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RE: [N8VEM-S100:2216] Interest, Discussion and R&D on a 18 Slot S100 Backplane & ATX PSU board.



Hi Vince,

That's an interesting way to do it.  But you are going to need the find the right heat (you made that clear).
I have in the past used a propane torch, it totally wrecks the board but heats the solder faster than the IC's can get even warm.  I guess it depends if there are a lot of via's or other holes.  About 20 years ago, I bought a professional PACE desoldering station, it works great.  You can get them very cheap these days.
But ultimately, the *BEST* way to remove these components would be a solder pot.  You can probably even make your own with that heat gun and some sheet metal.  If you want to get fancy, you could get an old stove element and fit it into the pot yourself. 

Needless to say, Safety first.  Use gloves and long pliars, a vise or other board holder.  Do not run fire indoors for extended periods without proper venting (Carbon monoxide),  A fire extinguisher is probably a good idea, but a bucket of cold water is more useful in case you get burned.  It really helps to run your burn under cold water.  Finally, don't drink liquid solder.  It may look delicious in the pot, but it burns all the way down.

Regards,
Josh




Date: Mon, 6 Jan 2014 14:35:48 -0800
From: vincemu...@gmail.com
To: n8vem...@googlegroups.com
CC: norwe...@aol.com
Subject: Re: [N8VEM-S100:2216] Interest, Discussion and R&D on a 18 Slot S100 Backplane & ATX PSU board.

On Monday, January 6, 2014 3:20:46 PM UTC-6, norw...@aol.com wrote:
Just curious ... how do you go about removing an S-100 connector (to get a "used" connector) that has been soldered into the backplane without destroying it .... and the backplane????  Is specialized equipment needed?

Yes specialized equipment, good news is its only like $5.  Take a heat gun with straight tube, cheapest Chinese ones won't last long enough to desolder one connector, an all metal high temp preferably all stainless steel hose clamp (emergency car muffler repair ones are pretty good, partially plastic garden hose clamps won't work) and some sheet metal and make a diffuser that looks very much like the paint stripper diffuser but big enough to cover the entire SMD chip or in this case a S-100 connector.  It'll look like a SMD hot air rework nozzle except this one is big enough to hold an entire S-100 connector.

Low air flow high heat (this burns some cheap hot air guns out).  Some heat guns get hot enough to burn the board.

Barely hot enough + loooong time heating (like minutes) means massive melted plastic damage.  Really hot + 10 seconds means you've pulled it off the board before the plastic starts melting, before it "knows" its being desoldered its already been removed and is cooling off.

In the early-mid 80s, back when 41256 chips cost an awful lot, I turned a giant, broken, multi-thousand dollar voicemail board into 512K upgrade on my computer at the time, of course these were DIPs not S100 sockets, but my homemade nozzle worked pretty well.

The nozzle gets pretty hot, obviously well over liquid solder temp, easy to get a burn.  Also if you carelessly set down the heat gun you can set a wooden picnic table on fire.  So that's what I learned the hard way 30 yrs ago.

Needless to say this violates every possible warranty and freaks out the local fire marshal and EPA official and keep kids away etc etc.

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