Warning: You probably shouldn’t read this, if you have a queasy stomach, or are sensitive to talk about dead creatures.

A few months ago, I came home, and I found the house had no power.

A check of the power meter showed that the earth leakage circuit breaker had tripped. I flicked the switch to reset it. But after a few seconds, it trips again.

By process of elimination, I narrow th problem to an old (pentium 2!) PC in my workshop.

I open up the PC, and I find ants, cockroaches, and geckos… YUCK! I see some yellow stains (that once were liquid).

I brush out all the animal life, spray the ventilation holes with insecticide, and set some cockroach baits around the workshop (which worked very well).

I try the PC again, and it now works fine. I put everything back in its place.

About 2 months later, the same thing happens (no power… the same PC is shorting out).

I open it up again, but this time it looks clean.

I start to dismantle the power supply, thinking its probably dead. As I pry open the PSU case, I see a large gecko inside 😮

I drop the PSU outside, on the grass, and the gecko leaps out.

I then finish taking off the PSU cover, and as I peer inside, I can see a headless gecko body across the 240 volt power terminals :-s

I carefully remove the “short” (REMEMBER: working inside a power supply can be deadly. Don’t do this unless you know what you are doing!). I also carefully look over the rest of the PSU, and I find 2 dead cockroaches (I remove one, the other is inaccessible, so I leave it). I also find the head of the “fried” gecko (at the other end of the PSU!)… Looks like it literally got it head blown off…

Anyway, I reassemble everything, and the PC is working again.

Now, the reason the geckos got into the PSU is: the PSU fan is a “push” fan: Its inside the PC case, and it pushes air through the PSU. Most PSUs use pull fans (the fans pull the air through the PSU, so that the fan is the last device before the air gets outside the PC case).

So, the ventilation holes at the back of the PC/PSU are a little larger than normal, they are rectangular, and there is no fan directly behind them. A perfect home for a wandering “lizard”.

How do I stop this from happening again?

I was thinking extra wires to make the ventilation holes smaller, but it was going to be messy. Then Mandy had a great idea: Use packing tape to totally seal the holes, then poke some holes into the tape. I can now choose how many holes, and their size… perfect!