SMPS corrosion, destruction & teardown - Page 1
Forum section: electronics / projects

author: billclay
author_rank: Regular Contributor
timestamp: June 27, 2013, 08:33:28 pm
content: I've had many (>25 so far this year!) power supply failures for blade servers in a datacenter. This datacenter has hadMANYhigh humidity events.There is evidence of via (green) corrosion near where the catastrophic damage occurred around the Infineon 35N60C3 power transistor and D06S60C schottky diode.The input fuse (F100) is open, and the copper traces are blown off the board due to these parts shorting.You can see there is a white substance all over the board, components, wires, just about everything. I've heard of water-soluble flux residue attracting contamination in high humidity envornments, but I don't think this is just flux.There seems to be a pattern to the contamination as well. It may be following the magnetic flux lines on the PCB? Or possibly the airflow from the fans?Here are the rest of the photos:http://www.flickr.com/photos/18144341@N00/sets/72157634358342559/What is happening here?

author: bilko
author_rank: Frequent Contributor
timestamp: June 27, 2013, 09:46:17 pm
content: I can't believe that this is just flux residue and manufacturing QC, re the PSUs. I would look at the climate control system in the facility and check the filtration system. There appears to be lots of airborn pollution entering the equipment. The high humidtiy events will cause it to stick to the surfaces as hot moist air condenses on cool surfaces.Quick check, remove the facilities air conditioning filters and inspect.Is the site near an industrial area, chemicals, marine environment, because moist salt laden air destroys electronics

author: billclay
author_rank: Regular Contributor
timestamp: June 28, 2013, 12:02:15 am
content: Quote from: bilko on June 27, 2013, 09:46:17 pmIt's not near a marine or industrial environment. I do think they are using open-air cooling though.

author: Rerouter
author_rank: Super Contributor
timestamp: June 28, 2013, 02:56:05 am
content: that looks like larger clumps than i'm used to seeing, but it looks just like the digital gauge pcb's i repair in buses that leak like sieves, on my side i think its mainly dissolved salts and chemicals in the air follow the water in and when the rain stops those little white spots form, so being its open air cooling quite possible its a similar problem,

author: SeanB
author_rank: Super Contributor
timestamp: June 28, 2013, 08:20:56 pm
content: Definitely you need to look into getting some HEPA filters on the air inlets there, along with possibly an electrostatic precipitator followed by another HEPA filter to remove the dust and fine suspended particles from the filtered air before it goes to the air handler, and have a humidifier to keep RH constant. I work about 100m from the sea, and only the outdoor units suffer from such salt corrosion problems. You must try to keep your data centre or server room at a positive pressure and keep the doors, cable ways and such closed and provide a controlled air vent so that you have positive air keeping the contaminants out. You will probably have to clean all the equipment after stripping it to get it out of the circulating air, and have another set of HEPA filtering there as well.

author: billclay
author_rank: Regular Contributor
timestamp: July 15, 2013, 09:29:35 pm
content: Unfortunately, I'm not the owner of the datacenter. I'm only a customer, so I can only make "suggestions".To make this even more puzzling, this fine particulate matter also attaches itself to the power cables. None of the fiber or low voltage copper have this contamination on it. It attaches to the cable exterior above the Line and Neutral conductors. There is none over the Ground conductor.I've never seen anything like this.

author: komet
author_rank: Unknown
timestamp: July 15, 2013, 09:52:43 pm
content: If you're a customer then there should be a contractually defined humidity, e.g. 30% to 50%, and if they are outside that you should be getting a refund. Otherwise get a better data centre.