x-box 360 PCB Board solder issues - Page 1
Forum section: electronics / repair

author: Johnny10
author_rank: Frequent Contributor
timestamp: December 03, 2015, 05:37:58 pm
content: I am posting an image of the solder joints of my x-box 360.What are the diamond shaped holes marked in red on the pic?

author: Johnny10
author_rank: Frequent Contributor
timestamp: December 03, 2015, 06:42:40 pm
content: And a close-up.

author: Mephitus
author_rank: Regular Contributor
timestamp: December 03, 2015, 09:29:10 pm
content: Looks like a PCB rivet after wave soldering.

author: KL27x
author_rank: Super Contributor
timestamp: December 04, 2015, 12:48:20 am
content: I have never seen a PCB rivet. And I have never seen anything quite like the pic.I would have guessed that those are test points, and the indents were from spearhead pogo pins from the test jig.

author: amc184
author_rank: Regular Contributor
timestamp: December 04, 2015, 10:40:02 am
content: They're blowholes, the moisture content of the PCB was probably too high. The moisture outgasses during soldering and leaves these cavities.Is this an unmolested board, or one that's gone through some sort of Home Style Oven Baked™ reflow process?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 04, 2015, 11:59:14 am
content: Agree, looks like the vias were exposed to wave soldering, but had goo retained or trapped inside the barrel. Goo might be soldering flux, contaminants, moisture*, etc.*Seems unlikely though, vias should seal pretty well. Do they usually have porosity that allows moisture through (from the core/PCB/laminate)? Or is it more a matter of, the PCB material was just that humid, and it had to come out somewhere?There could also be goo trapped from a previous operation (via plugging, or trapped flux that wasn't cleaned -- or no-clean was used(!)) that bubbled on a subsequent operation. As amc184 is hinting at...Tim

author: Johnny10
author_rank: Frequent Contributor
timestamp: December 04, 2015, 01:14:51 pm
content: I am going to check on whether or not this board has been home brew reflowed.

author: Mephitus
author_rank: Regular Contributor
timestamp: December 04, 2015, 07:52:29 pm
content: Quote from: KL27x on December 04, 2015, 12:48:20 amIt's just another way of through hole plating or affixing connectors to a board.

author: Johnny10
author_rank: Frequent Contributor
timestamp: December 05, 2015, 01:21:42 pm
content: The board was never reflowed.

author: SeanB
author_rank: Super Contributor
timestamp: December 05, 2015, 07:17:55 pm
content: That would be gas bubbles in the solder paste escaping. You can see the terst points for the board are the white silkscreen circled holes, and not all have the hole. Thus likely this board was either delayed in production between placement and reflow, or the paste used was a little degraded and had been rejuvenated with extra flux or stirring introducing micro bubbles of air, and this only partly escaped during reflow causing the bursts. You can see as well the non full flow on the pads above the holes, where the solderdid not fully wet the pads, indicating a poor solder paste performance.Probably did pass QC test on the bed of nails, but would have reliability issues down the line.