If your body is afflicted with this fault, you will see nothing but absolute blackness upon looking into your viewfinder (even with the lens cap removed), yet your film transport will continue to advance as usual when cocked and fired. In this condition, the camera will still take photographs, however you will not be able to frame, focus or meter the shot you wish to take. In other words, the camera is of no constructive/creative use to you. If sounds like your camera, this tutorial is here to help you.
Contrary to what some messageboards will advise, this fault is not electronic and is not the result of a died battery or failed circuitry. This is true on more advanced Pentax bodies, but does not apply to the Spotmatic series.
Before attempting this particular repair, check the foam "bumper" that cushions the mirror during exposure. It may have become sticky with age and just needs to be cleaned. In some instances, cleaning the top of the mirror with some rubbing alcohol or brake cleaning fluid, and dabbing a teeny-tiny bit of graphite lubricant across the foam with address this. However, this particular method will only work with mirrors that become seized every so often, particularly when shooting at slower speeds. If sounds like your camera, do this first.
Also, this repair method will not help you if your mirror has become seized, meaning that it is stuck mid-swing and/or will not move if even you try to force it by hand. Thanks to Kiteman for bringing this to my attention.
Step 1: Required Tools
- Jeweler's/electronics Philips screwdriver.
- Jeweler's flathead screwdriver
- Camera cleaning "jet pump", compressed air or your own lungs.
- A light oil in a container that will allow for controlled, fine dispensing. (I used brass instrument valve oil, poured into a sewing machine oil container. However, specialty oils made for camera/gun maintenance are available)
- A tray to keep the tiny screws safe while you make the repair.
Nice to have...
- A well lit workspace.
Step 2: Step One
With the mirror ceased in the "up" (exposing) position, your camera will look similar to this. The only difference being, looking into the camera, the material at the back will be a matte fabric rather than a shiny material, as shown here.
Step 3: Step Two: Remove Base Plate.
In my frustration, I have found that keeping the screws lined up in the sequence of their removal helps with replacing them during reassembly.
Step 4: Step Two: Remove the Circuit Board
Using the Phillips screwdriver, remove the three screws that hold the circuit board in place.
Once you have done this, carefully slide the circuit board out from under the clip shown on the right and gently pull the circuit board out of the black wiring harness. Once you have done this, put the board aside and replace the connect beneath the clip.
Step 5: Step Three: Unceasing the Mirror Return.
While looking at this lever and pin, cock and fire body. You will notice that, while other parts of the body will operate, these two components remain relatively stationary, expect for the fact that the lever appears to be struggling a bit. This is the culprit, right here.
Press the shutter button to ensure that the body is not cocked.
Using the flat head screwdriver, gently push the lever to the right, towards the tripod mount.
You will notice that the spring-loaded pin will descend to the bottom of the channel, towards the gears just to the left, and you will hear the mirror drop.
Continue to step four.
Step 6: Step Four: Blow and Lube.
Cock and fire and the shutter. Odds are the mechanism will become ceased once again, as shown in step three, and the mirror be locked in the "up" position. Repeat step three to free the mechanism.
The issue lays with the large cog just beneath the "L" lever. It has become "sticky", and is not delivering enough tension to the lever for it to complete a full operation or "stroke."
Using compressed air, a hand pump or your own lungs (as I did), direct air at this cog and the area around it, such as the channel to the right of the cog. This will free some of the dust and lithium "gunk" that is impeding the operation of this cog. While uncocked and unceased, stick the flathead screwdriver into one of the slots on the cog and gently move it along just a few millimeters (just a tad). The spring should return it back into position. This will help free the mechanism a bit. Apply air once again.
Cock and fire the body a few times. If all goes well, the mirror should function normally. However, you will find that, especially when testing it at slower shutter speeds (60x and bulb), the mechanism will become ceased after a little while. Even it is does not, you will need some lubrication, so continue to the next step.
Step 7: Step Five: Lubrication.
DO NOT USE WD-40 or any similar lubricant! Not even a non-aerosol WD-40 "pen". The problem with these lubricants is that they contain wax, which is great for a small engine meant for outdoor use, but will eventually "gum up" the workings of your camera body.
Now, in order to work the oil into the mechanism, set the body to the fastest shutter speed (1000) and hold it upside down. Keep the flathead screwdriver within reach.
Shoot about twenty-five frames of imaginary film, freeing the mechanism should it become ceased. Now do the same at the slowest speed (60x), freeing the mechanism if it becomes ceased. If all goes well, you should be able to shoot two "rolls" without the mirror return ceasing up.
Footnote:'' Some suggest applying a small amount of automotive brake cleaning fluid to the cog using a similar method before apply the lube. This is meant to clean the old lithium grease and dust that is seizing the cog mechanism. Theoretically, this makes perfect sense and would aid in the repair. However I didn't do this, so I cannot confirm its efficacy .
Step 8: Step Six: Reassemble the Body.
Rejoice! You're Spotmatic is now ready to take photos once again!
This is hardly a replacement for the standard CLA (Clean-lube-align) provided by most repair shops, however this method will get you back up and running for a lot less.