Okay, so I bought this thing a couple months ago on eBay for a decent price. Flash works great, autofocus doesn't (and it drains pack batteries while the camera is sleeping). So, hey, I can still use the manual focus. But I have two SX-70s...what's the point? Except to be able to use 600 film in a native SLR, it's mostly just a bigger, more awkward SX-70. Instead of reselling the thing on eBay for next to nothing as a broken camera, I've decided to pull it apart and see what's what, if I can maybe fix this thing.
I searched the Web and found next to nothing about repairing this camera. There are a few attempts at SX-70 Sonar repair, but nothing about the 680. I have serious doubts I'll be able to make this thing work, as my knowledge of electronics is close to nil, but at least it's fun to take things apart and find out what makes them tick.
First step was taking the covering off the front. I've done this with the SX-70, but the 680 has an extra big sonar thing, and the two parts seem to be connected somehow. I initially just tried prying it apart.
It would almost come off, but it seemed to be stuck pretty fast on the non-flash side. I tried popping off the lens casing, which is pretty simple on the SX-70. Almost as simple here, but still caught under the sonar casing.
After messing about for 10 minutes or so, I popped off the Polaroid logo on the front of the sonar casing. A screw...duh.
The screw was a funny little square deal, but a regular flathead worked fine. Once the screw was out, everything just fell off like butter (because we know butter just falls off of things, right?).
The inside of the SLR 680 SE...
The sonar is just sitting there and can be pulled loose with little effort.You can see the flash and power supply for the flash. The shutter button works by completing the circuit. Funny thing is, as soon as I pulled it apart, the camera focus seemed to work fine. I've read that the SX-70 Sonar can get stuck on infinity. Here is a video of the camera in action. You can almost hear my own circuits clicking as I pause and work out what I'm doing.
It works! But, then it suddenly didn't work. And I have no...idea...why. Another video of me screwing around...because I was using a screw to fire the shutter. Ha. It just keeps going click click. click. click. Then it takes a shot. I can see the gears attempting to turn, but nothing happens. And when I try to manually turn the focus knob, it fights with me and pulls it back to infinite focus again.
So that's as far as I've gotten. Will mess about some more, maybe see if I can access the mechanisms behind the shutter button. Not sure if the issue is with the focus elements, or with the sonar itself. Nothing looks corroded, just dusty. I assume there is some kind of minor short somewhere that causes the pack to drain while the camera isn't being used. A lot of it is just circuit board and wires, so probably not a lot I can do with all of that. Hell, if all else fails, maybe I'll just remove the sonar body and use the camera as a manual 600 SLR. Maybe not. Any ideas, leave comments! This electronic stuff is a bit beyond my skill level. But only one way to learn, and that's by doing!
I had planned on getting something accomplished today, but got sidetracked by camera stuff. Now I can't remember what I needed to get done! Oh well, it probably wasn't fun anyway.
EDIT: Okay, as I mess with this, I guess I'll just add on here. So I figured a couple things out. One, I unhooked a spring behind the focus knob by mistake, which took a surgical procedure with two pins and a hemostat to reconnect. That was loads of fun. It's the little silver spring above the wheel. I also discovered a couple other things. Check out the picture below...
The shutter button is made up of three "pins" that I have labeled. The one labeled "fires shutter" is probably more accurately the final circuit for powering the shutter, as it cannot fire the shutter on its own. The lower left controls the exposure. When you connect it and the power pin, you can see the aperture opening and closing (two metal slides behind the lens). This is the clicking sound you hear in the second video. Now the last pin, upper left, is the sonar. When you connect it with the power, you can actually hear the sonar firing. So I assume that this should also control the focusing mechanism, bringing the lens in and out from the camera. In this exciting video, you can sort of hear the sonar clicking.
Okay, so the sonar is reacting...but it's not communicating with the lens, or the lens isn't responding. Or the sonar isn't reading properly...but even if it's not, it should still at least focus incorrectly and not do nothing at all. Which is what it was doing originally. And it did work all of a sudden when I first took the camera apart, for no apparent reason.
Maybe the problem lies somewhere with the front? In this video, you can see the auto-focus fighting with me to set back into place when I try to move it.
When I depress the manual switch, I can freely move the dial, but if I let go, it has to be forced to move. It only reacts, though, when I reset the focus to infinity. I can hear it click back into place. Now since I don't have a working 680, I have nothing to compare it to, but I assume that it is supposed to automatically take over regardless of lens position when you set it to automatic. But it only takes over when reset at infinity. You can also hear it disengage when you set the camera to manual and turn the focus knob.
Referring back to the photo posted earlier, flipped for proper orientation...
The red coils are the power supply for the aperture. I may be calling all these things by non-technical, i.e., wrong, names, but you get my drift. They are probably capacitors or something, but what do I know. The round thing to the left of the sonar (below the flash battery) is the power supply for the sonar. It's what the auto/manual switch is attached to, and I assume you are just breaking a connection when you set it on manual. The sonar board connects to the power supply via the red and black wires. So I have I think four possible problem areas. One, the sonar itself, though that is basically comprised of a metal plate. Second, something on the circuit board for the sonar. Next, the power supply...though the fact that I can hear the sonar responding and it wants to take control of the focusing means that it probably works. Last, something between the power supply and the lens itself, in the mess of gears. Something may not be connecting or communicating properly.
Them's a lotta words. My guess is it's the circuit board. And maybe specifically the connecting wires from the sonar to the board. Under the solder, there is a brown stuff, like glue gone bad. Though this may be from the heat of soldering on plastic. But there is obviously a connection or you wouldn't hear the clicking. I'm not sure what the sonar actually is...it's deceptively simple. It just looks like a copper plate with a screen over it wired to the circuit board. Which is probably exactly what it is. I'll have to read up on the SX-70 Sonar, see if I can find out more about it.
Anyway, that's all I have for now. I'll probably continue this in another post when (or if) I figure something out, rather that adding to this post infinitely. Until then...
Once more for today, then I'm done. I figured out that the white cylinder is not a power source or battery, it's the motor that controls the gears for the focusing. Another video.
So to summarize, here is the front and what I know is what:
The motor is connected to the lens by a series of gears set behind the electronics. When I disengage the motor by pressing down on that switch, and twist the manual focus, manual works until I let up on that disengage switch. Then to re-engage the auto, I press down on the manual/auto switch, then let go, reconnecting the circuit and auto resets the lens by itself.
So the issue isn't between the motor and the lens. And when it was temporarily working, the flash was angling up and down properly (and the flash works as well). And because I can hear the sonar clicking when I complete that circuit, the problem must be within the line between the sonar and motor. Someone suggested a short, which makes sense. The next step will be following the various circuits to see if I can figure out what connects to what. I'll probably have to take the board off to see the back side. I may just put the thing back together once in case it magically starts working...but I doubt that will happen.
Haha, most people are probably looking at this thinking, okay guy, show us some more pretty pictures. Enough of this rambling "you don't know what you're talking about" electronic stuff!