"Ian Field" wrote in news:gdzNr.12270$ snipped-for-privacy@fx05.am:
if you sucked out the applied solder,there's probably little leaded solder left to "harm" anyone. maybe not even detectable with their usual tests.
And I'm not going to tell on you. :-)
-- Jim Yanik jyanik at localnet dot com
"Ian Field" wrote in news:IjzNr.11534$ snipped-for-privacy@fx07.am:
ACH,the HORROR!!!!!
-- Jim Yanik jyanik at localnet dot com
Yep, but I don't do it that way. With SMD, the problem is identifying the parts after they've been removed. I usually just want the active components anyway.
***One thing I particularly go after is the larger multilayer SMD chip capacitors, surprisingly large values in surprisingly small package. Also the larger discrete semiconductors, the TO251/252 fit less veroboard space than a TO92."Ian Field" wrote in news:IjzNr.11534$ snipped-for-privacy@fx07.am:
ACH,the HORROR!!!!!
***WEEE wasn't even a glint in someone's eye back then - thousands of those sets went to landfill with the roll of cadmium solder untouched.***Round about WW2 time - ish; component leads weren't tinned - they were cad plated.
It's done all the time, but you have to 'reball' the chip first. Then it's exactly like using a new part. Military & medical have to have the lead free crap repalced with real solder balls. You can buy the balls and simple tooling on Ebay for very little money to reball them yourself.
And take out part of the via (your 'hole') in the process? A board with damaged vias would be scrapped at the factory.
It probably is lead-free solder. Dilute the solder with tin-lead solder, which will lower the melting point. Then, use a solder sucker, solder wick or what have you to clear the hole.
Jon
True. It's NOT easily done. I've only tried one large BGA chip and it didn't work. However, I've successfully replacing two smaller BGA wireless chips. Instead of reballing, I used solder paste on both the chip and the PCB. Then reflow with a hot air desoldering station. Here's the general idea:
except that I used solder paste instead of trying to make solder balls on the BGA chip. Note the copious use of (paste) flux. (Incidentally, the cell phone is a Qualcomm QCP-6035).
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
(...)
I've never tried the stuff. The problem is that dross (oxidized solder) will not flow, wick, or can be easily blown through the hole. All that's really needed is some 60-40 and a little flux. Once the dross is gone or disolved, the solder should flow and the hole clear easily. Chip-Quik sounds like an interesting way to do a whole IC at once, but I have a hot air desoldering station that works.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
Bad idea. That usually rips out the plating in the hole. The drill collects a mix of solder and copper around the outside, which galls together with the solder plating inside the hole, and eventually rips out the plating. Even if you can find a workable drill, keeping the drill exactly perpendicular to the PCB is quite difficult.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
Bad idea. That usually rips out the plating in the hole. The drill collects a mix of solder and copper around the outside, which galls together with the solder plating inside the hole, and eventually rips out the plating. Even if you can find a workable drill, keeping the drill exactly perpendicular to the PCB is quite difficult.
***I'm with those against drilling - maybe with a drill bit *MUCH* smaller than the hole, but if the cutting tip hits a hard obstruction it'll take chunks out of the through plate wall in preference.
you must be careful to not remove the vias conductor when doing so.
Jamie
That's exactly what I ended up doing. I was not using a pick to clear the hole, but only to test it. I have a Pace vacuum station, but it doesn't get hot enough for lead-free even when mixed with 60/40.
-- Reply in group, but if emailing add one more zero, and remove the last word.
From someone in a high-reliability RoHS derogated industry, it is quite a work-up to test for elemental lead on the "tinning" of component leads. Their problem is false-manifest/specced components that are bought supposed to be the now expensive leaded tining , actually being now-standard PbF components and fraudulently traded.
you must be careful to not remove the vias conductor when doing so.
Jamie
***Easier said than done!
I have a tip I made for my Hot air wand that has a hypodermic needle on it. I heat it up and hit the air switch and push it through the hole.
Jamie..
What is that like with PbF ?. Hypos use stainless steel and I find stainless steel is a reasonable identifier of PbF as it determinedly sticks to stainless steel, does the capilliary bore of the needle then totally block with solder?
I have a tip I made for my Hot air wand that has a hypodermic needle on it. I heat it up and hit the air switch and push it through the hole.
Jamie..
***Many years ago I made an SMD harvesting machine out of a portable LPG heater and an old fridge compressor.***The copper pipe was coiled and stuffed behind the guard on the heater, right in front of the burners. A carburetor jet was peened into the end of the copper pipe to produce a fierce jet of very hot air.
***A cardboard box on its side opposite the nozzle caught most of the low flying SMDs, but I had to abandon it because it was just too hot sitting so close to the heater.
According to what he wrote he is forcing hot air through the needele, so solder can't get inside it.
you have your air pump when when doing so. No, it does not stick to the needles I use. In fact, I can just shake it and the solder will fall off.
Jamie
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