What can cause massive overexposure on a Canon PowerShot A470?

I probably know an answer.

Cameras almost always have aperture open if not recording anything - to make the optical viewfinder brighter or electronic viewfinder display better image.

Then, cameras close aperture for each exposure to arbitrary or automatically selected F value.

Cameras know how much light will be cut if they close down to F if they know the open objective speed.

Now, if the aperture is stuck in the middle, camera will always overexpose photos when set F is bigger than initial F, and will do so even more if the aperture does not move at all.

The video mode may be unaffected because in this mode camera meters in real time, just the noise may be bumped.

I've had this problem and it is the ribbon cable to the electonic shutter that has broken. Sadly it is not an easy fix as the camera is difficult to dismantle and ribbon cables are difficult to solder.

Same issue with My Canon Powershot SX430IS. The image goes whitewashed after a particular zoom range. Just before that range there is no problem and i can hear the shutter release sound. Butter just after passing that range no shutter clicking noise and images are over exposed. There is no problem with Videos. Something to do with aperture. Went to canon Master service center. The service center seems very familiar with this issue. And for Powershot XXX series they only provide replacements, No repairs. I am out of warranty by 3 weeks. So now i have to pay RS. 8000+ for replacement. And i bought the camera 2 years back for 12999.