When you sync an iOS device to iTunes, it is backed up; by default, this backup goes to your Mac, but you can also set it to go to iCloud. When you save backups on your Mac, there's plenty of data and settings saved, so you can restore the device, or even set up a new device, using a backup.

Dave Hamilton, writing at The Mac Observer, recently pointed out that you can also archive backups. To do this, go to iTunes' Preferences, then click on Devices. Right-click or Control-click on one of your devices, then choose Archive. The name of the backup in the Device Backups list will change, to contain the name of the device and the date it was last backed up. The next time you sync your device, iTunes will create a new backup, and retain the old one.

Interestingly, when I checked my backups, I found a number of older ones, with dates, that weren't there before. I suspect this feature is new to iTunes 11.0.3, the latest update to iTunes, because I'd not seen these older backups before.

The Power Management Controller (PMC) failed for the center (hard disk) fan in my iMac Core 2 Duo 3.06 27-Inch (Late 2009). The two outer fans work perfectly, but no center fan gets no power at all.

It took me three tries, but I finally got it right. It's an ugly fix, but it works great.

1. First i got Marcel Bresnik's free Temperature Monitor to read the disk's temperature. It shows the hard disk temperature in the dock. when it started to show close to 130 F, I would shut down the Mac. This was unacceptable.

2. I got a small, square USB fan and attached it over the rear center hole with velcro. This made the heat buildup at the hard disk worse. I figured the new fan was blowing air out of the original fan's intake, so air was moving in the wrong direction. And I couldn't tilt the screen down.

3. So I watched some how-to videos before cracking the case. I had to pull off the motherboard to access the center fan and place a double layer of clear tape over the fan's intake. Then I re-attached the USB fan on the back, and this seemed to cool the disk much better. However, I still could not tilt the screen down. If you are comfortable with the screen not tilting downward properly, you could stop here, but I got better cooling by continuing...

4. I found a short piece of hose from a vacuum cleaner, which even had a small HEPA filter. Then I made a small wooden box for the fan, complete with the air filter.

Next, I used a hole saw and cut a 2-1/8 inch circle out of the stand, directly behind the iMac's center air hole. I installed my custom-filtered fan on the stand with more velcro, and the hose running thru the stand hole directly into the center hole of the iMac. The original fan's air intake is still taped over.

Benefits:
a. My hard disk's temperature has not exceeded 120 degrees in over three years. I keep Temperature Monitor in my Dock to make sure.
b. The two (working) original fans operate normally, without additional software. I think this is important, as I doubt they were intended to run at full speed forever, and running them at full speed pulls dirt into the machine.
c. The new fan makes a very, very small amount of noise, and it's filtered air.
d. The three-inch section of vacuum hose extending thru the stand hole has enough flex that I can tilt the screen easily, while maintaining proper air flow.
e. I already had a hole saw, so for me the only cost went to a cheap USB fan.

Notes: Opening the iMac case is not simple. The hard part is getting just the right parts. You need a suitable USB fan, a fan housing (filter optional), wide cellophane tape, velcro, some kind of 2-inch hose that is flexible, a drill that isn't too fast, and a hole saw available for $10 at any hardware store.

Cutting the hole is scary to think about, but it's a lot easier than it sounds. It does not harm the integrity of the stand (there is already a larger hole in it). The aluminum is soft enough to cut cleanly and easily. Put a piece of paper underneath to catch the filings, and don't allow the aluminum particles to enter the iMac. Mark the center and use the saw's center bit to start the cut and maintain the center position. Do not try to go too fast, or press hard. It cuts like butter!

Do not use a high-speed drill; it will get hot, and you don't want that. Use a medium- low-speed drill and take your time. You might even pause for a few minutes halfway through the cut to avoid heat build up. It will stay cool enough that the silver paint will be completely unaffected. A nail file will clean up any sharp edges.

In the end the only problem is that the fan uses one USB port, and I guess it looks a little strange when you peer around the back, but i don't care about that.

[kirkmc adds: Well, I have to admit, I'd never have done something like that, and I find the solution quite creative. It's certainly a lot cheaper than replacing whatever part of the iMac would need to be changed.]

If you're unable to login to FaceTime and iMessage because the login process repeatedly loops, check the time settings. If the time is not set to automatically adjust (Settings > General > Date & Time > Set Automatically > On), you might find that the login sequence for both FaceTime and iMessage loops. Once you set the time to adjust automatically, all is back to normal.

[kirkmc adds: I've never had any problems, since I've always had that setting set to On. But I've found that a number of odd settings can affect logging into Apple services, so it's worth pointing out.]

