Just to confirm, are you having the same problem as this customer? Is your device not turning on at all? Even though it's fully charged? With a new battery? Or, with a known working, used battery?
As for the possible faulty component, we usually suggest to send us back the defective unit for further inspection. Once fully inspected, we would know what is exactly wrong with it.
Unfortunately, you cannot repair the unit by yourself as stated earlier.
The on-site inspection that the other tech support is talking about is the Pre-Paid Non-Warranty Inspection Service RMA. In other words, you would purchase this if you would like to get your out-of-warranty unit repaired.