Electronics Forum | Thu Apr 10 08:23:27 EDT 2008 | scottp
If I read you right the issue is mostly with components from one supplier. I'd suggest looking at the components under a microscope. Also, if you have some old pre-tombstoning parts from this same vendor take close-ups of both and compare them side
Electronics Forum | Tue Apr 22 03:46:19 EDT 2008 | fowlerchang
It is CSP reliability issue, which is the mobile CPU from Spreadtrum. All the tests passed and shipped to customer. They assembly them and tested but failed. After they reflow this CSP with hot air gun, some of the boards passed. We got some board
Electronics Forum | Mon Apr 14 16:21:58 EDT 2008 | ck_the_flip
Bottom-side SMT parts CAN and DO go liquidus during the 2nd reflow cycle. It could be that there was enough variability between the 2 different lot code PCBs to cause the parts to fall off. Remember wetting force determines surface tension (the abi
Electronics Forum | Tue Apr 15 21:24:41 EDT 2008 | davef
We find it curious that: * Heat slug pad for Q19 didn't take solder, indicating a pad [board] solderability issue. * Signal termination pads for Q19 didn't flow well, indicating a poor thermal recipe or a pad [board] solderability issue. * Signal ter
Electronics Forum | Wed Apr 16 11:29:31 EDT 2008 | mmjm_1099
Per Tony SMT Here are more photos: Q15, Q16, Q17 represent good transistors on a 1 up board with the transistor locations that are in question. Q13 is a good transistor on a bad 2up board. Right next to it is Q14 a bad transistor on a bad 2 up boa
Electronics Forum | Wed Apr 23 17:40:33 EDT 2008 | dyoungquist
We are a small OEM that also does EMS for local companies. We run our SMT line 10 hours/day 5 days/week and average 2 changeovers per day. We are using a MyData machine in our line. With the proper mix of magazines and feeders, changeover times ca
Electronics Forum | Fri Apr 18 07:50:10 EDT 2008 | scottp
I'm curious if anyone has figured out a clever way to errorproof this. We're exempt from RoHS so we have mostly SnPb products but some Pb free ones at customer request. Of course, we have methods to control moisture sensitive parts, but I worry tha
Electronics Forum | Fri Apr 18 09:16:59 EDT 2008 | samir
Yes, BLAME. It's a common theme in manufacturing unfortunately. Also, unfortunate, is that the PROCESS is the easiest thing to blame and often the path of least resistance to the non-technical manufacturing personnel (operations managers and line s
Electronics Forum | Mon Apr 21 11:55:29 EDT 2008 | realchunks
"Disturbed" usually means some form of movement. I would think your leads are moving due to warp as the board exits the reflow zone. Not knowing your profile, I would suggest checking your profile. Make sure you have adequate "above liquidous" and
Electronics Forum | Wed Apr 23 15:23:16 EDT 2008 | cassedra
I am looking for users of YesTECH AOI that would be interested in comparing notes on what minor problems you have had and how you may have figured out what you could do that didn't require YesTECH support? Or little tricks that help you make the mac
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