I and my mother soldered the stupid 12 voltage regulator several times. It worked for a while and the intellivoice wouldn't work. The ribbon cable got stuck under the brown part for the controller and it is ripped now. For some reason the solder on the 12 volt voltage regulator would not stick it kept coming lose. Why can't this stuff just work. I am sick of replacing , soldering ,and opening because of things that crap out for no reason. I just want a reliable working intellivision. I was sweeting like crazy soldering this thing.
You should be using 60/40 tin-lead solder (it's easiest to work with), and a soldering iron suitable for electronics work. Ideally a temperature controlled one, so you can boost the heat when needed.
If you have a temp controlled station, I find around 300-310 degrees C works for most general work, boosting the temp up a bit for ground planes.
1. Tin the tip of your iron (melt some solder on it and wipe on the wet sponge pad or use a wire wool cleaner), the tip should be bright silver
2. Optionally add flux to the joint (you can buy flux pens cheaply at the electronics store, it will last you ages)
3. Heat the joint with your iron and add new solder to the joint to help the old solder melt and flow
4. Use a desoldering pump or braid to wick away the old solder
5. Clean the pad using isopropyl alcohol and cotton tip
For a good solder joint...
1. Optionally apply some liquid flux to the pad being soldered
2. Heat the joint with the tinned soldering iron for a few seconds FIRST, then apply solder to the joint (NOT the iron!). The solder may not form a nice cone initially, keep the heat on it and it should flow into the correct shape and stick when it reaches the right temperature. The solder should flow easily into the joint when it's hot enough, almost instantly in most cases. If the solder doesn't appear to stick after several seconds of direct heat, either your iron isn't hot enough (check if you are soldering a ground plane connection), or the surface being soldered is not clean enough.
3. Clean away any leftover flux with isopropyl alcohol
The pads on the regulators are not very large, so be careful not to feed too much solder in. If you do, you can always wick or suck some solder away and retry. Be careful not to lift the pads. If the pads lift it's not the end of the world, you can work around it.
Note pads that are connected to large trace areas eg ground planes can require more heat.
If the solder is not sticking, then either the pads are dirty, or you didn't use enough flux, or you used not enough heat.
Ripping the ribbon cable - Ugh, not ideal, these are so fragile and fall apart so easily. Try taping it to keep it together but check continuity is good. Someone on here did have some new old stock ribbon cables, but you can replace the 5 pin connectors with 2.54mm 5 pin connectors and some ribbon wire. Eg: