Hi,
Really a question out of curiosity more than anything else. Today I was messing around with a piece of hi-fi which had a faulty internal PSU and wanted to change it for a spare and to do this I needed to swap a 4 core connecting cable which was soldered into the PSU.
I first tried unsoldering the cables using a small electronics specific soldering iron which I think is 60 to 75 watts - the type with a conical point. The solder just didn't want to melt so tried my Weller soldering iron which is probably a couple of hundred watts. Again couldnt get the solder to melt even though the cable was getting too hot to hold where I was gripping it a few cms from the joint and the sheath was almost melting!
Playing with circuit boards is not something I do very often, so maybe my technique was wrong, but as I said there were 4 wires and not one came out easily, even using the Weller. So curious as to whether some manufacturers might use higher melting solder?
Any comments appreciated.
Alchad
Really a question out of curiosity more than anything else. Today I was messing around with a piece of hi-fi which had a faulty internal PSU and wanted to change it for a spare and to do this I needed to swap a 4 core connecting cable which was soldered into the PSU.
I first tried unsoldering the cables using a small electronics specific soldering iron which I think is 60 to 75 watts - the type with a conical point. The solder just didn't want to melt so tried my Weller soldering iron which is probably a couple of hundred watts. Again couldnt get the solder to melt even though the cable was getting too hot to hold where I was gripping it a few cms from the joint and the sheath was almost melting!
Playing with circuit boards is not something I do very often, so maybe my technique was wrong, but as I said there were 4 wires and not one came out easily, even using the Weller. So curious as to whether some manufacturers might use higher melting solder?
Any comments appreciated.
Alchad
i'm just a noob my self
very old solder can be difficult to melt, maybe next time try adding some new solder and then solder wick it back out with hopefully some of the old as well.
very old solder can be difficult to melt, maybe next time try adding some new solder and then solder wick it back out with hopefully some of the old as well.
Likely to be RoHS (no lead) solder. Try adding a little 63/37 solder as you heat the joint.
Usually it's easiest to cut the wires an inch from the board, and remove each individually.
Usually it's easiest to cut the wires an inch from the board, and remove each individually.
Possibly a varnish layer? Sometimes it is hard to unsolder an old soldering joint so I apply an alcohol rosin first. It always help a lot.
Do you have bigger, flatter tips like chisel tips? Conical tips have a very small surface of contact. Regardless of wattage/heat retention, a small surface area will always transfer less heat than a big tip.
Additionally, hold your tip close to the joint, add solder to your tip (yes) and then take it to the joint and add more solder. This should help the solder from the joint and the soldering tip bond at first; and once this first bond is made the heat transfer is tremendously better. This works because the tip has some of the flux if you're fast enough, and flux cleans oxidation.
if you can't get this solved, post a picture!
Additionally, hold your tip close to the joint, add solder to your tip (yes) and then take it to the joint and add more solder. This should help the solder from the joint and the soldering tip bond at first; and once this first bond is made the heat transfer is tremendously better. This works because the tip has some of the flux if you're fast enough, and flux cleans oxidation.
if you can't get this solved, post a picture!