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As the owner of a company, I'll take the word of my greasy haired dirty shirt, butt crack showing repair guy over a self diagnostic computer any day.
I'm sure that H.S. has a system as well.
HS has a system. They use the Power light and the Ready light for self-diagnostics, and then there are three leds on the main circuit board for more detailed troubleshooting. It is a simple system, but it works great - I can fix most calls over the phone.