How to fix the EOS 5/A2 Command Dial

How to fix the EOS 5/A2 Command Dial.
Also works for the EOS 100/Elan.

by Jim Strutz

Contents

  • Introduction
  • The Fix
  • What You Will Need
  • Getting to the Heart of the Matter
  • The Fix is In
  • Re-assembly
  • Revision History
  • Comments
  • Introduction

    The EOS 5/A2/A2e has a commonly reoccurring problem. The Command Dial (the one on the top left of the camera) sometimes fails. There are actually two related problems with somewhat different symptoms that this document will address. The same, or very similar problems occur with the EOS 100/Elan cameras as well. Both cameras can be fixed in much the same way. In fact, the repair procedure pictures that accompany this document are of an Elan.

    The first and probably most common problem is the Command Dial will spin freely but actually do nothing. It’s like the dial itself is disconnected from the camera, without detenting and no control of the camera. This is usually caused by the plastic rivets that hold the external parts of the dial together to the actual mechanism below, have broken and need to be replaced.

    The second common problem is the Command Dial will spin freely, without detenting, but still controls the camera functions correctly. This is caused by the detenting spring and/or the detenting ball being displaced from their proper position.

    Either of these problems can quickly lead to the other and are often found together. You should note that Canon’s standard fix for this problem is to replace the whole top of the camera. For a long time this simply meant that your camera was subject to the same thing happening again. I understand that Canon has redesigned the replacement part and hopefully this will cure the problem for good. Also Horizon Electronics, a Canon dealer and repair center in California has come up with a fix that replaces the weak plastic rivets with metal screws. As far as I know, this is a permanent fix as well. The following instructions are probably similar in concept to Horizon’s fix.

    What most photographers report happening first is that the Command Dial becomes stiff & the detenting is too hard or feels like it’s grinding. Personally, I would fix it as soon as I noticed this, since the repair would be easier and probably would only require the replacement or shortening of the spring.

    The repair of these problems are not usually difficult, but you do need some technical ability and a sense of adventure since you are about to destroy what use to be a perfectly good camera. Just kidding. Actually, if you get the camera apart and give up trying to fix it, you probably haven’t done anything that will cost you more to repair than before you started.

    The Fix

    What You Will Need

    You will need a good small (size 0) Philips screwdriver, and small forceps or very thin needle nose pliers. If your problem is the first one above, you will also need a very small drill bit to remove the broken rivets and drill holes for the two very small screws that you will need to replace the rivets with. These can be found at jeweler’s supply houses or perhaps watchmakers shops. You may also need to replace the small but stiff detent spring and perhaps the detent ball if it has disappeared.

    The spring and detent ball are about 2mm in diameter. The stiff push type detent spring on the Elan is about 6-8mm long. It’s been a while since I had an EOS 5/A2 apart but I do remember that the spring was longer on it. Perhaps 10-12mm. All these are very rough estimates based on visual estimates and a rather poor memory. Perhaps someone would be willing to provide better measurements when they do the repair. The screws that I used had a diameter of the threaded part of just a bit over 1mm. These are small screws and might be hard to find. I retrieved them from several old lenses.

    I have found a reasonably good supply of small springs and screws at my local Lowe’s Hardware store. But there are also good small part/tool suppliers that advertise on the web. Check out http://www.mcmaster.com/ or http://www.microfasteners.com/ or http://www.harborfreight.com/

    Getting to the Heart of the Matter

    First you need to remove the top of the camera. There is a screw inside the flash on the EOS 5/A2 models, so pop the flash up before you remove the battery & look in the front of the flash housing. The EOS 100/Elan has this screw in front and below the flash instead. To remove the top cover you also need to remove the front cover of the EOS 5/A2 and the door latch assembly, just to get at all the screws. With the Elan you can just loosen the front cover since it doesn’t hide any screws. Don’t forget the screw over by the right strap lug, and the ones in back beside the viewfinder.


    The screws in front are under the front cover plate of the EOS 5/A2 but are exposed on the EOS 100/Elan. (That’s why you don’t have to remove the front cover plate of the Elan.) To remove the front cover plate of the EOS 5/A2 you will need to remove several screws on the bottom of the camera, and perhaps one by the battery compartment. (Sorry I can’t remember this part clearly, it’s been too long since I had an EOS 5/A2 to work with.) There is also a screw inside the battery housing that holds the top cover as well. The battery housing is completely different with these two cameras and it’s much easier to get at the screw of the EOS 5/A2. On the Elan, the screw you want in the battery compartment is the center one. It also holds a small cover plate that should be removed with the screw. When you think you’ve gotten all the screws out, start wiggling the top cover off. Don’t pry it or use too much force. If it seems stuck in some area (it probably will) it’s probably a screw that you missed. Keep looking.

