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The display being dim may signify a reduced power supply voltage.
That could also lead to the second odd behavior - the lower-than-specification voltage upsetting the control circuitry and inducing the 'panic' behavior you describe.
Do you have a voltmeter and do you know how to take measurements with it? and does the 'technical manual' show voltage levels expected at various points?
If so, testing those points is advisable. If you can, and do, let me know the results.
If you cannot so test the device, then would you consider sending it out, or taking it to a nearby servicing facility ? if so, let me know your local zip code, or town/city and state/region, and I will look up contact info and procedure info.