A(-1) shutter problem

Well, I got a hold of a Canon A-1 … not surprising since I just posted a historical note about it … anyway, this camera came with a shutter problem. It appears that it does not trip. For an electronic camera, that is not a good thing since there could possibly be one or more of sooooo many components that is the issue … why I prefer the older mechanical cameras.

OK, so first thing, battery … check camera with fresh battery. Battery check shows good power. I noticed the light meter is working and displaying exposure information in the viewfinder, OK so power is getting through some of the circuit. I noticed that as soon as I pressed the shutter button to take a shot the LED display goes out … hmmm.

OK, now it is time to hunt around the web … well, it appears that there is something obvious to check out … an electromagnet.

Take off the bottom plate.

DSC00698

There are two electromagnets down there … one large one hiding under a plastic cover, and another smaller one on the other side (just follow the red/black wires). The large one is in charge of releasing the mirror and shutter. When the shutter is charged, the trapezoid magnet is pushed against the two metal posts on the electromagnet, where it gets stuck … when the shutter button is pressed, it will send power through the electromagnet that will repulse the magnet and thus release the mirror/shutter mechanism.

You can manually pull them apart to clean out anything that could be causing stickiness between them … but I think the more typical problem is that the electromagnet is not working.

You can electrically short the circuit to send power through the electromagnet, bypassing any electronic issue that is occurring before this in the circuit.

If you look at the flexible printed circuit board, there are two large solder posts beside a screw.  If you short the upper post with the screw (or the contact on the board under it), it will complete the power circuit and should trip open the magnetic contact … if it does not, then the electromagnet needs replacing. In my case that appeared to be the case.

DSC00699 1With a handy-dandy soldering iron you can detach it from the flexiboard. I pulled it out and took a look at it (the plastic cover it a bit of a pain to work around, you might want to cut it.)

There were a couple of coil wires that broke … though I am not sure if I did that when trying to take it out (the coil wire is very very small gauge) … anyway, I tried to solder them together (note that coil wire is coated) … but I still do not get any continuity when checking with a multimeter. This must mean there is a break somewhere else (or my soldering skill really sucks).

A query on a forum confirmed that the A’s share the same electromagnet. Sooo, I decided to sacrifice the AE-1 that I just worked to confirm that this is the problem … the Canon AE-1 and AE-1P both (and possibly the AT-1) have the same electromagnet that the A-1 has.

After carefully swapping them out (too much heat can cause the posts to get damaged or disconnected from the coil wire) I now have a working A-1, and a non-working AE-1.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.