If you have a Mac with an SSD, and limited storage space, and use Dropbox, you may want to think about how much space your Dropbox folder takes up on your disk. Jeff Carlson, writing at TidBITS, had this problem, wanting to use Dropbox's Camera Upload feature on his MacBook Pro, but not wanting to have the space taken up on his SSD.

The solution he explains is relatively simple: it involves creating a symlink for the folder in question after moving it to another disk or volume. After moving the folder, open Terminal, then type:

cd ~/Dropbox

Type ln -s, then drag the folder from its new location into the Terminal window, which will add its path; press Return.

This symlink lets Dropbox use the Camera Uploads folder, as if it were in the main Dropbox folder, yet the files are stored on the external disk.

You can do this with other Dropbox folders as well. For me, I use Dropbox's Selective Sync (Preferences > Advanced) to choose which folders get copied to my MacBook Pro, and have everything on my Mac mini, which has more storage.

I use dictation a lot on my iPhone. I have big thumbs, and typing on the iPhone's keyboard ledas to myna rerrors. So occasionally, when I see the dictation button is dimmed, I get quite frustrated.

iMore recently posted an article about how to fix this issue.

Apparently, this occurs when memory on the iOS device gets too low; the solution is then to force-quit as many apps as possible. You do this by double-pressing the home button to show the application switcher, then tapping and holding an icon until they all wiggle. Tap on the "do not enter" buttons at the top-left of the icons to quit them. Press the home button again to close the application switcher.

Since I saw the above article last week, I haven't had the dimmed dictation button, so I haven't been able to test this. I'd been restarting my iPhone when this problem arose. If you've seen this problem, please post in the comments to say whether this solution works for you.

While this isn't strictly a hint anymore, it was back in 2003 and 2009. The Safari Develop menu - formerly called the Debug menu - offers a number of nifty features for web developers. In addition, it's been greatly enhanced under Mountain Lion.

So, to activate this, you no longer need to run a Terminal command; just go to Safari > Preferences > Advanced and check Show Develop menu in menu bar.

Have you ever found that FaceTime won't let you log in even though your Apple ID and password are correct? I had that problem with a client's Mac, and nothing I tried did work. After eliminating all the obvious things, such as testing with other IDs, user accounts and even other systems, I discovered the reason.

As it turns out, FaceTime is dependent on a correct logic board serial number. This is also true for other services like iCloud. This particular Mac had its logic board replaced a long time ago, and the technician forgot to set the serial number on the new board. So instead of the regular serial number it said SystemSerialNumb in System Profiler. After setting the serial number to the correct one, which can be found on every Mac's housing, FaceTime would log in and work flawlessly.

In case you are wondering: every Apple Authorized Service Partner has access to a bootable image which contains a tool to write the serial number to the logic board.

[kirkmc adds: Interesting point. I recall having had a logic board change some years ago, and the serial number was not set (as I discovered when the Mac needed to go into service again). This was around the time that FaceTime was launched, and I could never get it to work on that Mac. It's too far in the past to be sure, but this might have been the cause.]

No hints today, as some of us celebrate Memorial Day, and others the "late spring bank holiday."

Siri's ability to access Wolfram Alpha lets you access a huge amount of interesting data by talking to an iOS device. One useful thing thing Siri can do for you is ask Wolfram Alpha to generate a very secure, random password.

To do this, invoke Siri, then say "Wolfram password," or "Wolfram Alpha password." This retrieves an 8-character random password, along with a list of a half-dozen others. You can also have Siri get longer passwords, if eight characters doesn't ring your bell. Say, "Wolfram 14-character password," for example.

The downside to this is that you can't copy this password, and once you've switched away from the Siri results, you can't get them back again. So you need to either type this password on a computer or other iOS device, or write it down. Either way, make sure you delete it, or store it in some sort of encrypted file.

Agile Tortoise's Drafts is a nifty tool for writing texts and doing things with them on an iOS device. I use it mostly for the more comfortable writing environment, and send texts as emails or tweets, but there's an entire sub-culture that's been hacking Drafts to do many things. (Check out the Drafts actions directory.)

David Sparks posted an interesting use of Drafts (credited to Milosz Bolechowski; I couldn't find the original on his site), together with noodlesoft's Hazel - a tool that automates tasks on your Mac - to put a Mac to sleep. In essence, Hazel looks for a file named "MB sleep" in a the Drafts folder in his Dropbox folder; when it finds that file, it puts the Mac to sleep with an AppleScript.

I think you might be able to do this with folder actions as well, but I'm not very good with AppleScript. So if you can, feel free to post a script in the comments.