CD/DVD Player reports "damaged" disk
mid 2010 iMac 27" Yosemite. Mac OS 10.10.5
My internal DVD player now reports almost all DVDs that I insert as damaged and it skips over large sections or even the entire disk. I put the same disk into my wife's Mac Book Pro and it plays flawlessly. Is there any home remedy for my internal disk player? Is there an economic way to either repair it or replace it? Should I visit Apple store or find a non-Apple repair shop? Any recommendations in Palo Alto? Should I shop for an external DVD/CD player with USB or firewire connectivity? My wife's computer has the same operating system but is about a year older. We watch a lot of DVDs from the library on my iMac.
iMac, OS X Yosemite (10.10.3), 27"