I also cobbled together a quick test for light leaks in the bellows. I used a LED light puck inside an empty film pack and slid it inside the camera. Then I examined the bellows in a dark room to see if I could see light.
I did see a few dots of light low on the gear side but they were blocked when I installed the gear cover. So I'm going to say for now it looks good.
I removed the SX-70 motor to clean the armature and brushes. Despite what I saw Online, do yourself a favor and desolder the motor first before trying to remove it. I struggled and the flex cable really suffered and began to delaminate.
Now that I can shoot 600 film, I'd like to be able to use i-Type film. It's the same film as 600 but has no battery in the pack.
That means the SX-70 needs another power source. There's a few solutions out there. I prefer something that's not permanent/easily reversible and one I can make myself.
Here's my attempt. It's a replacement bottom shell with 18650 and charge/boost.
I modified an existing shell design to accommodate the battery. Bonus is the neck strap mounting points (something sorely missing from the 1st gen).
Buuuut, it doesn't work. The LX-LCBST charge/boost circuit shuts down as soon as the motor is connected. The boost out is rated at 1A but I'm guessing the motor pulls too much as it starts. Boo.
Second attempt at a i-Type battery mod for the SX-70. I call it "The Barnacle" because it snaps onto the bottom of the camera and uses pogo pins to inject power.
There's also a 1/4" tripod mount snap on as well.
Inside is a "18650 battery shield" board that provides charge/boost to 5V (with an added 10uF cap). It also does 3.3V but not using it.
Even though the camera usually uses 6V, it seems to work OK with 5V.
Power is delivered underneath through two small pogo pins.
This idea came from the "remora" case by nunocruz which is honestly a lot smaller than my solution but I have so many 18650 batteries to use.
Looks like someone else tried to make an all in one SX-70 battery mod bottom shell but ran into the same boost issues I did.
https://www.reddit.com/r/Polaroid/comments/1t1ee8b/sx70_battery_mod_help/
Revised the design a little for The Barnacle battery for the SX-70 to be smaller and rounded at the bottom saving some space. Also some legends for attaching it and cut outs for the LEDs.
The board is cool because it has both micro USB and USB-C inputs for charging plus USB-A outputs to power something else.
Being underneath, it points the camera up instead of down so shots on a table with a timer are framed better.
@paulrickards I mean… it’s probably not still too late to just pop an ND filter over the lens, and that way you can use either pack.
@octothorpe The ND filter isn't needed now that the capacitor has been changed.The missing battery from i-Type film packs that is the road block.
I'll probably iterate some more until I find a circuit that can tolerate powering the motor.
@paulrickards @octothorpe
I wonder if adding a fair-sized capacitor across the power input to the camera would absorb the surge current and prevent shutdown.
Of course, too LARGE a capacitor would impose a turn-on load that could also trigger shutdown.
@n1xnx @octothorpe Possibly! Any guidance on a capacitor value to try? It's a 6V supply (fresh pack measures 6.4V).
@paulrickards @octothorpe
Start out with, say, 10 uF and go up from there to 47, then 100, then 470. Use a working voltage rating of 12V or higher. If none of those help, you probably really do need a higher-rated power converter.
I've played with those Polapulse batteries in the past; (ISTR that for a while they were sold separately), and it's notable that their shape (flat, WIDE electrodes) gives them an inherently low internal resistance, which is important when powering the camera's motor startup surge. I recall reading about that in the literature back in the day.
@n1xnx @octothorpe Thanks for this! I tried adding some caps to the board but it still shuts down as soon as the motor is connected. When I tried the 470uF, it struggled to even start up, and would “brown out” at lower voltages. Switching it off and on it would eventually reach the target voltage. But alas, it still shut down too. These charge/boost circuits appear to be not so great. Bummer too, the size is great and has a trim pot to adjust the voltage. Oh well.
@paulrickards @octothorpe
The next thing to try would be adding a second Li-ion cell to boost the voltage, and using a linear regulator. The power consumption is low enough that the efficiency loss of a linear regulator is insignificant, and 3A linear regulators are not too large. There are ways to adjust the output voltage of the regulator to match the battery you are replacing. You'll want a separate power switch to disconnect the battery from the linear regulator when this unit is not in user.
Jul 29, 2026, 5:24 PM@paulrickards whoa. That is really cool with an interesting result. Idve said 18650 as well. I wonder what the solution is.
@paulrickards in my experience step up can be somewhat temperamental. It may even not be a problem of the motor drawing too much current.
Aug 2, 2026, 6:45 PM@paulrickards No idea if this relates. But I recently saw a video that talked about the SX-70 and I think they mentioned the motor pulls 2 (or 3!) amps when ejecting. (also you probably already know that)
@h5e Thanks for that! These are new numbers for me. I've not found a definitive value for how many amps it draws. I wouldn't be surprised if it peaks at 3A though.
Aug 3, 2026, 6:37 AM@paulrickards ok I’ll try and find the vid later! I imagine pulling that amount of juice through a lower power boost circuit can cause weird effects.
Aug 3, 2026, 11:07 AM@paulrickards Here it is!
@paulrickards Wow! All this from a little resistor swap ;-)
Very cool!
@octothorpe Thanks! I'm all iterate, iterate, iterate 🙂
Aug 4, 2026, 9:29 PM@paulrickards This looks fantastic, Paul.If the height of the case is still changeable, it might be cool to have the lens be perfectly horizontal when at rest, but if the camera model has a screw-in tripod feature, that'd be immaterial.
Very impressive.
@Luke Thanks! No camera tripod mount on this model but I did print a tripod mount snap on for the camera.
Aug 4, 2026, 10:01 PM@paulrickards Oh, that's perfect!
(also: love that this thread exists, well done)
@Luke Thanks! I'm glad you enjoy it. I always hope that my tinkering can help someone else someday.
I'm also likely not done tinkering with it yet 🙃
@paulrickards But this is *a lot* more elegant than the barnacle! Wouldn't it be possible to combine the two attempts: Replacement bottom shell with the battery shield?
@PistonPin It is really nice but unfortunately the battery shield is too big and doesn’t fit inside the case. I need to find a different, smaller, boost circuit that works and fits inside the case.
The only draw back to this approach is it’s not quickly removable like the barnacle.
@paulrickards I see. Hmm… Would designing an additional outer “shell” that fits over the actual bottom/cover be doable?
@paulrickards Impossible's reason for having only 8 photos per pack was always "The new battery is thicker, we can only fit 8" (I tried and managed to easily fit in 10 undeveloped photos in an Impossible pack). But now with the I-Type, there's no more excuse for that, but still only 8 photos. Mildly infuriating.
@paulrickards thanks for documenting everything so well here! I've been shooting on my SX-70 ever since the Impossible Project started making new film. The early experimental film was so fun to shoot with! They had a store in Vienna where they would sell test batches straight from the factory for cheap.
@karpour Sure thing! Documenting for others but also myself so I can remember what I did 🙂 Shooting the test batches must has been fun!
@paulrickards it was! In the beginning, the film was 2-color, giving photos a really unique look. Then, when they developed the BW film, they had a test batch they sold as "orange flash". The photos would come out pretty wild, you would get crystals, and you could also influence development a lot with temperature. That was one of the most fun films to shoot with!
@karpour Wow that sounds like fun! I used to draw on my Polaroids as they were developing 🙂