Originally Posted by
keebler303
Some Chinese tubes are DOA, others probably last for thousands of hours of use. I think its pretty safe to say that if it works well for a short time, you probably have good tube and it will last for a while. If you see a power dropoff or something early on, its already circling the drain. Assuming you have a good tube, you will have a gradual drop in power as the gas slowly leaks out. If you have an abrupt change in power, you probably have some type of electrical problem or a cracked optic or something. As an example in a lot of RF lasers there are two amplifiers, if one fails, you will get about half the power but it will still work. Its really a good idea to buy a power meter so that you can track the laser power and get an idea of when you should order a new one or have yours serviced. You could also buy a cheap machine and then upgrade just the laser once you make some money or get tired of changing tubes.
Matt