I haven't examined a recent DVD PCB, but it could be that an overvoltage has taken out a protection diode. If that's the case, then there may be a simple, no-cost DIY solution.
See
http://www.users.on.net/~fzabkar/HDD/TVS_diode_FAQ.html
HDDs have 12V and 5V TVS diodes which go short circuit when the drive experiences a sustained overvoltage.
If you could supply a photo of the component side of your DVD/CD PCBs, I may be able to identify the component for you, assuming it exists.