Protection Circuits - Tokyo Hy-Power HL-1.5KFX User Manual

10. Protection Circuits

There are five major protection functions in this amplifier. If the amplifier has shut down for some
reason, before re-setting, correct the possible cause of the shut down. Turn off the POWER once
and back on to reset.
10-1 O.DRIVE (Over Drive/ Band Miss-set)
When the drive power exceeds the 100W level, the amplifier will shut down to STAND-BY mode (or
receive) in order to protect the input side of the power FET's. This protection might also activate if the
band is set wrong. This usually occurs, in MANUAL BAND mode, when the amplifier band setting is
lower than that of the transceiver. To comply with FCC rules any RF between 26.0-28.0MHz will cause
Amplifier to shut down and not operate.
10-2 O.HEAT (Over Heat)
When the temperature of the aluminum heat sink in the power amplifier reaches 70 degrees C, the
amplifier defaults to RECEIVE mode to protect the power FET's. Likewise, if the temperature of the
inside layer of the power transformer reaches 130 deg. C, the amplifier will default to RECEIVE mode for
your safety. O.HEAT protection cannot be reset until the heat sink or transformer has sufficiently cooled
off.
10-3 O.VOLT (Over Voltage)
If there is a sudden AC line voltage spike, or if the transformer primary develops a fault, the FET drain
voltage may rise above acceptable levels. If O.VOLT protection trips, check the AC line voltage with a
circuit tester or an AC voltmeter.
10-4 FUSE (Fuse Blown)
If either of the glass fuses (20A) on PC1662V fails, O.VOLT protection activates. Under normal usage of
the amplifier, this failure should rarely (if ever) occur. If it occurs, there is a possibility that the power
FET's have failed together. If the amplifier cannot be reset, consult with the dealer or the service center.
10-5 PR (Reflected Power Protection)
If reflected power because of the antenna reaches approximately 80W, the PR protection may trip. If it
does, one solution is to reduce the drive power from the transceiver. Or you may need to check that your
antenna match (SWR) is still ok. If the match cannot be corrected and the antenna system isn't faulty,
use an antenna tuner.
As noted above, the amplifier is equipped with several kinds of fast acting protection circuits
using the latest in microprocessor technology. However, if the amplifier is operated in such a
manner that multiple protections work repeatedly over a long period of time, the amplifier can be
seriously damaged.
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