iMac and HDMI to HDTV connection question

[alekq]

Hello all.

This is more precaution than real problem...

From time to time I connect my iMac to my Sony HDTV using mini DisplayPort to HDMI cable. In general, cable is plugged into my iMac all the time (because of practical reasons) and I plug it into TV's HDMI port only when I plan to use it. The main reason for this option is that there are frequent electricity instabilities. My iMac is protected by UPS, but TV doesn't have any protection.

Somewhere I read that when you connect your computer to external display/TV, both should be switched off. After plugging all cables, first you should turn on your TV and after that your computer. I am interested is that only precaution or procedure that should be followed? I haven't found anything regarding this on Apple support pages.

Usually, I don't switch off my iMac - I just plugin cable into TV, turn on TV (display on iMac goes blue for few seconds) and turn on display mirroring on my Mac. After, I just switch off TV (display on iMac goes blue for few seconds, again) and unplug HDMI cable from TV. Everything works perfectly, but I would like to know can I do any harm by using this way?

Thank you in advance.

Alex