AMERITRON AL-1500 Gebrauchsanweisung - Seite 10

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CW PROCEDURE

Follow these instructions in numerical order. If the various meter

readings are different than indicated, check the connections from

the exciter to the amplifier and make sure they are correct.

Consult the manual for the exciter.

Be sure the transformer is correctly installed and wired for your

line voltage. See the "Transformer Installation" section on page 4

and 5 for wiring details.

Set the AL-1500 front panel switches as follows:

POWER TO OFF

OPR-STBY TO STBY

SSB-CW TO CW

MULTIMETER TO HV

2. Plug the AC line cord into the proper voltage outlet.

3. Set the Power Switch to the ON position. The grid meter

should light and the blower should start. After three minutes,

the plate meter should light and the multimeter should read

3600 volts nominal and absolutely no more than 3700 volts

HV.

4. With the amplifier still on STANDBY. tune the exciter into a

normal 50 ohm load according to the manufacturer's

instructions. Turn the exciter drive fully down after tuning.

5. Place the amplifier mode switch in the CW position, the

bandswitch on the same band as the exciter, the PLATE

control in the dial range for the band selected and the load

control as indicated:

6. With exciter drive still at zero, place the MULTIMETER

switch in the Ip position. Observe the 1000 mA scale. The

meter should read zero (0). Place the STBYOPR switch in

the OPR position.

7. Key the exciter (no drive) and observe the plate current on the

1000 mA scale. It should be 75 mA. Place the CW-SSB

switch in the SSB position. Plate current should now read

250 mA. Return the CW-SSB switch to the CW position.

Note: The no drive currents will vary up to 25% due to

component and line voltage tolerences.

8. Apply only enough drive to indicate a grid current of 50 mA or

an Ip of no more than 500mA. Tune the PLATE control for

maximum output power or grid current. It is normal for the

plate current to dip at this point.

goes over 100 mA. reduce the drive at once. Unkey the

exciter.

NOTE: This amplifier has a circuit that protects

the tube from excessive grid current. If 175 mA of peak grid

current is reached, the "OPR" LED will no longer light and

the amplifier will go into a bypass condition. This overload

condition can be reset by momentarily putting the

STBY/OPR switch in the STBY position. Repeated tripping

of the grid overload circuit usually indicates that the loading

control is set too far counterclockwise for the amount of

drive being applied to the amplifier or that something in the

antenna system is changing impedance (arching) during

9. Place the MULTIMETER switch in the PO position and

observe the 2000 Peak RF Watts scale. Increase the drive

until 100 mA of grid current is indicated. Adjust the LOAD

and PLATE controls for maximum output. The grid current

may be lower now.

10. Advance the drive to 100 mA of grid current. Adjust the

LOAD and PLATE controls for maximum output power. The

output should be over 1000 watts now.

11. Apply full drive without exceeding 100 mA of grid current.

The final grid current should be around 50 mA and the plate

current below 1000 mA.

If the grid current