Realistic HTX-100 Service Manual page 13

ALIGNMENT OF TRANSMITTER PORTION
1. Test Equipment Required
DC Power Supply (13.8 V) more than 10 A
AF Signal generators (Two required)
RF SSVM
DC Ampere Meter
AF SSVM
Key Switch
2. Preparation for Alignment
Oscilloscope 1 , 2
RF Power Meter
Dummy Load (50 ohm and 8 ohm)
VR 5, 6 Counterclockwise VR 11 Counterclockwise
VR 12 Clockwise TX/RXSW RX
FREQUENCY : 29.000 MHz
3. Alignment Procedure
Step Preset to Adjustment Remarks
Mode: SSB
Remove the B001 (PB-1 00) from Main PCB.
1
No modulation
VR12 Connect a DC Ampere meter(+) to TP 6, (-)to TP 5.
Adjust VR 11 for 50 rnA reading on the DC Ampere meter.
2 Same VR 11
Connect the DC Ampere meter(+) to TP 6, (-)to TP 4.
Adjust VR 12 for 50 rnA reading on the DC Ampere Meter.
Disconnect the DC Ampere meter. Reinstall the B001 to the
Main PCB.
OSC 1:500 Hz Connect a RF Power meter to the Antenna jack and then, con-
3
OSC 2: 2400 Hz
L26
nect a RF SSVM, an oscilloscope across a RF dummy load to
S1, S2: ON
the RF power meter.
Mode:SSB Adjust L 26 for maximum reading on the RF SSVM.
During this step, set the AF S.G. so that the output is less than
20 Vp-p. Repeat this step two times.
Adjust level of OSC 1 and OSC 2 for 30 mV reading on the AF
4 Same VR5 SSVM, then adjust VR 5 for 36 Vp-p reading on the oscillo-
scope.
Pull RF Gain Adjust level of OSC 1 and OSC 2 for 30 mV reading on the AF
5 Control VR6
SSVM, then adjust VR 6 for 16 Vp-p reading on the oscillo-
(Low Power) scope.
6
osc
1,
osc
2:
VR4
Adjust VR 4 so that the carrier leakage at SSB and CW be-
OFF come minimum and almost equal.
7 Same as step 3. VR9
Adjust level of OSC 1 and OSC 2 for 30 mV reading on the AF
SSVM, then adjust VR 9 so that "9" LED just lights on.
Mode: CW
Connect an AF SSVM across a dummy load (8 ohm) to EXT
8
No modulation
VR13 jack. Connect a key switch to the Key jack. With Key switch
ON, adjust VR 13 for 0.2 V reading on the AF SSVM.
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