Don't start arguing about AE1P vs NF1 - I was a camera technicial for 10 years - 5 of those as a Canon factory tech in the days when FD was still manufactured and th eEOS 1 had just been introduced.
Both are good cameras - I shot motorsport for various magazines for 10 years - anything from touring cars to F1 bikes, F1 cars and world superbikes, with a bit of drags thrown in....
I used AE1P's with motordrives for a few years before switching to NF1's, and you can't see a difference in the photos...plus the A series motordrives have a switch on the body of the motor grip - if you have the motordrive set to single shot and something happens you press the button and it goes to high speed continuous drive. On the F1's I had to have the drive set to high speed continuous and press the shutter button carefully so I only shot a single exposure each shot, but had the option of continuous if something happened (like the time a car went around a corner, rolled, became airborne, and then rolled another 14 times.....- but thats another story..)
Back to the AE1P. Remove the 2 or 3 screws that hold the bottom cover on (chrome have 3, black have 2 screws..). On the end where the motor drive contacts are you will see a magnet with a plastic cover on it (there may be some black tape over the end of the magnet - peel that offirst carefully).
You will now see the magnet is held in place by 3 screws and its 2 contacts are soldered to the flex (the flexible PCB that runs to the top of the camera) - unsolder the 2 contacts, then remove the 3 screws (1 silver screw through the flex, plus 2 at the end of the magnet) and you cna lift the magnet out.
Now grab the plastic cover at the end where the hole is and gently pull forwards and the magnet will come off - now you can get to and clean the magnet faces. Use a clean white card (like a business card) dipped in alcohol (meths/shellac/ethanol) - close the magnet on the card and move the card back and forwards. Do this a few times and the magnet faces should now be clean.
Reverse what you di above and hopefully the camera will work correctly again. You don't need to refit the plastic cover - it is there to keep dust from the magnet faces, but if you leave it off you can clean the magnet faces every so ofter if needed.
If you have trouble following all this you can download a service manual off the net for free from the old americal camera repair school (sorry I cant remember what they were called whcih explains how to do it) - just google Canon AE 1 Program service manual...
If all else fails take a photo og the bottom of the camera with the base off and email it to me - I'll draw some instructions on it and email it back yto you..
Cheers