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March 2012

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Subject:
From:
Paul Edwards <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Paul Edwards <[log in to unmask]>
Date:
Wed, 7 Mar 2012 17:11:28 -0800
Content-Type:
text/plain
Parts/Attachments:
text/plain (160 lines)
Interested in both sets of photos...

I would appreciate a getting those...

Paul

Paul Edwards
Process/Quality Engineering
Surface Art Engineering


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Goodyear, Patrick
Sent: Wednesday, March 07, 2012 12:50 PM
To: [log in to unmask]
Subject: Re: [TN] Damaged board traces,

They have been stored in the seismic card cage of a spare chassis in an environmental storage room for the most part.  Not sure about how they were trimmed originally, by looking at the cut ends of some of their brethren they appear to have be sythe sheared after soldering with some sort of rotary tool and not a flush cutter per se.   These were made in the late 60's early 70's when 300 watt solder guns were the norm and horse hoof nippers were about the closest one got to flush cutters.   Anyhow thanks for the ideas, will repair the damage as we require everything installed to be 100% inspected to 0 defects.   I actually found one of the cards with the soldered leads on a strapped SCR that were stress cracked, keep in mind these cards have only seen power for short periods, hour or two max, maybe 3 times in 40 years, no test records were found.  Thought the group mind find them interesting.   

I have numerous photos of failed solder joints and tin whiskers in case anyone is interested. 

pat

   

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Wednesday, March 07, 2012 12:09 PM
To: [log in to unmask]
Subject: Re: [TN] Damaged board traces,

Okay, 'net is back up. Here are the photos:

http://stevezeva.homestead.com/tracedamage_1.JPG

http://stevezeva.homestead.com/tracedamage_2.JPG

http://stevezeva.homestead.com/tracedamage_3.JPG

http://stevezeva.homestead.com/tracedamage_4.JPG

It looks kinda' like maybe someone wasn't being careful when they were trimming the leads quite possibly. I've seen nicks in soldermask from someone trimming leads and letting the point of the cutters come into contact with the board as they were trimming them.

Or can I ask how the boards were packaged during the last 40-years? Were they packaged individually, or could it have been that they were packaged back-to-back in pairs and the damage that you see on the traces is from the leads of the other board? The little gouges look about the same size as a lead...

Steve
 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of steve gregory
Sent: Wednesday, March 07, 2012 2:24 PM
To: [log in to unmask]
Subject: Re: [TN] Damaged board traces,

Well, I was going to post them, but we've lost our internet here at work...

Sent via BlackBerry by AT&T

-----Original Message-----
From: Steve Gregory <[log in to unmask]>
Sender: TechNet <[log in to unmask]>
Date: Wed, 7 Mar 2012 12:12:09
To: <[log in to unmask]>
Reply-To: TechNet E-Mail Forum <[log in to unmask]>,
        Steve Gregory
	<[log in to unmask]>
Subject: Re: [TN] Damaged board traces,

I've got them Pat, positing shortly...

Steve

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Goodyear, Patrick
Sent: Wednesday, March 07, 2012 11:58 AM
To: [log in to unmask]
Subject: Re: [TN] Damaged board traces,

 the mail server stripped the attachments, where do I send them?

pat

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Goodyear, Patrick
Sent: Wednesday, March 07, 2012 8:20 AM
To: [log in to unmask]
Subject: Re: [TN] Damaged board traces,

Rubs are definitely mechanical in nature.   The leads are not clinched.
Here are a couple of pictures.  

pat 

-----Original Message-----
From: Steve Gregory [mailto:[log in to unmask]]
Sent: Wednesday, March 07, 2012 4:58 AM
To: 'TechNet E-Mail Forum'; Goodyear, Patrick
Subject: RE: [TN] Damaged board traces,

Wow! 40-year old boards and it's the first time they're being used...I guess they really are what you would call legacy boards.

Are the leads clinched? Although I don't think it is something with auto-insertion equipment, but you never know. Can you take a couple of pictures?

Steve

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Goodyear, Patrick
Sent: Tuesday, March 06, 2012 5:34 PM
To: [log in to unmask]
Subject: [TN] Damaged board traces,

Working on single sided legacy boards, I finding half moon rub marks on the
traces adjacent to pads, about 0.15" (3.5mm) away.    They are  circular in
nature (half moon shape) on the edges of the traces.   Definitely
mechanically made.   These boards are roughly 40 years old and have never
been used.  I'm inspecting them prior to installation.
Anyone know of any OLD process that could make these types of marks.  I have inspected 4 boards and find the same types of deformation on all of the boards although not in the same places.

   I suspect the boards were originally hand soldered, as there is no solder mask on the runs and they are plated with no excess solder clinging to them.

   pat


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