stu_jenkins
Member
You only have to undo half a dozen solder joints to get the focusing screen out of an AE-1. Here's how.
To see the full-size versions of these photos, check out my Flickr album here.
TIP: If you need to replace the mirror foam, clean off the remains of the old foam before you start this job.
I'm assuming you can get as far as taking the top cover off. There are plenty of descriptions of how to do that on the web so I won't repeat it here.
You'll need to get the tungsten wire out of the way. Just take the plastic ring off the winder shaft, unthread the wire from the pulleys and keep it safe over on the left-hand side of the camera.
Remember before you took the top cover off you had to set the ASA to 3200 and the shutter speed to B, to minimise the tension on the tungsten wire? Well, having the shutter speed on B is now a problem because it's applying pressure to close the B switch, and that needs to be removed. Turn the shutter speed selector off the B setting to relieve the pressure on the switch (circled in green).
Now you can remove the plate that holds down the main meter / shutter release switch, and also has the white mark for reading the frame counter. When it goes back together there is a slight adjustment range so you can get the mark to line up with the S on the dial.
Next, remove the frame counter dial. It's necessary to do this with the rear film door removed, so the pin in the light seal track moves outwards and disengages the frame counter drive. Try gently moving the dial round anti-clockwise, and when you release it the dial snaps smartly back round and stops at S. You'll need to make sure it still does that when it goes back together.
Remove the centre screw and lever the frame counter dial gently from underneath, pushing up near the middle. Hang on to it because it's spring loaded.
When it comes off, you can see that the spring is captive underneath it. The spring has a hook that engages with another hook in the chassis top plate. At the bottom is a top-hat washer made of soft translucent plastic. When it goes back together you should be able to get the washer to stay in place on the bottom of the counter dial. It's important to make sure that the middle tubular bit of the washer doesn't get distorted though. If it distorts outwards it'll jam against the spring. If it distorts inwards it'll pinch the centre of the dial. Either of those conditions will make it drag, and prevent the dial from snapping quickly back to S.
Now you can release the main switch / B switch assembly. The section of flexible circuit board it connects to will need to be guided out, first past the hook for the frame counter spring and then past the piece of black plastic that it sits partly underneath. If it's troublesome, you could remove a little bit from the corner of the black plastic using a craft knife, but be careful not to damage the circuit board.
The next step is desoldering. This picture shows the six joints that need to be disconnected, circled in green. You might find it easier if you temporarily bend upwards the steel hook that retains the circuit board across the front of the camera (below the little grey plastic block to the top right of the picture below).
Note that the one nearest the front corner of the prism is quite tricky. It's the extended end of the long thin brass rod that goes across the front to form the self-timer switch. It's horizontal where it comes out of the plastic block, but then it bends upward 90 degrees right at the end. Bear in mind that during desoldering you'll need to 'unhook' the circuit board to release it. TIP: For the other two joints next to the prism, use a tiny screwdriver to push the circuit board up from underneath while heat is applied. Otherwise, there is a risk that the copper pad might break off the circuit board.
You'll also need to remove the viewfinder. Two screws hold it in place.
Now you can lift the circuit board away from the pentaprism. Tie it back with string or tape so it's out of the way.
The prism is held in place by two spring clips that pass over a brass retaining cap. Use needle-nose pliers to remove them one at a time, but use your finger to push down the on the retaining cap while you're doing it. If not, the asymmetric force might make the cap flip upwards. Remove the cap and the plastic protection sheet that sits between the cap and the prism.
At each side of the prism there is a piece of fabric tape. Peel it away with some pliers until it's clear of the camera chassis. If the tape stays in one piece then you'll be able to glue it back down again. If not, you'll have to replace it on reassembly.
Now you can lift up the prism and get your first glimpse of the top of the focusing screen. At the back of the prism there is a groove that retains a plastic section to act as a buffer. It might fall out, but if it does you can use a small spot of glue to put it back.
Below the prism is a metal frame that includes the meter markings. Gently lift it out, along with the plastic spacer underneath it.
Finally, you can push the end of the focusing screen up from underneath. Make sure you only push from the right-hand end, not the end with the meter. That way you'll be able to slide it out without disturbing the meter needle or the LEDs. On top of the focusing screen is a clear plastic magnifying element. They're not fixed together. Note that the two ends of the focusing screen are not exactly the same, so be sure to refit it the same way.
Now give the whole area a good clean before you put the focusing screen back in. Otherwise there might be a loose bit of dust or hair that could launch itself across the top of the focusing screen after you've put it all back together.
REASSEMBLY TIPS:
To see the full-size versions of these photos, check out my Flickr album here.
TIP: If you need to replace the mirror foam, clean off the remains of the old foam before you start this job.
I'm assuming you can get as far as taking the top cover off. There are plenty of descriptions of how to do that on the web so I won't repeat it here.
You'll need to get the tungsten wire out of the way. Just take the plastic ring off the winder shaft, unthread the wire from the pulleys and keep it safe over on the left-hand side of the camera.
Remember before you took the top cover off you had to set the ASA to 3200 and the shutter speed to B, to minimise the tension on the tungsten wire? Well, having the shutter speed on B is now a problem because it's applying pressure to close the B switch, and that needs to be removed. Turn the shutter speed selector off the B setting to relieve the pressure on the switch (circled in green).
