A detail on the back side of Enermax Revolution85+

[Travis]

http://www.ocer.net/article/a_show.php?id=17881

Internal shot, front side
http://www.ocer.net/article/a_upload...081223-8-0.jpg

Internal shot, back side of the PCB
http://www.ocer.net/article/a_upload...0081223-20.jpg

The soldering isn't good but isn't bad either. My concern is the two diodes added on the back of the main transformers -- anode connected to ground, and cathode connected to the secondary pins of each transformer. They're "clamping" the secondary negative voltage.

It's a patch for a certain design defect on this platform. I remember Revolution85+ uses synchronous rectification on secondary side?

[SnooP]

Diodes only held by solder too, not part of the pcb design, added by hand. yuck! My guess is that'll raise some QA issues

[Smirnoff]

But the big question is... Will it explode? :-O

[jonnyGURU]

Originally Posted by SnooP

Diodes only held by solder too, not part of the pcb design, added by hand. yuck! My guess is that'll raise some QA issues

Right, but they probably had to do it after the fact to address some other QA issue.

[Super Nade]

Soldering is horrific for a premium product. Odd place for the diodes. You'd expect to see them on the secondary side as part of a snubber.

[Spectre]

That looks like one of the first revision samples engineering samples I got except for the bar coded transformer. The very first didn't have anything on the transformer. Second revision had bar code no diodes. Serial production model had bar codes, diodes, but the solder wasn't done by hand and they had some sort of binding agent on them.

Hey, and I have seen worse soldering out of Topower

[Travis]

My opinion is these diodes clamp the peak negative voltage on the secondary side. Maybe for a better efficiency Enermax has to use secondary MOSFETs with lower reverse voltage(and lower Rds-on) but with that the negative peak voltage would be too dangerous for these MOSFETs, so they added these snubbers -- yup, by hand.
It's ugly but perhaps it's necessary.