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timcmi
Joined: 31 Jan 2007
Posts: 3
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 31 Jan 2007 18:44 Is this a cold joint problem? |
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| I am hand soldering a flip-flop 14 pin IC to my circuit board. (Part # CD4013BE). The holes in the circuit board are .033". The circuit functions fine for about 10 minutes and then quits. I probed the pins and get a ground and Vcc at the pin. If I reheat all of the solder joints, the circuit begins to work again....but, after 10 minutes it stops. Any ideas?.....
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VSMVDD
Joined: 12 Jun 2005
Posts: 566
Helped: 55
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| 31 Jan 2007 18:48 Re: Is this a cold joint problem? |
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sounds like your using a cheep solder
thats flux conducts when it gets cold
however a ground on the vcc rail is a direct short
i would check any decoupling caps you have
as heat traveling up a track may be is enought
especialy watch poly layer types
this kind of fault isnt usualy the chip
and is the decoupling cap ....
appart from this look to the solder itself 
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timcmi
Joined: 31 Jan 2007
Posts: 3
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| 31 Jan 2007 19:03 Re: Is this a cold joint problem? |
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| The measured Vcc and ground are on their correct pins. I stated this to show that even though the circuit does not work, These pins are still making a connection. The solder is 63/36/3 fluxless solder.
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Verba
Joined: 11 Apr 2003
Posts: 97
Helped: 7
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| 02 Feb 2007 21:21 Is this a cold joint problem? |
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| Put some flux at the pins of your IC and heat it well, may be they are just dirty a you indead have a cold joint
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timcmi
Joined: 31 Jan 2007
Posts: 3
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| 03 Feb 2007 18:58 Re: Is this a cold joint problem? |
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| The connection problem has been fixed. The solder was not properly bonding to the IC. Flux at the pins as well as a higher heat setting at the iron rectified the problem. Thanks!!!
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