Now you can remove the plate that holds down the main meter / shutter release switch, and also has the white mark for reading the frame counter. When it goes back together there is a slight adjustment range so you can get the mark to line up with the S on the dial.
Next, remove the frame counter dial. It's necessary to do this with the rear film door removed, so the pin in the light seal track moves outwards and disengages the frame counter drive. Try gently moving the dial round anti-clockwise, and when you release it the dial snaps smartly back round and stops at S. You'll need to make sure it still does that when it goes back together.
Remove the centre screw and lever the frame counter dial gently from underneath, pushing up near the middle. Hang on to it because it's spring loaded.
When it comes off, you can see that the spring is captive underneath it. The spring has a hook that engages with another hook in the chassis top plate. At the bottom is a top-hat washer made of soft translucent plastic. When it goes back together you should be able to get the washer to stay in place on the bottom of the counter dial. It's important to make sure that the middle tubular bit of the washer doesn't get distorted though. If it distorts outwards it'll jam against the spring. If it distorts inwards it'll pinch the centre of the dial. Either of those conditions will make it drag, and prevent the dial from snapping quickly back to S.
Now you can release the main switch / B switch assembly. The section of flexible circuit board it connects to will need to be guided out, first past the hook for the frame counter spring and then past the piece of black plastic that it sits partly underneath. If it's troublesome, you could remove a little bit from the corner of the black plastic using a craft knife, but be careful not to damage the circuit board.
The next step is desoldering. This picture shows the six joints that need to be disconnected, circled in green. You might find it easier if you temporarily bend upwards the steel hook that retains the circuit board across the front of the camera (below the little grey plastic block to the top right of the picture below).
Note that the one nearest the front corner of the prism is quite tricky. It's the extended end of the long thin brass rod that goes across the front to form the self-timer switch. It's horizontal where it comes out of the plastic block, but then it bends upward 90 degrees right at the end. Bear in mind that during desoldering you'll need to 'unhook' the circuit board to release it. TIP: For the other two joints next to the prism, use a tiny screwdriver to push the circuit board up from underneath while heat is applied. Otherwise, there is a risk that the copper pad might break off the circuit board.
You'll also need to remove the viewfinder. Two screws hold it in place.
Now you can lift the circuit board away from the pentaprism. Tie it back with string or tape so it's out of the way.
The prism is held in place by two spring clips that pass over a brass retaining cap. Use needle-nose pliers to remove them one at a time, but use your finger to push down the on the retaining cap while you're doing it. If not, the asymmetric force might make the cap flip upwards. Remove the cap and the plastic protection sheet that sits between the cap and the prism.
At each side of the prism there is a piece of fabric tape. Peel it away with some pliers until it's clear of the camera chassis. If the tape stays in one piece then you'll be able to glue it back down again. If not, you'll have to replace it on reassembly.
Now you can lift up the prism and get your first glimpse of the top of the focusing screen. At the back of the prism there is a groove that retains a plastic section to act as a buffer. It might fall out, but if it does you can use a small spot of glue to put it back.
Below the prism is a metal frame that includes the meter markings. Gently lift it out, along with the plastic spacer underneath it.
Finally, you can push the end of the focusing screen up from underneath. Make sure you only push from the right-hand end, not the end with the meter. That way you'll be able to slide it out without disturbing the meter needle or the LEDs. On top of the focusing screen is a clear plastic magnifying element. They're not fixed together. Note that the two ends of the focusing screen are not exactly the same, so be sure to refit it the same way.
Now give the whole area a good clean before you put the focusing screen back in. Otherwise there might be a loose bit of dust or hair that could launch itself across the top of the focusing screen after you've put it all back together.
REASSEMBLY TIPS:
- If you have one, use a statically-charged brush to give it a final going over before the focusing screen goes back in. I use my VisibleDust Arctic Butterfly brush to catch any remaining loose stuff.
- You'll need to temporarily refit the screw to hold the main switch in place while you fit the frame counter dial, but without the flat plate that goes on top. That's because the plate would interfere with the dial while it's being refitted. Once the dial is back in, remove the screw and refit it with the plate.
- To refit the frame counter dial, put the top-hat washer on the bottom (it should stay in place) and drop the assembly on to the shaft with about the frame 16 mark facing the front of the camera. Don't push it down all the way. The spring hook should be underneath the frame 18 or 20 mark. Looking from the front, start to turn the dial anti-clockwise and see if you can see the spring hook. Use a thin probe to make sure it engages with the hook on the top of the chassis. Continue turning anti-clockwise, but at some point before the S reaches the position opposite the main switch you'll need to lift the dial ever so slightly. That will allow the dial to pass the rotation stop. Once the S is well past its stop position, you can push it down all the way and refit the centre screw. Now if you turn the dial anti-clockwise and then release, it should spin quickly back to S and stop. If it drags, it's probably a problem with the top-hat washer having distorted.
Steve M.
Veteran
Or, simply buy an AE-1 Program camera w/ a replaceable screen :]
lxmike
M2 fan.
Thanks for sharing, great in depth photos
SimonKlanfurt
Newbie
Thanks for sharing, very helpful!