CD Unit testing
If you carry out any repair work on your CD unit, or just want to check it, it's worth testing it. Obviously if you have been using it for hours on end with no problems then there is a good chance that there are no problems with it. However this may not be the case.
A test which I have used to ensure correct operation is to run a CinePak based CD through the unit for a long period of time. The CD I have used for this at present is the "StarCat JagFest CD", this is the 2nd home-brew CD to use the recently found CD Keys. This makes a good test CD as it is nothing BUT CinePak, and it loops indefinitely.
Why is CinePak a good test? Simple, reading Data from a CD isn't an exact science as such, hence CD's tend to have a lot of extra data included with the data stream to correct for reading errors, this is exactly the same for a CD containing game data or game code. The problem arises with CinePak in the fact that the unit is constantly reading data at or near it's maximum data-rate, so any errors in reading can be a problem, as there is very little chance to re-read the data. Also an error in the video stream will make quite a big mess to the output. So if you can watch a CinePak CD for a long period of time with no problems, your CD Unit is happy, if it works for only a short while then there is something upsetting it, which could also affect normal game usage.
In my own testing I have found that the same StarCat CD works without issue on one unit, another unit refuses to run it for more than a few minutes, another wouldn't boot it at all. This is NOT a fault with the StarCat CD. I have one of these CD's and tried it on several units, it works perfectly well on a well functioning CD Unit, on a partially working unit, it has lasted for an hour or so before I have seen a problem. This is due to the high content of CinePak data being read at the unit's maximum throughput. I suspect the laser power/tuning may need to be adjusted for such units, however i have not yet had time to experiment with this, so try it if you like, I will post a guide when I have time and have tested this myself.
Remember, test your CD Units! It's worth doing. If you do get a problem with a disc don't jump to the conclusion the disc is at fault, try it in someone else's unit that you know is good, or a few. Only after it fails exactly at the same point on several units can you really be sure the disc is at fault.
NB, It has been brought to my attention that people are complaining that StarCat is selling defective JagFest CD's. THIS IS NOT TRUE, if you are having problems playing your StarCat CD it is most likely an issue with your CD unit NOT the CD. I have one of these well produced CD's and it refused to boot on one of the units I have been working on, but works PERFECTLY on other units which I know are good. I will investigate causes and solutions to why the units are not playing the disc correctly and report on it here when I have something to report. Until then please, don't start accusing StarCat of producing bad CD's, it's simply not the case.