Peter,
it's strange with those corner ball problems. We have seen same. Somebody at TN, forgot who, had the idea that wide traces to ground or power, traces on top speaking, will act as kind of heatsinking and you'll get some lower than average temp exposure to those balls. In our case, the cracks didn't occur at the BGA interace but at the PWB side. Your pictures are interesting to many I guess, but what about the heatsinking theory? Other go more for Biunno's battery effect.
The okie man, being head guru (at least best in show, he-he) at TN now, has the answer already?
Ingemar
-----Original Message-----
From: <Peter George Duncan> [mailto:[log in to unmask]]
Sent: den 29 mars 2001 08:06
To: [log in to unmask]
Subject: Re: [TN] BGA crack pic
I noticed the big fat track too, but as it runs right through the ball next
door, and that ball is said to be OK, I took it that it had no effect on
our faulty friend. I asked Rudolph if he had any other microsection
pictures of the surrounding balls for comparison, in case this is another
example of BGA's 'shady tree' effect, as I call it, i.e. the balls sitting
under such a large parasol don't get the heat they need to reflow properly.
Best regs
Pete Duncan
"Stephen R.
Gregory" To: [log in to unmask]
<SteveZeva@AO cc:
L.COM> Subject: Re: [TN] BGA crack pic
Sent by:
TechNet
<[log in to unmask]
ORG>
03/29/01
11:20 AM
Please
respond to
"TechNet
E-Mail
Forum.";
Please
respond to
SteveZeva
Rudolph and everybody,
Go to:
http://www.xdrive.com/share/985835366039lhSi4tEHHweAj9vYGZA6
Good pictures Rudolph! Only thing I notice right away is that big fat trace
next to the ball that's failing...is the same pattern with this device on
the
other boards that you say uses this same asic?
-Steve Gregory-
<< Steve:
Thanks for putting this up for me. So you will let me know the URL
address?
Thanks again
Werner, Peter, Hector:
Thanks for the inputs!!
Rudolph >>
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