    Once the top cover is loosed, pull it up and pull the small ribbon cable out of it’s rectangular white connector on top of the mirror housing. You can get it loose by lifting the top collar of the white connector up first, then the ribbon cable will come loose. The rest of the wires can be left alone for what you need to do. You’ll want to have more space & will be tempted to remove more wires. You can if you want, but you really don’t need to. Just pull the top cover up and lay it over the front of the camera.

    Now you can see the Command Dial. The small metal detent ball is usually just laying around stuck in the grease somewhere close. The spring that pushes it will still be there as well but it may be twisted beyond use. Be careful that you don’t loose this spring even if it is destroyed, as you will need it to help determine a proper size to replace it with. There is another spring in this mechanism that pushes up the lock release button (the button in the center of the Command Dial). This spring is larger in diameter but uses smaller wire and is much less stiff. To get at it all you will need to remove the screw in the center of the Command Dial that holds the lock release button to the metal tab.

    The Fix is In

    The way it’s supposed to work is, the spring & ball are in the center of the Command Dial just under (since you are holding this upside down) the metal tab piece that is connected to the lock release button (the button in the center of the Command Dial). The spring is supposed to push the ball into the slots in the metal cage, providing the detenting action while you turn the dial to different exposure modes.

    The picture shows an EOS 100/Elan Command Dial. The EOS 5/A2 dial looks a little different, but functionally is it nearly the same. Also the picture shows the two screws that have replaced the black plastic rivet heads.

    If the problem with your camera is just the detenting action is missing, you would simply need to put the spring & ball back in their positions between the plastic side rails that hold them in (these are just molded parts of the Dial) & just under (since you are holding this upside down) the metal tab piece that is connected to the lock release button. But if your camera’s problem is the plastic rivets that hold the metal piece to the Command Dial are broken, you will need to replace them with very tiny screws. You might be able to find some suitable screws in old photo equipment, or watch/clock works. Then drill very small holes for the screws with a tiny drill bit. Then place all the parts into position and screwed it all back together. Only a bit easier said than done.

    This picture shows the holes that were drilled for the screws. The holes are in exactly the same position that the rivets were. The rivets, by the way, are in reality just small stick-like extensions of the Command Dial plastic. To drill the holes first cut off the rivets flush with the dial base. Then use a pointed tool (a nail will work) to force a small dimple in the dial where the rivets were. This will assist you in lining up and holding the dril bit in the proper place.

    These holes and the screws that go in them are very close to the center of the Command Dial. and they may cause the center hole of the Dial to become deformed, tightening the Command Dial’s lock release button considerably. A couple of times I have resorted to whittling on various parts to make it work again.

    If the detent spring is still intact you can re-use it, but cut 2 coils off of one end to loosen the tension. That excess tension is one of the main problems with the dial. The little ball is just being pressed too hard and too deep into the slots of the cage. Loosening the tension of the spring will relieve the pressure on the detent ball. If you can’t use the same spring find another that has a little less tension. Small push type springs can be hard to find. You can substitute the more common pull-type spring by stretching it out so that it becomes a push-type spring. Also a ball with a LITTLE larger diameter can be used to lessen how far the ball goes into the cage. In that case you would want to keep the spring tension high.

    You may notice in the pictures of the Command Dial that I have tapered or rounded off the lower edge of the plastic latch, where the metal tab piece of the lock release button rests in home position. This allows me to turn the Command Dial from the locked position to the Creative Mode positions without pushing the lock release button. If you round off the other side you would have the same function for the PIC Mode side of the dial. Since I seldom use PIC Modes, I left that side unaltered. This provides a dial stop for the locked position.

    Re-assembly

    After you have the Command Dial back together, reattach the flash’s ribbon cable and tighten it’s collar down into position. Then you just line the Command Dial’s actuating slot (on the opposite side of the dial from the detent ball), with the clear plastic pin sticking up from the rotary switch inside the camera, and place the top back on. You may have to work at keeping the flash compartment’s wires routed to places that don’t hinder the top from easily and fully coming to rest in it’s proper place. Then put all the screws back into their right holes. Good as new. Better than new actually, as it shouldn’t happen again.

    Jim Strutz 10/04/2002 02:27:07

    © 2002 August 25 Jim Strutz for EDP.