I bought this Polaroid 240 Land camera from a vintage shop in Stockport for £5 a while ago, knowing that it needed a bit of work to get it functioning again. The original 4.5 volt battery had corroded quite badly in the battery case and this size of battery is no longer readily available.
I bought a new 3 x AAA battery case, with external switch for £2.25 in eBay, cleaned the corrosion up, then took out the old battery connectors and wired up the terminals to my new battery case. I then used sticky-backed Velcro on the outside of the camera, and on the back of the case to adhere it to the back of the camera - so I can still remove it to gain access to the wiring, and to fit new batteries when required.
This seems to to have fixed the ‘electric eye’ that controls the shutter speed / exposure, but the results have been coming out a little dark - so some tweaking is needed.