Yaesu FL-2100Z linear amplifier

This amplifier was purchased new and has remained in my possession ever since. From new, I changed the transformer secondary high voltage HV tap from 850 volts to the 620 volt tap to lower the nominal DC plate voltage from 2400 volts down to 1800 volts approximately. Dropping the plate voltage has reduced thermal stress and anode dissipation and has significantly increased the operational lifetime of the 527Bs and has helped reduce thermal stress and component fatigue. It has also significantly reduced the liklihood of arcing and flashover. Consequently, the valves are in good condition and produce the required output for Australian amateur requirements.
Despite owning this amplifier for many years, it has not had significant use over this period. The only issue it has ever had is associated with the small SWR coupler on the output side. This has been removed but has not at all effected the tuning of the amplifier. The use of an external SWR/power meter achieves the same result without issue.