If it works with a difrent battery, battery is bad
-
-
Next, try without the compact flash card, it works without the card, need a memory card
-
-
Clean the contacts on your old lens and try again with that lens, it does it with that with no CF card, the compact flash is no good and needs to be replaced
-
-
Use a different lens and try it, and after you confirm it works with the other lens, try cleaning the contacts on yours, if it still acts up, it needs a lens
-
-
If you still have trouble, it's hardware, and yes, repair is possible, but DSLR's re a PITA to fix unless you have patience
+
Error 99 is vague. This error is used for a lot of Canon DSLR errors, so it is hard to pinoint quickly. This could be the battery, memory card or a shutter failure.
+
First, try a new CF card, and then run it without that one. If it doesn't crap out, it was the card.
+
The next thing to try is the battery. Replace the battery and try again.
+
Now, before we consider the camera dead try cleaning the lens contacts, or using a different lens as a last resort to the problem. If cleaning the contacts and replacing the lens does not work, the shutter went bad. Sadly, this isn't an easy fix for most people so you will likely have to go to a shop. It is possible, but you are tearing the whole camera down since Canon didn't intend for this to last more then 50k actuations due to the class of camera this is.
+
Due to the age of the 20D if it is a body fault, I would consider the camera EOL unless you need to keep it in service and just get a lower end one to match this if you were fine with the 20D so long.
If it works with a difrent battery, battery is bad
-
Next, try without the compact flash card
+
Next, try without the compact flash card, it works without the card, need a memory card
-
Clean the contacts on your old lens and try again with that lens, it does it with that lens after that, the lens is destroyed
+
Clean the contacts on your old lens and try again with that lens, it does it with that with no CF card, the compact flash is no good and needs to be replaced
-
Try with no lens and the body cap on, and a different lens
+
Use a different lens and try it, and after you confirm it works with the other lens, try cleaning the contacts on yours, if it still acts up, it needs a lens
If you still have trouble, it's hardware, and yes, repair is possible, but DSLR's re a PITA to fix unless you have patience
I will walk you through troubleshooting
Try a new battery first
Next, try without the compact flash card
Clean the contacts on your old lens and try again with that lens, it does it with that lens after that, the lens is destroyed
Try with no lens and the body cap on, and a different lens
If you still have trouble, it's hardware, and yes, repair is possible, but DSLR's re a PITA to fix unless you have patience