Hi Scott, I'm soldering SMDs onto newly made PCBs (my own design, for some new boards of my selfbuilt 6502...) The PCBs got solder resist (solder mask, Lötstopplack) on them, I didn't trust myself enough to not use it... I did solder the other ICs with 1.27mm pin distance (74xxx logic, RAM) with a small soldering iron and small solder and it worked fine. Even with traces running between the pins. I did use a magnifying glass though... :-) (and some desoldering braid(?) to get superfluous solder away). Only the other ICs I have are even smaller. I'm new to soldering with flux, but it seems I'll have to give it a try. Thanks for your advice! André -------- Original-Nachricht -------- > Datum: Sun, 1 Nov 2009 07:27:52 -0500 > Von: "Scott" <rylos@charter.net> > An: cbm-hackers@musoftware.de > Betreff: RE: SMD soldering? > Andre' > > Make sure the glue that held down the old IC is removed, you can do this > by > over curing it with your soldering Iron. Then prep the pads, use flux and > leave a small amount of solder on the pads. This solder will make the > joint > for you. > > I then tack down opposites corners of the IC using just enough solder on > the > iron to make it conduct. If the IC's pins are not bent most of the other > legs will fall in place. If they don’t, carefully move them over with a > sharp pointed object, I usually use an Explorer (dental tool). > > Once you have everything aligned. Soak the pins will a good flux. I still > prefer rosin flux because no clean evaporates too fast. Now, hold the pin > down with the Explorer and touch it with your Iron. If you have enough > flux > on the leads you shouldn’t have to worry about bridging the pins. So > don’t > be overly concerned about touching more than the leg you want to solder. > > Once everything Is tacked down, clean then reapply flux and re-solder > using > the explorer to get that clean finish. Then take the explorer or exactor > knife and carefully run it between the legs of the Ic to make sure there > are > no bridges. Observe with a magnifying glass. Clean again and your done. > > Of course make sure you bounce back and forth when soldering, left side of > the chip to the right side, this way you won't overheat the IC. And most > important, your Soldering iron tip temperature should turn to a nice > golden > brown after solder is applied. If it turns the flux in the solder black > then > you are way to hot. > > Anyway, all steps are important. But To answer your question, I normally > just tack down the corners first. > > -----Original Message----- > From: owner-cbm-hackers@musoftware.de > [mailto:owner-cbm-hackers@musoftware.de] On Behalf Of "André Fachat" > Sent: Sunday, November 01, 2009 06:31 > To: cbm-hackers@musoftware.de > Subject: SMD soldering? > > > Hi, > > I know some of you do SMD soldering. I did already solder 1.27mm distance > packages, but now I have to solder some 1.0 or .8mm pins - and I find it > quite difficult to position the SMD part correctly. I only have normal > pincers as help. I solder one pin and by resoldering that pin I can > actually > correct the position before soldering the other pins - but that seems > difficult with those smaller parts. > > What do you use to position those SMDs? Do you have vacuum pincers / > airpicks (or whatever they are called)? Or do you use other tools? Like > glue > to keep the part in position when positioned? > > Any help appreciated > > Thanks > André > > -- > GRATIS für alle GMX-Mitglieder: Die maxdome Movie-FLAT! > Jetzt freischalten unter http://portal.gmx.net/de/go/maxdome01 > > Message was sent through the cbm-hackers mailing list > > > --- > avast! Antivirus: Inbound message clean. > Virus Database (VPS): 091031-0, 10/31/2009 > Tested on: 11/1/2009 6:38:35 AM > avast! - copyright (c) 1988-2009 ALWIL Software. > http://www.avast.com > > > > > > --- > avast! Antivirus: Outbound message clean. > Virus Database (VPS): 091031-0, 10/31/2009 > Tested on: 11/1/2009 7:27:53 AM > avast! - copyright (c) 1988-2009 ALWIL Software. > http://www.avast.com > > > > > Message was sent through the cbm-hackers mailing list -- GRATIS für alle GMX-Mitglieder: Die maxdome Movie-FLAT! Jetzt freischalten unter http://portal.gmx.net/de/go/maxdome01 Message was sent through the cbm-hackers mailing listReceived on 2009-11-01 13:00:14
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