OK, I did feel badly about not being able to help you. I dug up an old Miranda Sensorex and managed to correct the curtain tension. Look at my photo. See the TWO screw-sets (each set has two screws, a larger and a smaller) are along the vertical line that is implied by my red arrow, leading from camera rear to camera front. You will see a screw-set near the rear of the camera (right near the red arrow) and the other screw set (identical) closer to the front of the camera. There are two screws in EACH SET with this camera:
the larger screw governs the tension and the smaller screw ALLOWS that larger screw to be turned.
The set you are concerned with is the one closest to the REAR of the camera, as this one governs the tension of the FIRST curtain. Your middle photo (which you sent me in a PM) does show these two screw-sets, albeit a little hidden. They are in the SAME place as mine are.
View attachment 181627
This is important: on each set of screws, the larger one governs the curtain tension and the smaller screw allows the larger screw to be loose of tightened. Turning this larger screw counter-clockwise increases the curtain tension for the curtain you wish to work with. Now, if you simply loosen the smaller screw the larger screw might quickly unravel, so you want to hold that larger screw
as you loosen the smaller screw so that you will be able to turn the larger screw only as much as you want. I would suggest then turning that larger screw about half a rotation to increase the first curtain's tension only a bit. Then tighten that smaller screw (to prevent the larger screw from turning) and check to see if there is an improvement from capping. If so, but not yet a full improvement, turn the larger screw another half rotation and check again. Remember, each time that that larger screw is turned (counter clockwise to increase tension) you must first loosen that smaller screw (while holding that larger screw with another screwdriver!), then turn that larger screw, then re-tighten that smaller screw before you check.
This particular camera is a bit harder to adjust than others, but, with patience, you will be OK. If all fails and the larger screw is not held while you loosen the smaller screw, you can turn the larger screw many times (counter clockwise to increase tension) to restate its original tension, but since you do not have the experience to judge just how much tension is normal, it might be difficult to do this. See next:
That said, I would suggest, before you do anything, that you cock the shutter half way to get the curtain ends visually half way into the film aperture in the back of the camera. Then carefully, gently without bending anything, use your finger to move each curtain "individually", to judge how tense each curtain is in the back of the camera. You might aid yourself by taping the mirror up and using BOTH the front and rear of the camera to gently move each curtain, so that you will have an idea of how much tension each curtain has. Usually, each curtain has the same tension as the other. Your problem is that the FIRST curtain (the one that opens the exposure when fired) is lagging and needs to be a bit more tense.
Price: $5,000 for this advice.
Seriously, it is difficult to type all this out. Call me: 215.569.4949 if you wish to talk quickly about this. If you call and I am out, I will call back, but then will hang up and YOU will call me right back because it is only fair that you pay the toll charges for the duration of the conversation. - David Lyga