[luka]

Just a small warning story how a 99% finished DIY project almost turned into a disaster because of my laziness to do the final step.

About 6 months ago I built a cold-finger cooling for my Canon 450D. The camera modification was done and I finished a custom-built TEC controller (using microcontroller for PWM). I was just finalising the last part which was the cable when I realised that I did not have a connector that can carry enough current (5A). The local shop was closed and I had to try it out right then... so I figured out that it is winter and cold so that the TEC won't be running at full power and that I can use a lower rated 3A connector... only for a quick test and I'll be monitoring the temperature at all times...

Everything worked great and the connector did not even get warm (PWM was under 40%). So I tried the DSLR at night and it worked beautifully. Again no heat on the connector... and again the next night and so on. I kept telling myself to replace the connector but there were other things to do and build... eventually I forgot.

Fast forward 6 months to a hot summer Perth night and TEC running at almost full power. I was messing with the guiding for a long time when I noticed a smell of burning plastic. Eventually I started feeling in the dark until I burned my finger on the melted plastic housing of the connectors... only then it hit me what I did. The plastic was completely melted and the connector contacts were all black and burned.

I think I have learned my lesson that night. I am still thinking how things could have been if the guiding worked straight away and I went to bed and left the DSLR imaging overnight (in my backyard), how the whole thing could have started a fire.