I've bought a magnetic 120mm fan filter to go on the bottom of my brother's HTPC case, which will prevent the PSU sucking in unfiltered dust/cat hair from outside the case and is also easy for him to remove to clean from time to time. I'm a little bit concerned about the magnet possibly damaging the HDD though. The PSU is at the bottom rear of the case and the HDD at the bottom front, so normally the fan filter won't be near enough to the HDD to cause any problems, but I'm wondering whether I need to warn my brother to take care when he removes the filter to clean it, that he doesn't let it go anywhere near the front of the case to avoid damaging the HDD?

Or would it have to be actually touching the HDD to cause any problems and couldn't do any harm at the distance it would be when outside the case in the area where the HDD is located?

Caution is always wise but it would take much stronger magnets to harm the driver from a distance. Touching the drive with one of those magnets would not be a good idea, but otherwise it's safe.

Thanks for the advice and reassuring me that I'm worrying needlessly I hoped that would be the case and that there was no need to worry my brother with stories of terrible things that will happen if he moves the filter one inch too far to the right Computer's worry him enough already

agreed.
further reading

Thanks for the extra info.

OK, here's another (sort-of) related question.

Is there any reason to be cautious about vacuuming the front fan filter (it's not removable)? Obviously I would advise turning the PC off before doing so.

Hold the fans in place if you do so, a vacumn has a crapton of suction/pressure and could damage your fans if they spin too quickly in any direction.

Vacuum cleaners can generate static charges strong enough for that to be potentially risky. What I've done a few times is putting one hand on the end of the vacuum nozzle to act as a buffer(not touching any part of the case with the nozzle itself). But today when cleaning a filter I use a strip of tape to catch the dust from common fixed mesh-filters, try that first.

Thanks, I hadn't even considered that, only that it would be a bad idea to have the vacuum sucking whilst the fan was running and pulling air in the opposite direction! I was thinking more about possible electrostatic charge.

I think it's going to be quite tricky to hold the fan whilst vacuuming the filter, as the drive cage is rather in the way and whilst it's removable, I don't really want my brother having to do that. I originally planned to cut off the (rather ugly) lower part of the fascia, below the power buttons, http://www.aerocool.com.tw/index.php/pr ... v/121-vs4w , screw a piece of black wood to the case with a hole cut out for the air intake and screw a filter (or use a magnetic one, although I'd need to get some stick on magnetic strips) to that but I was 'convinced' by someone that it would look a bit rubbish, although I think he was biased as he knew he'd end up doing most of the work! I bought one of these filter/frames to do that, but I haven't managed to work out how to separate the parts yet! http://www.ebay.co.uk/itm/120mm-PC-Comp ... 43a9b52499

Yeah, that's what I was concerned about. As you can see, with the Aerocool VS-4 it's not really possible to use the tape method, so I think I might have to go back to my original plan of modding the fascia to fit a removable filter. http://www.aerocool.com.tw/images/case/ ... vs_4_6.png

I've decided to use a removable magnetic fan filter on the front intake as well as on the bottom for the PSU intake, so they can be removed for cleaning and avoiding any chance of damaging the fan or creating static with a vacuum.

I had to cut away the lower half of the fascia and fit a piece of wood with a hole cut for the fan intake, then buy an adhesive magnetic frame for the filter to attach to but I think it was worth it.