I bought a used cannon powershot a300. i had tried

try changing the memory storage device for a new/different one (often an SD card - I don't know for the A470) Just a suggestion. I doubt your pacemaker has anything to with it (do ther pepe when using your camera experience the same picture loss ?).

14.July.2014

http://www.usa.canon.com/cusa/support/consumer/digital_cameras/powershot_g_series/powershot_s100#ServiceAndSupport

This is the page for your camera at canonusa.com.

One can download brochures and manuals for this camera.

The information you require is on this page or linked to it.

Good luck on it.

Same problem but with a different camera. Turns out, these cameras are very... may I emphasize very... picky as to which cards to use. Try other off-brands and you'll be surprised as to what it takes.

Try cleaning the contacts on the card.

This camera does not take SD cards. Only CompactFlash cards will work.

Try using a different USB cable. The connections between cameras and computers usually are problematic. A card reader will allow you to download the pictures from the SD card, without problems and saving your camera's battery power supply

Buy a card reader for cheap and download photos using card reader. Remove SD card from camera and insert into card reader, then hookup card reader to computer through USB port. Try Picasa3 free software from Google to download images. Works great and all is inexpensive

http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&tabact=SupportDetailTabAct&fcategoryid=221&modelid=9828#ModelTechSpecsAct




CompactFlash (CF) Card Type I

Try setting your camera to mass storage instead ptp.
Reinstall the software of canon.Also see if the camera is in transfer mode rather in shooting mode.
Check if your card is accidently locked somehow.
Always try to load original driver cd and software that came with the camera.
KAMAL GO
[email protected]

This sounds like it might be a defective CCD imager. If so, Canon should fix this for you for free, including free shipping both ways. This is regardless of your camera's warranty status. Please check the following two links for more info:
http://camerarepair.blogspot.com/2007/11/canon-digital-cameras-showing-black.html
http://www.usa.canon.com/consumer/controller?act=PgComSmModDisplayAct&fcategoryid=225&modelid=13390&keycode=2112&id=29819
Applicable cameras include:
A40, A60, A70, A75, A80, A85, A95, A300, A310, S1 IS, S60, S200, S230, S330, S400, S410, S500, SD100, SD110, IXUS V2/300/400/430/500, IXY Digital 200a/300a/400/450/500