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debs3759

Joined: 18 Jan 2006 Posts: 9477 Location: Northampton, Divided Kingdom
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Posted: Sat Oct 07, 2006 9:07 am Post subject: |
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Wouldn't heating the entire board to 180 degrees do damage to the core if the maximum rated temperature for storage is a lot lower? I tend to think that the extremely fine wires used to connect the core to the poins on any chip will potentially vaporise at a much lower temperature than a lump of thje same metal...
That's why I tend to agree with a heatgun or blowtorch (although a blow torch isn't my preferred option, flames can do more damage than hot air...)
Of course, if a chip is assumed dead in the first place, an oven cannot make it any deader
Mind you, I ahve only recently started considering desoldered chip to be collectible, so I'm sure my opinions on this will change in the close future, as I come across more boards to remove chips from  _________________ My graphics card database can be found at http://www.gpuzoo.com.
I can resist anything except temptation.
Debs |
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chip68

Joined: 19 Oct 2004 Posts: 1024 Location: Central Pennsylvania
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Posted: Sat Oct 07, 2006 10:05 am Post subject: |
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| debs3759 wrote: | | Wouldn't heating the entire board to 180 degrees do damage to the core if the maximum rated temperature for storage is a lot lower? |
No, ICs can withstand quite a bit higher temperatures for brief periods. Aluminum bond wires certainly won't be vaporizing, even with its relatively low melting point compared to other metals. You'd be amazed at what tortures tiny mechanical and electrical components can endure.
- CMW |
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Marcin

Joined: 02 Jan 2005 Posts: 8519 Location: Poland
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Posted: Sat Oct 07, 2006 2:10 pm Post subject: |
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Today I desoldered 286 in PLCC from PCB and cleaned from tin ... it works perfect on other motherboard.
PS. I used heatgun as always. _________________ Visit ABC CPU - Virtual CPU Museum. |
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Root

Joined: 11 Mar 2006 Posts: 64
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Posted: Sat Oct 07, 2006 4:54 pm Post subject: |
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| Quote: | | Wouldn't heating the entire board to 180 degrees |
I heat PCB to temperatures about 280-300°C and I don't have problems. All desoldered chips is working, all boards are in perfect condition  _________________ FreeBSD - forever |
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debs3759

Joined: 18 Jan 2006 Posts: 9477 Location: Northampton, Divided Kingdom
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Posted: Mon Oct 09, 2006 6:48 am Post subject: |
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That's all good to know - it's going to ease some of the stress I have when I desolder chips  _________________ My graphics card database can be found at http://www.gpuzoo.com.
I can resist anything except temptation.
Debs |
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JAC

Joined: 24 Jul 2005 Posts: 3469
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Posted: Mon Oct 09, 2006 6:56 am Post subject: |
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I caught the tail end of a documentary on electronic waste last night on tv.. they showed rows of women in china sat in front of small hot plates. They were placing circuit boards on the hot plates to melt the solder, then removing the components - off all kinds of circuit boards. I didn’t recognise them but there were piles and piles of components and boards of all kinds for stripping and the components for sorting. The workers had no respiratory protection or protective clothing. Some just used their hands.
The hot plate method looked efficient, but about 200 years out of date in working practices. |
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Windmiller

Joined: 24 Jun 2005 Posts: 1716 Location: Chapel Hill, NC
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Posted: Fri Feb 02, 2007 1:53 pm Post subject: |
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Got myself a Grizzly H0801 heat gun and a box of Sun and Apple daughter boards that are in various states.
Our local college surplus is insane, lots of cool stuff. I really wish I new more about some of the old 1960's, 70's and 80's equipment because they seem to have alot of old stuff. |
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Wizzard1

Joined: 05 Nov 2006 Posts: 930 Location: Boston MA USA
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Posted: Fri Feb 02, 2007 6:30 pm Post subject: |
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I do the over method, and also assemble stuff the same way  |
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