One of the more hardcore repair jobs I've had to do in a while
A few weeks ago one of my clients posted asking for a local repair tech as the SX-70 they purchased from me a year + prior would not reset its mirror anymore. They did not want to have to send it all the way back to me if they could help it.
However, I feared the job would not be a simple one, and that the reason for the failure was a snapped mirror return lever. The mirror return lever is a metal piece that is factory press-fit onto splines and really not designed to be replaced. Fortunately this is an exceptionally rare issue, but if it does occur it will 100% brick the camera.
Such a repair is very complex, and given that it requires a spare lever from a good parts camera, it is quite literally easier to swap the entire chassis over instead of just swapping the part.
So that is what we agreed to do. OP would source a chrome SX-70 Sonar (since they wanted to convert their camera to chrome finish anyway, having grown sick of the black) and I would swap over all the important parts. At the time we organised this, I offered up two spare Sonar/Alpha chassis to use, but since OP stated they would now source a spare camera I used up my personal spare chassis in other projects.
So imagine my surprise when I open the package only to find a single camera... Apparently the chrome spare parts camera sale fell through, and I was left now with a broken black SX-70 Sonar, and no Sonar chassis to swap over.
The only remaining solution? Replace a part that was never intended to be replaced.
Swapping over the lever involved:
- dismantling the camera down to the chassis
- desoldering all of the body flex cables
- removing the entire geartrain
- using a dremel to cut the lever free of the metal splines, taking great care to only cut the lever itself, and not ruin the metal splines
- sourcing a replacement lever from an SX-70 Model 3 chassis
- removing the good lever by prying it free from the old chassis. This is not an easy job, as they are stuck on incredibly tightly, and the act of prying it free will almost always bend/mangle a section of the chassis. Luckily we do not need anything else from the Model 3
- carefully aligning and pressing the new lever in place on the old spline. This requires a surprising amount of force, and must be done without bending the chassis or snapping the lever
- re-installing the geartrain
- re-soldering everything
- re-assembling the rest of the camera
I hope I do not have to do another for a long time.