Overview

The basics of troubleshooting are the same whether it be troubleshooting poor vacuum, the process, or coating adhesion.

In troubleshooting, one of the real dangers is in trying to solve the wrong problem. This is why it is essential to ask questions and trust as little as possible without verification. It is all too easy to leap to easy conclusions. An example of this that I have seen happen is as follows.

A poor base pressure was immediately thought of as being caused by a leak. In the previous cycle, everything was okay and as per many previous cycles. The immediate reaction was to assume a leak and to attach a leak detector. Many hours were spent searching the system for leaks. With large or complex systems, the number of joints could be huge and this could have taken more than a few hours, in some cases many days. Over the hours, no leaks were found. The problem of the poor base pressure was not due to a leak but was eventually found to be due to the diffusion pump oil level being too low and the pump performance falling off rapidly.

The experience of this type of problem is to produce a simple list of actions that can be used to troubleshoot most problems.

1. The first essential is to question everything and trust nothing

2. Use all senses

3. Compare to the normal operation cycles and look for differences

4. Ask the question "What has been done or changed since the previous...