This is my take on the external power supply for old school Polaroid cameras. My best effort to make the SX-70 a pocketable I-Type camera.
It may not be the ideal solution for you, and for that I direct you to Helicord Camera’s wonderful and attractively priced solution (I will get one myself soon).
If you like the look of this solution better, proceed to DIY instructions! I do not plan on selling this as a complete kit because the metal contacts must be custom sized (read on for more on this). If interested in the plastic parts for SX-70, IMpulse AF/SE, and CB-70, purchase here. You can also download the files here.
First thing’s first, WTF is this?
This is a holder for the batteries that come inside of Polaroid 600, SX-70, and Spectra film cartridges. They are all virtually the same, with the Spectra having a slightly lower capacity and cutouts in the cardboard backing that don’t impact anything. The name of the battery is Impossible Impulse Battery, Model I-11. It is 6V, 750mAh capacity. By my estimation, the battery is good for 8-12 film cartridges, or 64-96 frames. On cameras with auto focus and flash this might be significantly reduced, but several persons have reported to be on their 3rd or 4th cycle by now.
This mod is non destructive in the sense that all you will do is either remove the skin/covering, or make holes in it to access the power leads.
Parts & Tool list:
- Printed Battery Holder [Download Files Here]
- Battery from a spent Polaroid film cartridge
- Metal spring plate from a spent Polaroid cartridge
- Razor blade, to remove skin
- Metal shears/cutters to cut up the spring plate
- CA glue or Super glue
- Hot glue (optional for a stronger hold of the leads)
- Double stick tape
Instructions
- Print the battery holder. You will need the base part to help you with locating the holes on the bottom of the SX-70 camera or CB-70 back.
2. If you removed the skin from the camera or back, this is what you will see. The 2 holes directly above the tripod socket contain soldered leads that you can press a piece of metal against to power the camera. We are going to leverage that. If you made holes in existing skin, this is what is underneath. I highly advise you just get a new skin or use the double-stick tape to apply the peeled off skin to the battery holder.
Accommodate the battery holder base until it sits with the holes aligned. If this looks good, then add double stick tape to the back and attach the battery holder base to the camera/back.
3. Time to make the metal contacts. For this, you will need the metal spring plate that comes inside the Polaroid film packs. Be very careful, there are areas of these metal ninja stars that can cut you deep.
Before you bend any metal, now with the battery base attached, measure the depth in each hole until you hit the metal contacts. Add 0.25-0.5mm. This is how long you will need to make the “small pins” described below.
Follow the examples below to shape your metal contacts like mine. I used the vertical sides of the metal spring plate. The “peaks” of the bend should be at about the general area of the red line below.
The small pins seen in the following images are about 3mm wide, and should not be any wider than that, smaller is preferred like 2.5-2.75mm. If you leave some length to it like I did, you can adjust later if they were too short or to long by unbending the small pin part, and re-bending it so it makes contact.
4. Now place the metal contacts in place inside the battery holder base. Check to see if the pins fall into the hole properly. Press down on the bends slightly to test that it helps push the pins down.
Before you glue the contacts down, hold that area with your finger and see if the pin is pushing the plate up about 0.25-0.5mm. This is so you know you are no too short.
5. Use a hot glue gun for an even stronger bond.
6. You are almost done! But first, to test. Tape the lid down very tightly and slide in the old Polaroid battery to see if it works and doesn’t fit too tightly. You will need some sort of film cartridge inside of the film bay so the camera shutter can be tested/activated. If it works, then remove any tape and glue the lid shut.
There you have it, friends. May you enjoy all the savings I-Type has to offer!