Mario RB67 Polaroid Back – Zane Edition
Now that’s a mouthful of a name. Anyway, here’s the DIY guide for this full-featured Polaroid 600 & I-Type back for RB67, Big T (Big Roid), and 4×5 cameras via adapter. Files currently only available for Patreon supporters, but files for the original version can be found on Printables later this month. Happy Holidays!
Materials List, Links, Costs, Pricing
THIS SPREADSHEET has all you need to plan your builds. Suggested pricing. Descriptions. materials list and their cost estimates. Links to my last known purchases. Also includes information for the Big T family of cameras as it is now related to this project.
Pre-Requisite Viewing Material
Since many have shared with me that this will be their first major build, I will provide extra context as well as describe things as beginner friendly as possible. Sorry, 3DP camera pros!
Video #1 below is the most important as it goes over some of the major improvements found in the MRBPz. And this is where you will find the new wiring method and instructions. One update here is that for the STEMMA cable (for the LCD) I now use the 100mm version and cut it in half, so then you have 2 cables for the price of 1.
Video #2 & 3 below show other ways in which the MRBPz can be used (and MRBGo, coming soon).
Video #4 below is how the original MRBP is assembled. Watch only for any build tips and additional context.
Video #5 below is the old way of removing the polaroid processor from the OneStep 2 and OneStep+ cameras. This is only for the original method, but worth watching for any additional context.
Now that you’ve had a few hours of my voice, here’s some more!
Printed Parts Walkthrough & DIY Assembly Guide
Ok one more video. In this one, I go over the print file. The DIY guide that follows down below will go pretty much in the same order.
DIY Assembly Guide
Now that you’ve heard me walk you through all of the parts, you will know what I’m talking about here. I will not re-iterate everything from the video. Mostly additional notes, or any special warnings. Let’s start with the first parts you will print.
- Back Half + Mount Half. Once you choose, the most critical thing to keep track of here is how the felt tape is installed, as well as the mylar strip. It’s important that you firmly press down the felt tape so it has no chance of lifting easily. For any CA glue applications, be sure to use some sort of fine tip nozzle. Test fit both halves before gluing it together.
- DXF and Lightburn laser cutter files for both the foam seal and the felt strips is included on Patreon. Remember the difference between the 1.5mm and 2mm foam seals. I know the sheet is pricey but it is worth trying out the 1.5 first.
- Lid and lock. Straight forward, just remember to source most of the screws from the OneStep2 (OS2) or OneStep+ (OS+) donor camera.
- Front cover. This is just the nameplate, opposite the film bay door. Choose the one with the cold shoe to add a VF for your zone focus build.
- Print box standard vs XL. Choose between one pack capacity or two. Print the latches in TPU.
- Bend the dark slide. Use the tool to bend the end of the darkslide for a handle lip. Push the center part out to add a finger groove. Optional glue-on handle.
The video describes the optional items and mods well, so no need to add anything else other than this above on the printed parts. At this point you should have an assembled body, .
- Polaroid OS2/OS+ Teardown. See Video #1, it goes through what to take apart. Just be sure to protect the ribbon cable from ripping. There is a stiff part of the ribbon cable that you can and should bend into a curl. I bend it in 2 places as seen in the image below, one shortly after the elbow, and then another bend shortly before the end of the stiffened part of the ribbon. This stiffer part of the material will not snap, but the ribbon may shear off on the un-stiffened edges if you don’t add a bit of curl to the stiffer section. Always handle the ribbon with care! See if you can find ways to keep it protected like reinforcing it with tape or plastic.
- Be sure to test the donor camera beforehand! I’ve found that 3 out of every 10 cameras tend to have an incomplete eject cycle, so you usually have to pull on the film frame because the very end gets stuck in the rollers. I don’t yet know how to fix it.
- Firmware flashing. This can be done at any time, but at least do it before installing the ribbon cable. There is a tiny black button on the ribbon cable side of the Feather, it clicks when pressed down. Hold it down and connect the USB-C cable to your computer. Once connected, let go of the button and the Feather should show up as a drive. Copy the firmware file to that drive, right on the root directory. The drive will disconnect once it’s done flashing (a second or two).
- Firmware File is on the Patreon file post.
- Electronics wiring. The image above is probably the best example of how to wire the whole thing and install it into the electronic compartment. The only thing missing here are the 4 M2x12 screws to tie it down to the plastic.
- WARNING: Before you connect the battery make sure the wiring matches above! Red on the switch side, black on the USB-C side.
Usage/Instructions
Charge your MRBPz until it’s at about the 4.2v range. The lowest you can go is usually about 3.7 or 3.6 before it starts to struggle to eject.
E = Empty, there is no cartridge loaded. If it is loaded and there is still showing E, then first attempt to disconnect and reconnect the battery. If that doesn’t work, then unscrew the electronics assembly, and carefully disconnect and reconnect the ribbon cable. Check the cable for any damage.
D = Darkslide is in the pack. The Polaroid factory darkslide card does not eject automatically. Press the eject button for just over 1 full second to start the eject process.
1-8 = Frame number. May they be bangers.
0 = The back is loaded but out of film. Time for a new cartridge!
Be sure to turn the MRBPz on when swapping cartridges. Sometimes when off the counter does not reset with a new pack.
That’s it! Thank you for your support, and I really hope you enjoy this project!