Joint won't desolder!!!

ezietsman

Put solder on the iron. Use a big tip. Put liquid flux in the braid (if you have). It won't all go into the braid in one go.

AlanRatcliffe

Make sure your iron is big/hot enough, especially if it's a joint on a bigger piece of metal (like the back of a pot or an earth bus).

DDR4LYF

what wattage iron do you need for those temperatures?

aja

Sounds silly, but melt extra solder into the joint to make a big blob, then try desolder it.

Pump? Only good for large through hole components.

Small components need braid.

A small trick is to hold the PCB or whatever in your hand, heat the solder joint to melting point with the soldering iron, then immediately whack the PCB on its edge onto a hard table top. If you do it right, the molten solder flies off the board without damaging anything...

Psean

DDR4LYF wrote: The videos look so easy! How do you do it? I can't get the soldering vacuum or the desoldering braid to work!!! What am I missing?

What are you desoldering? My iron's 45W and I've only desoldered cables and that sort of thing so far but I've had plenty success with a pump . I just had to get a decent amount of heat into the joint and add a little bit more solder to get some flux running in.

AlanRatcliffe

DDR4LYF wrote: what wattage iron do you need for those temperatures?

30W-60W usually does the job. As others have said a bit of flux helps as does tinning your iron tip before desoldering. I find my pump very useful, but the solder has to be liquid.

DDR4LYF

aja wrote: Sounds silly, but melt extra solder into the joint to make a big blob, then try desolder it.

Tried that, no luck.

I'm trying to desolder blown transistors in a power amp.

My iron is a 30W, at the bottom of Alan's effective range.

aja wrote: A small trick is to hold the PCB or whatever in your hand, heat the solder joint to melting point with the soldering iron, then immediately whack the PCB on its edge onto a hard table top. If you do it right, the molten solder flies off the board without damaging anything...

I'll give this one a try!!!

I'm going to get a wide tip and try again. Thanks for the advice everyone! I'll let you know how it goes when I try again on Monday.

Wizard

DDR4LYF wrote: My iron is a 30W, at the bottom of Alan's effective range.

Probably your problem ...

A small trick is to hold the PCB or whatever in your hand, heat the solder joint to melting point with the soldering iron, then immediately whack the PCB on its edge onto a hard table top. If you do it right, the molten solder flies off the board without damaging anything...

Use a similar method.
Melt the solder, then flick the board towards a piece of newspaper.

Shibbibilybob

How are the transistors mounted?

Careful when flicking warm solder...it's very warm.

exsanguinator

30w is big enough to damage your pcb board if too much heat is used on the join...especially if you are battling to get the solder off..

DDR4LYF

Sorry that I could only get back now. The flicking knocking of the circuit board worked pretty well. I ended up just clipping the blown transistor off and pulling the little pins out one by one. The amp is back together and so we'll see if I damaged the board too much or if it'll be fine!!