15
CALIBRATION OF OVER-TEMPERATURE ALARM THRESHOLD
1) Short-circuit the thermal switch placed on the RF section’s heat sink.
2) Adjust the trimmer, R4, placed on the Alarms card until the over-temperature protection is
activated, and the TEMP led lights up (3.Fig.1).
3) Remove the short-circuit on the thermal switch and verify that the TEMP led goes out.
4) Repeat this procedure again to verify the correct trimmer R4 adjustment.
CALIBRATION OF VSWR
1) Connect a dummy load, 25 ohm 500W (two dummy loads 50 ohm 250W in parallel) with a by-
pass wattmeter in series (e.g., BIRD mod.43) set for reflected power reading (SETUP 2).
2) Adjust the output power of the exciter to obtain a reading of 25W of reflected power on the
external wattmeter and the PJ250 meter.
3) Adjust the trimmer, R7, placed on the Alarms card until the R.O.S. protection is activated, and the
SWR led lights up (5.Fig.l).
4) Decrease the output power of the exciter and wait for the SWR led to go out (automatic
protection cycle).
5) Increase the output power of the exciter again over the R.0.S. threshold of 25W, and verify once
again, that the SWR led lights up (5.Fig.1).
CALIBRATION OF OVER-DRIVE ALARM THRESHOLD
1) Adjust the driver power to minimum and switch on the amplifier.
2) Place the DIR/REF selector (12.Fig,l) to the REF position.
3) Connect (1.Fig.2) a non inductive dummy load 50 ohm 250W to the RF output with a through
wattmeter (e.g., BIRD mod.43) in series as shown in the SETUP 1.
4) Set the exciter power to obtain 250W on the through external wattmeter and on the PJ250 meter.
5) Increase the output power of the exciter again until a reading of 270W on the PJ250 meter is
obtained.
6) Adjust the trimmer, R21, placed on the Alarms card until the over-drive protection is activated,
and the INPUT led lights up (4.Fig.1) with immediate shutdown of the amplifier.
7) Decrease the drive power of the exciter and wait for the INPUT led to go out.
8) Increase the drive power of the exciter again over the overdrive threshold of 270W, and verify,
that the INPUT led lights up (4.Fig.1).
RF SECTION ADJUSTMENT
No adjustment is required inside the RF section because it's a factory adjusted module; if calibration is
necessary, please send the module to your local distributor.
LOW-PASS FILTER ADJUSTMENT
No adjustment is required inside the Low-Pass Filter module because it's a factory adjusted module; if
calibration is necessary, please send the module to your local distributor.
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