Sometimes, when adding a radio preset channel, the Ford Blaupunkt MP3 stereo CD/mp3 player will lock up, then start turning itself on and off. It's possible to fix it with a factory reset, but it's tricky. Here's how.
Time Required: 5-30 minutes
With the malfunctioning stereo turning on and off, you won't be able to navigate the menu to reset it. If the conditions are right, however, the stereo will still play a normal audio CD, which gives you the ability to navigate the menu. In my testing, MP3 CDs don't tend to work.
Insert an audio CD if one is not inserted already. While turning on and off, it may take a few cycles to completely load the CD.
Disconnect power from the head unit. The easiest way to do this is to remove the fuse. On 2000-2004 Focuses, this should be fuse #31 under the dashboard on the far left side.
Wait exactly 5 seconds, then plug the fuse back in. Timing is everything, but if you're near 5 seconds, it should come back on and start trying to play the CD. If it goes back to rebooting over and over again, you should try again, or you may have inserted an MP3 CD.
To eject the CD, you need to rapidly press the eject button until the edge of the CD comes out of the slot. You'll have to grab it firmly and yank it out of the head unit. You may try ejecting and re-inserting the CD, or try other CDs if you have trouble making it play a CD.
Once the audio CD is playing, hit the "menu" button and use the right knob to scroll down to "Factory Reset". Press the knob, select "Yes" and press it again. The display should blip and the CD should stop and start back up.
Hit the AM/FM button, and your presets should be cleared. Be careful adding your presets back, since adding presets seems to be the thing that occasionally triggers the problem.
Lab testing showed that on average, about one out of every 20 times I added a preset, this problem occurred. This also gave me lots of practice in getting the instructions right!
I've noticed that if you have a normal audio CD in the player when the head unit goes on the fritz (again, MP3 doesn't work), it will simply lock up for a few seconds, and immediately start playing the CD, allowing you to reset it before it goes into its power cycle behavior.
Silfox on the Focaljet forums originally posted some instructions after fixing this on his own stereo. Without those, I wouldn't have had a good starting point for experimentation.