I wrote about the zinc-air 675 batteries in another thread. These are 1.4v and works fine as substitute for PX (in my OM1, Canonet, Lunasix etc.). Google and you can find lots of articles about zinc-air batt as substitute (even for C35). Cheap too. Go to Sim Lim Sq/Tower or any large Guardian pharmacy (e.g. Harbour Front 2nd floor) to get...
For example, a shop (called Sin Li Ho I think) on 2nd floor in Sim Lim Sq (up escalator, go straight and turn to back alley, 1st small shop selling various electrical DIY stuff) sell 6 pieces of zinc-air 675 batteries for $7.90; brand is UNICELL (made in S'pore I think).
Ah, probably the usual worn battery wire/contact etc. Common for K C35: google and you will know. Tought to fix, but if you are good with soldering you might revive it.