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 Post subject: Soldering IC Chips
PostPosted: Nov Wed 23, 2016 9:35 pm 
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Joined: Jan Sat 12, 2013 7:14 pm
Posts: 1142
Location: Plymouth, Michigan
Sort of new to the IC scene, I always considered it a passing phase....
I'm going to be making a shop AM radio with the ZN414 RF chip, and a LM386N-4 audio chip. I can get a socket for the 386, but the other is a three lead chip, strongly resembling a standard transistor. I'm using a Weller WE-51 station, and was wondering what you all do for a heat sink. Will a regular alligator clip, or a pair of hemostats suffice? These aren't expensive chips, but I would prefer not to ruin them if I can help it.

Thanks for any advice!

Pete

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 Post subject: Re: Soldering IC Chips
PostPosted: Nov Thu 24, 2016 1:08 am 
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Joined: May Sat 25, 2013 11:15 pm
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Location: Central Iowa, USA
Yeah, an alligator clip should work just fine. I have never wrecked an anything when soldering that way.

Rob


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 Post subject: Re: Soldering IC Chips
PostPosted: Nov Thu 24, 2016 2:48 am 
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Joined: May Tue 30, 2006 4:46 pm
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Location: Santa Rosa, CA
ZN414s are pretty rugged. Use an alligator clip. I have never killed one.

Recently used some SIP headers to make a 3-lead socket.

http://theradioboard.com/rb/viewtopic.php?f=4&t=7310

Rich


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 Post subject: Re: Soldering IC Chips
PostPosted: Nov Thu 24, 2016 2:25 pm 
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Location: Plymouth, Michigan
Thanks guys!

Pete

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 Post subject: Re: Soldering IC Chips
PostPosted: Nov Fri 25, 2016 2:32 am 
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Location: Boiling Springs, PA
Most plastic packaged semiconductors dont conduct heat well through the plastic and attaching a heat sink to the leads usually makes soldering more difficult as it draws heat away from what youre trying to solder. Best practice is to keep your iron to the lowest setting for the solder youre using and keep the time short on each lead. Use the lowest power iron needed for the work and use a fine tip as it wont heat the leads as quickly or as much as a chisel tip. Figure that most all through hole (DIP) packages assembled in factories go through a wave solder process where they are dipped in a molten solder bath for a fair period of time and rarely are there actual failures from it. Surface mount parts go through a hot air tunnel where the entire part is heated with a hot air blast to the solder melting point for a period of time. (technically they go through twice, once for each side of the PCB) To make matters even more interesting, lead free solder has a higher melting point than 60/40 so that is even worse in many respects. I know thats more detailed than you are looking for but it puts it in perspective.

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 Post subject: Re: Soldering IC Chips
PostPosted: Dec Thu 01, 2016 1:36 am 
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Joined: Jan Tue 31, 2012 2:17 am
Posts: 198
Location: Hamilton, ON, CA
I use a 27W iron with a fine pencil tip, no alligator clip, about one second is all it takes on each of the pins. If doing a large one, I'd give it a break after a few pins if there's any concern.


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 Post subject: Re: Soldering IC Chips
PostPosted: Dec Thu 01, 2016 2:55 am 
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Joined: Jun Sun 12, 2011 1:32 am
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Location: Middle Tennessee
From time to time I build stuff from scratch. Many times I just use a socket and solder that to be safe. Then plug in the chip after I am done. No heat worries.


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 Post subject: Re: Soldering IC Chips
PostPosted: Dec Sat 03, 2016 11:01 pm 
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Posts: 4219
Location: Los Angeles
willy3486 wrote:
... use a socket and solder that to ... plug in the chip after I am done ...


+1 for sockets. Great for hobby projects, with only a few ICs. Also good for debugging, as you can lift out a pin, or two, without using your soldering iron.

That said, modern silicon ICs are pretty robust. I routinely solder ICs with as many as 44-pins (surface mount), with little concern. More worried about static, so I wear a grounded wristband, and do it on my static free work station. I use a Weller WP25 (25W) with the smallest tip made for that iron. Actually the temperature is rather hot, but its concentrated in a small area. You want the solder to melt, and "wet" quickly, so you're not transferring a bunch of heat to the IC. Time is your enemy. Keep it short, so make it hot, fast. Though, don't use a 100W American Beauty :shock:

I think the lead heatsinking idea is a hold over from the germanium days. Silicon semiconductors are much more heat tolerant than germanium. There were still a lot of germanium transistors floating around the hobby scene well into the 70's.

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 Post subject: Re: Soldering IC Chips
PostPosted: Dec Sun 04, 2016 4:55 pm 
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Joined: Feb Sat 12, 2011 2:29 pm
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Location: Fayette County, Pa
I never worry about heat on I.C.s Rather I concentrate on making sure everything is clean and ready to accept solder. Then use low heat heat as possible with a small tip. If everything is good you can do a connection in under a second so heat never builds up on the IC. You can also use electronic solder flux to aid in flowing the solder. CAREFUL THOUGH, make sure it is for electronic use, NOT the acid flux used for plumbing applications! That stuff will corrode the circuits. Then do a thorough cleaning of both sides of the board after you have finished soldering.

Except in cases where I may want to change chips frequently (An EPROM is an example of that, I may want to alter the programming!) I don't use sockets as they introduce another point of failure. (Dirty contacts or oxidation on the IC pins that make poor connection). I solder everything right to the board where possible.


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 Post subject: Re: Soldering IC Chips
PostPosted: Dec Thu 08, 2016 10:48 pm 
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Location: Tennessee 38058
+1 for sockets, when possible. Good quality sockets, that is...

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 Post subject: Re: Soldering IC Chips
PostPosted: Dec Fri 09, 2016 7:11 am 
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Location: SoCal, 91387
I managed to ruin a few CK722's back in the day, but with modern components + me knowing now halfway what to do, soldering directly to the leads is NP.
I have a 70 watt Weller, and have made two TRF's using ZN414's directly soldered into the circuit.

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