Polaroid SX-70 Repair tips/usual suspects?

--I posted this in the repair forum as well, but figured you all may have a more nuanced understanding of this camera--

Hi all--

Got my hands on an early SX-70 for a good price this past weekend. Tested with two different packs of 600 film (Im aware of the whole film debacle) and was met with essentially no response: no darkslide ejection, but the mirror did manage to move when pressing the shutter button. It wasnt a full shutter cycle, but Im hoping that means there is still power getting through and some mechanism is just getting caught up on old gunk.

Mostly coming here looking for any tips/advice about usual suspects to look for, as I intend to tear it down and see if I can get it back up and running. Weirdly, at a glance I didnt find much helpful info pertaining to the typical issues of the camera-- all I've come across is some mention of a switch that is associated with the opening of the camera and dirty battery contacts. I tried to take a look at both with no improvement. Any other things to look out for would be much appreciated.

I believe it is a model from 1974 if that affects anything.

Thanks! I've heard plenty of good things about this cam, not willing to give up on it yet

I will try to help you. Disclaimer: I'm not a repair person and I'm not a specialist. This is what I do and you act at our own risk.

Take the cartridge out. You will lose at least one photo. If you want to prevent this, consult the web how to avoid.

Check the voltage of your cartridge. It should be more than 6 volt. If not, your cartridge won't work and you will have to get a fresh one. That may solve your problem.

If the voltage is fine, you can try to reset your camera. This is how to proceed:

On the left side of the SX when you hold the lens towards you there is a black plastic piece that covers a series of gears. To remove it, you just have to lift this piece, starting at the yellow lever where there is the white arrow on a black background. It is just clipped in, no need to force it.

Then you have to turn one of the dented wheels that act as a gear. It's the second but last towards the back, it has to be moved counter-clock-wise. Look at the photos of a French website here https://www.polaroid-passion.com/forum/viewtopic.php?f=5&t=2375 to locate the gearwheel.

On a full cycle, you will hear a mirror up sound, sight of the viewfinder is obscured. A long time after having continued to turn, you will hear a click of the bottom lock of the mirror, one can see through he finder again. End of the cycle. Going through the cycle again doesn't harm the camera, but it may help an old camera to come to life again.

Good luck!