Safest desoldering strategy.

[project23]

Originally Posted by nolunchman

brownie points for creativity :^)

the major advantage of chip quick is that you dont need much heat at all. only takes a few seconds of hot air (i set mine at 300C) before it is molten, and it stays molten much longer than plain solder. for $15 you get maybe a foot of the stuff, but i think it's worth it.

Fantastic - going on on my list of things to get next.

[ElectroBlaster]

I keep reading and hearing really good things about Chipquick!

I am going to get some, any recommendations where to get it?

Also I need to rework an A2000 board, the joystick port needs restoring with a proper one (currently has a rather good hacked up one). Also a fuse of somekind has blown near that area so need to get that out and replaced.

I gather chipquick coupled with my solder vacuum station and maybe an smd heatstation, would really get this sorted out.

[plasmab]

I cut the soldered in chip out with lindstrom cutters. I keep the cutters well away from the board. I then flux up the remaining pins and remove them with the iron and tweesers one at at time.. then finally use desolder wick to remove the remaining solder.

[desiv]

Aaarrgghh!! :-(
Trying to solder in some new RCA jacks into my A1000.
Figure it can't be too difficult because they are large pieces.

Got the old ones out fine.
My replacements are exactly the same kind! Yay.

But... Those HUGE holes for the flat side connections....
How do I get the solder to stay IN the hole and not travel up the metal!!!!!
Grrrrr... ;-(
The more solder I add, the more solder flows up the metal toward the plastic on the jack. Why won't it stay in that HUGE hole!!! ;-(

[supaduper]

The large holes being ground planes have a bigger mass to heat up to soldering temp whereas the pins on the jack are a smaller ground plane mass so heat up quicker than the holes,so the solder is sucked up by the smaller hotter ground plane first.

So either you are using an insufficient soldering iron temp or tip I.E better to use a higher soldering temp with a bigger iron tip like a broad chisel tip a normal point fine tip will never work

[desiv]

Originally Posted by supaduper

So either you are using an insufficient soldering iron temp or tip I.E better to use a higher soldering temp with a bigger iron tip like a broad chisel tip a normal point fine tip will never work

I figure it is something like that, but I'll have to figure out the right combination.
I can heat up the solder fine, it's just that it tends to travel up/down (depending on the facing of the board) the metal from the jack rather than staying in the hole.
I'll see if I can find some similar hole I can practice with on some other board...

--

Unfortunately for me, this might be more complicated.
I was hoping to replace just the jacks and CAPs right around the audio area, which I did, but no change in my sound problem.
I'll move on to a full re-cap next (probably should have done that initially, but..).
If that doesn't do it, I'll probably be looking for someone who can troubleshoot/repair an A1000 board in the US.
--

[supaduper]

Also use a thicker gauge of solder like 1.5mm.
Fine solder will be a waste of time on holes that large as you need to get the solder to pool quickly, so thicker the solder the better

[dalek]

if you are still struggling, a quick hack might be to fit the jack, then on the solder side, wrap some short lengths of solid copper wire around each flat leg flush against the pcb to bridge the gaps.

[ajk]

Solder will not stick to cold parts; you need to get both the board and the jack hot enough so that solder will melt on contact with them. Generally speaking you never apply solder wire directly to the soldering iron itself (except to have a thin coating on the tip to facilitate heat transfer).

With large copper planes on the motherboard getting everything up to temperature can require considerable power from the soldering iron. A larger tip may also help. If there is a big mismatch in the size of the parts being soldered, you probably need to first heat up the larger part in order to not overheat the smaller.

[plasmab]

Originally Posted by ajk

Generally speaking you never apply solder wire directly to the soldering iron itself (except to have a thin coating on the tip to facilitate heat transfer).

And except when drag soldering smd parts.

I always apply solder to the tip. All the time. But I drown everything in flux.

TBH there are no hard and fast rules in soldering. It’s a bit like using a paintbrush. It’s art. Whatever gets the job done.

[ajk]

@plasmab

Absolutely, once you are comfortable with the process, there are many ways to skin a cat. But what desiv described is a common issue or misconception beginners face; you in fact can't just spread solder on cold surfaces like paint with a paintbrush

More heat, more flux and it should work out.

[desiv]

Originally Posted by ajk

Solder will not stick to cold parts; you need to get both the board and the jack hot enough so that solder will melt on contact with them. .

Thanx!
I think part of my problem was that I was trying to do that, but the little jack is going to get hotter much quicker than the board.
So the solder was climbing down the hot metal on the jack and the board was probably just barely getting warm.
I am a bit nervous about getting the board itself warm, but I supposed that spot is designed for it..


What temp would you guys recommend?

[obitus1990]

350C on a good iron (like my Hakko FX-951) and a large hoof shaped tip has worked fine for me for this kind of application. Maybe a little hotter (10C at most), but, the large size of the tip is what keeps the heat from being sucked away by the ground planes as much as it would if you use a tiny tip.

[ajk]

@desiv

Parts with significant difference in heat dissipation capacity can indeed be tricky; I suggest you keep the iron on the through-hole for as long as it takes for solder to flow onto it, and only then make contact with the leg of the jack. If you can find a roughly similar scrap PCB to practice with, it would be a good idea to do so.

If the solder doesn't flow in any reasonable time, the soldering iron probably just isn't powerful enough or the tip is too small to effectively transfer the heat as kirk_m also suggests. Do you know what wattage your iron is?

[desiv]

Originally Posted by ajk

I suggest you keep the iron on the through-hole for as long as it takes for solder to flow onto it, and only then make contact with the leg of the jack. If you can find a roughly similar scrap PCB to practice with, it would be a good idea to do so.

I'll try that. I've been looking for a scrap PCB to practice with. Think I'll have to take apart some more junk.. ;-)

Originally Posted by ajk

If the solder doesn't flow in any reasonable time, the soldering iron probably just isn't powerful enough or the tip is too small to effectively transfer the heat as kirk_m also suggests. Do you know what wattage your iron is?

It's a 60 watt Hot Air / Iron Solder rework station so I think the equipment can do it... Just not yet sure about the operator. ;-)


Thanx!