KZG caps failed on a NOS motherboard - never been used...

[Lostdotfish]

This is a new one on me. I picked up a new old stock DFI 865PE Infinity board recently. It's completely new, never used. While inspecting it I noticed some unexpected bulging caps...

All of the 6.3v 1500uf caps had failed in place, despite the board never seeing use and being stored sensibly. I pulled the 16v caps that are the same series as a precaution and will replace them all.

[stj]

some types of cap will do that, they generate gas as they breakdown and blow the top or base open.
another thing to watch for, if a cap has not been powered for many years it can on rare ocasions explode when you power it up.
i have had that happen, a sheet of acrylic over the board or safety glasses is a good thing to have.

on the bright side, you can do a polymer upgrade now.
just make sure you match the diameter before ordering.

[Lostdotfish]

some types of cap will do that, they generate gas as they breakdown and blow the top or base open.
another thing to watch for, if a cap has not been powered for many years it can on rare ocasions explode when you power it up.
i have had that happen, a sheet of acrylic over the board or safety glasses is a good thing to have.

on the bright side, you can do a polymer upgrade now.
just make sure you match the diameter before ordering.

Yep, I have some 8mm and 10mm Chemi-Con polymers somewhere that will suit. The irony of using Chemi-Con for this repair is not lost on me...

[Perry Babin]

Plague caps?

[m1ch43lzm]

Yes, you can find old posts on this forum related to Chemi-Con KZG and KZJ caps, like this one:
https://www.badcaps.net/forum/genera...zg-s-still-bad

The consensus here is: KZG = Replace on sight, no questions

[Lostdotfish]

That's better. Uprated the 6.3v caps to 16v since they were the ones that fitted.

The via stitching/thermal reliefs around the positive legs (little flower shapes you can see in the unpopulated positions) sure sunk a lot of heat... Using leaded solder and my 700 fahrenheit tips (370 C) and they were still tricky to clear and then get the new joints to wick in properly. This is even with my Metcal station and tips that will solder pennies to car doors...

[stj]

i pre-heat the board first with hot air.