Mac Mini Doesn't Recognize DVD/CD media

Question

I've tried most of the suggestions given on the boards, including the SMU reset, but my Mac Mini still has problems with burned CD's and trying to burn DVD's. I've tried several different brands of DVD media and the DVD's just get kicked out. On the CD side, I load a burned disc from another machine it just shows up as a blank disc. I'm running Leopard 10.5.3 on this machine. Any ideas?
Rich
Model Name: Mac mini
Model Identifier: Macmini1,1
Processor Name: Intel Core Duo
Processor Speed: 1.66 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 2 MB
Memory: 2 GB
Bus Speed: 667 MHz
Boot ROM Version: MM11.0055.B08
SMC Version: 1.3f4
MATSHITA DVD-R UJ-846:
Firmware Revision: FM3J
Interconnect: ATAPI
Burn Support: Yes (Apple Shipping Drive)
Cache: 2048 KB
Reads DVD: Yes
CD-Write: -R, -RW
DVD-Write: -R, -RW, +R, +R DL, +RW
Write Strategies: CD-TAO, CD-SAO, DVD-DAO
Media: Insert media and refresh to show available burn speeds

Answer 1

The fact you're having problems with both DVDs and CDs is not a good sign, since it is more likely to mean a faulty drive than if one or other media were problematic, but the other worked OK.
Do you get any error messages when you insert a blank DVD or burn a CD?
One thing you might want to try is to use a lens cleaner on the drive since the slot loading drives are a little more prone to dirt and debris than tray loaders. Normally if a head is dirty you'd be able to work with one media but not the other, so the fact both are troublesome either means it's not a simple matter of a dirty head or that the drive is significantly contaminated.
If the lens cleaner doesn't help, I think the symptoms suggest the drive itself has problems. In that instance, it may be a loose connector, or that it needs to be replaced. If the latter, I'd normally suggest an external drive for greater flexibility and better performance - typically at a not much different price than an internal drive, but obviously not then requriring any service time of cost.