My commiserations and short of a full examination of it you may not get to the bottom of it.Even then it might be difficult to identify the exact problem

The conclusion I'd draw is that unless a clearly fixable fault is identified the camera is only fit for the bin but that's just me. You may like the uncertainty and never knowing which future frames will be totally defective and no, I am not trying to be sarcastic. It seems to me that anything Lomo has that attraction of uncertainty for those who enjoy that

It won't come as any surprise that I won't be joining that club any time soon