the joint. Most of the hundreds of attempts at getting solder to melt at this joint were unsuccessful. Somehow I just think the wire and the fuse clip just sucked heat off the tip too fast. Most of the tip the solder would just bead into a ball, if I could actually get it to melt near the tip, and not stick at all. Eventually I got 2 good solder joints, and a couple of embarassingly ugly but sturdy-enough joints, such that the fuse clips are now rasonably firmly attached to the wire.

I believe at this point, I had burnt a 1/4in welt into the side of my left ring finger, and singed most of the hair from my right pinky. Holding the soldering iron "like a pencil" has the ill effect of me mindlessly grabbing too far up the shaft with my fingers, among other mindless acts.

The last part was the solder the wires into the holes on the PCB. I bent the wires at the bottom after inserting to add physical strength. Then tried soldering. I needed solder to melt down the wire to fill in the hole, to make sure the wire would connect to the leads in there (since I'd damanaged the contact points with the nail). Unfortunately, due to problem A, solder won't melt on contact with the wire. I even try getting the melt started by touching higher up the iron shaft, where it does melt, and then dragging the molten ball down the shaft towards the joint, and the ball actually freezes solid by the time it reaches the tip, since the tip isn't hot enough to melt the solder.

By sheer miracle, for one breif moment, solder magically started flowing down the wire, and formed a beatiful joint as it came out the bottom (actually the top of the PCB). I tried again and again to get more solder so I could also have a good connectio non the top as well as the bottom, but no luck.

I even tried my variable-watt iron, which can dial from 10 to 100w. Believe it or not, even at 60w, it seems to have a harder time melting solder on the tip than my 30w. And I couldn't get it melt anything at all when touching the wire. It just plain doesn't make sense. The god of solder must spite me. I didn't want to try higher than 60w while in contact with the PCB.

For the second wire connection on the PCB, I managed to get a "good-enough" but awful ugly solder connection.

I also managed to give myself a third degree burn on my right index finger. It turned that crusty yello look that hot-dogs get when you cook them over the first right before they get burnt. I also almost melted through the cord on the soldering iron. Man that cord just won't get in the way.

I decided not to solder the batter back on. I just stuck with my original trick. I put some styrofoam underneath to prop the bottom-contact up, and twisty-tied the batter so it presses down against the contact.

Using the fuse-clips is nice. Now i can just pop-in and out fuses without having to resolder anything. I popped in the 2.5A fuses I got at radio shack, and it blew out the moment I plugged it in... I was gonna scream. But there was no smoke or blue lightning, so I hoped the unit was still OK, and it was the power outlet or something.

Luckily I had some 8A fuses around from when I'd tried to repair my receiver. I plugged in an 8A fuse, and walla, it works! For the record, the 2.5A fuses where 250V fast-acting fuses from radio shack. Is there anything about that particular type that would cause it to not work? (they didn't have 120V, does that make a difference?).

So in the end, I'm rewarded with a working SegaCD Model 1. Whoever buys it from me may wish to re-solder where the wires connect to the PCB...

So, I'm left worried. My next endeavor was to finally put my multibios on my old segaCd model 1. Clearly, if I can't even melt solder on a joint, I'm screwed. I need any help you can give me!

When I was modding my genesii in the electronics lab at school, I never had this kind of trouble! They had a temperature controlled soldering station. I'd just crank up the temperature, and solder would melt easy and create perfect joints. I'm thinking I should pick up the 60$ digital temperature controlled soldering station I saw at radio shack. Of course that's a lot of money to spend just to play ranma 1/2 on the segaCd. I could just buy a darned japanese megaCD on e-bay for the money I've invested into my home electronics lab!

Obviously every other person in the known world had no troubles soldering electronics with their 30w (or even 15w) soldering irons. What in the world am I doing wrong?


I don't see any mention of cleaning the iron. Because of the heat the iron tip and anything clinging to it will oxidize at an accelerated rate, which usually leaves you with a sort of "crust" that doesn't transfer heat very well. It really ought to be cleaned every few joints but sometimes you can get away with more. Normally an iron is cleaned by alternately tinning the tip (coating it with solder) and wiping it on a wet sponge (note that it needs to be actual sponge; plastic tends to melt/burn, and those fumes generally aren't good for you). There are also "tip tinner/cleaner" compounds which are a kind of solder/flux paste that you dip the iron into. I've never found these to be necessary but some people swear by them.

As for getting solder out of tight spots, there's really no substitute for desoldering braid. The stuff is like magic when used properly - just get the braid between the target joint and the iron and if you have a good transfer the solder will flow right into it. Just don't forget that you need to remove the braid when you remove the iron. ;)
I was tinning the iron regularly, at least as best to my knowledge of how to tin it (I've never had hands-on instruction).

The 5th paragraph below "Sega Yes Worky" I wrote:


I also was tinning the iron before every attempt (thousands of attempts) by melting solder on the top and rubbing the sponge.


But there's so much rambling I did in my post it's easy you could have missed it.

Basically, I have a ball of solder laying on the wood block (that I'm using to solder on). It's a conglomeration of previous unsuccessful solder attempts. I touch the tip to it, and it melts into a ball, and then I rub the tip around the molten ball of solder, and then rub the tip on the wet sponge (it's a real sponge, it's attached to a soldering stand I got at radio shack). I was doing this inbetween every attempt (many hundreds of times probably).

The tip looks pretty clean. To contrast, the big tip of the stained glass soldering iron (the variable wattage one) looks pretty crusted up, but none of the discoleration comes off during tinning.

I have this container full of this green goo. It says tinning flux, but for lead-free solder only. I don't think the solder I'm using is lead free. Also, I'm not quite sure what to do with it. It just evaporates on contact with the soldering iron.


Just reusing a solder ball won't do quite as well as using fresh solder because you'll have already burned off the flux.

I have this container full of this green goo. It says tinning flux, but for lead-free solder only. I don't think the solder I'm using is lead free. Also, I'm not quite sure what to do with it. It just evaporates on contact with the soldering iron.

Flux is basically a cleaning agent, it boils/burns and the resulting reaction is supposed to break up any oxide layer on the iron/joint.

That being said, soldering is supposed to work like this:

- Set up the joint mechanically

- Clean the iron

- Tin the iron (with a thin layer, if a drop forms that's large enough to swing around there's too much solder)

- heat the joint

- add solder to the joint until it's fully wetted; usually it works best to add it from the direction opposite the iron

- remove the iron

If this doesn't work, something may be wrong, either with your joint (e.g. dirty or loo large i.e. sinking too much heat; this can happen with low-power irons and heatsinks) or your iron (e.g. dirty/damaged tip, tip not properly installed defective heating element). In my experience the two biggest problems are a dirty tip/joint and thinking you have more contact between the iron and joint than you actually do. Keep in mind that anything the tip touches will be sinking heat out of it, so you want to get as much contact with the tip as close to the joint as is feasible. Also, I'm not 100% sure about this since I haven't messed around with it in a while, but I think a typical cheap iron can only maintain peak heat for a few seconds after being applied to a joint, so you might want to try leaving more time between unsuccessful attempts.