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Let’s take it apart

A7N-8X Capacitor Replacement


From the late 1990’s through the early 2000’s there were a bunch of motherboards (and probably other electronics) manufactured using electrolytic capacitors with rather undurable electrolyte. Assuming you throw your technology away after two years, this isn’t a problem. But I don’t; I try to wring the last bit of useful out of hardware.

Such is the case with this A7N motherboard. I purchased this guy to replace an A7V that completely died. I eventually replaced this board with an Intel board because of some software requirements, leaving this one sitting idle for awhile. I recently pressed it into service running FreeBSD and acting as a file server and my gateway to the interwebs.

I wasn’t actually having any problems with this board but I have had boards in the past which failed because of bad capacitors. I decided that rather than wait until these failed completely, I would, since I had replacements on hand, go ahead and replace them.

Bulging tops and orange powder from leaking electrolyte are pretty good indicators that these aren’t doing their job. To do the replacement, I just heated the leads from the bottom one at a time and rocked the capacitors out. This is not a particularly easy thing to do since the holes in the board are through-plated and connect to substantial amounts of copper in the board, so it takes quite a bit of heat to get the solder to melt. After I’d pulled all of the capacitors out, I tried to use some solder wick to clear out the holes with very little success. Without purpose-built equipment, it is pretty hard to coax the solder out of the holes.

Instead, I used a small drill (about 0.021″) to mechanically clean out the holes. The solder left in the holes formed a cup, making it pretty easy to (CAREFULLY!) drill out. It does take a very small bit – I’d recommend a bit only as large as you needed to get the leads of the new capacitors through.After drilling out the holes, I soldered in the new capacitors and cleaned off the leftover flux with a toothbrush and some acetone. The board works like a champ.

I got the capacitors from DigiKey, 493-1256-ND: 3300uF, 6.3V

You’ll need to get the quantity and values for your specific board if you decide to go this route.

posted under RepairIt

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