Galaxy
DX Radios DX98VHP
Documentation Project
CBTricks.com
Transmitter Alignment
See Alignment
Locations
SETTINGS | CONNECTION |
ADJUST
|
ADJUST FOR |
Remove
TP7-TP9 Jumper PCB.
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TX CARRIER OSCILLATORS: AM TX Mode Band E CH. 1 |
Connect Frequency Counter to TP6 |
L25
|
LSB/TX mode: Adjust for 10.6975MHz ±20Hz. |
Connect Frequency Counter to TP6 |
L24
|
USB/TX mode: Adjust for 10.6925MHz ±20Hz. | |
Connect Frequency Counter to TP5 |
L23
|
AM/TX mode: Adjust for 10.6950MHz ±20Hz. | |
DRIVER BIAS:
(IRF520 Vg) Set Radio to: Band E, Ch.1 Mode to USB MIKE GAIN at minimum. |
Connect DC Ammeter between TP7 and TP9. |
VR12
|
Key TX adjust
for 50mA. Verify 3.75vdc max.on bare lead of resistor in L37. |
FINAL BIAS: (IRF520 Vg) Set Radio to: Band E, Ch.1 Mode to USB MIKE GAIN at minimum |
Connect DC Ammeter between TP7 and TP8. ****Warning**** Setting these adjustments are critical and exceeding the maximin voltage and current settings will cause damage to the transmitter and void the warranty. |
VR10 VR11 |
Preset both VR10 & VR11 for zero mA in TX mode. Key TX & adjust for 50mA. Verify 3.50vdc max on bare lead of resistor in L34. Key TX & adjust for 100mA. (total for both VR10 & VR11) Verify 3.50vdc max on bare lead of resistor in L33. |
Replace
TP7-TP9 Jumper PCB.
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RF AMP CHAIN: Set mode to AM. Set RF power control fully clockwise. |
Connect wattmeter to ANT output. |
L44,
L43,
L42, L40, L44 |
Key TX & adjust (in order) for maximum RF output . Recheck power across
entire freq range. Re-adjust L44 for minimum SSB distortion. |
SSB CARRIER
BALANCE: Set mode to USB Set RF power control fully clockwise MIKE GAIN to minimum. |
Connect wattmeter
to ANT output. |
VR6
|
Key TX, adjust for min. carrier leakthrough on scope or wattmeter. Recheck on LSB mode. If necessary readjust for best balance of sideband suppression between LSB & USB |
SSB APC: Set mode to USB Set RF power fully clockwise. MIKE GAIN to minimum. |
Connect DC voltmeter from pcb ground to TP7 |
VR17
|
In TX, adjust for 12.5vdc |
SSB ALC:
Mode to USB. MIKE GAIN to maximum. Inject two-tone audio signal of 700Hz and 1900Hz, 30 mV to Mic input. |
Connect wattmeter
to ANT output. |
VR13
L44 |
In TX, adjust
for 200 watts PEP. Adjust for minimum distortion on scope |
AM CARRIER POWER: Set mode to AM, MIKE GAIN at minimum. RF Power SW to HI. |
Connect wattmeter to ANT output.
CAUTION! Do not exceed power levels. Damage to power transistors and inability to achieve 100% modulation from insufficient audio power will result. |
VR14 |
Set RF PWR fully clockwise adjust VR14 for 65 watts |
VR18
|
Set RF PWR fully counter clockwise.
Adjust for 10 watts |
||
RF METER:
Set mode to AM, RF Power fully clockwise MIKE GAIN at minimum. Meter Switch to PWR |
Connect wattmeter to ANT output. |
VR9
|
Adjust so meter agrees with Wattmeter. |
AMC: Mode to AM. RF Power fully clockwise MIKE GAIN to maximum. Inject audio signal of 1KHz at 30mV to Mic input. |
Connect modulation meter to ANT output. |
VR16
|
Adjust for 100% modulation depth. |
VR
PCB (EPT99HP40A) Adjustment
|
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Mod Lamp Adjust: Mode to AM. RF Power fully clockwise MIKE GAIN to maximum. Front Panel Switch to Mod Lamp Inject audio signal of 1KHz at 30mV to Mic input. |
Connect modulation meter to ANT output. |
VR406
|
Adjust so that lamp illuminates at approx. 75% modulation |
RF
Amp PCB (EPAC40010A) Adjustment
|
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Gate Voltage Adjust:
|
Connect DC voltmeter
from Amp PCB ground to gate of Q6.
Connect DC voltmeter
from Amp PCB ground to gate of Q13. |
VR2
VR3 |
4.00VDC
4.00VDC |
SWR Meter Adjust: Unkey radio PWR/SWR/RB switch to SWR.
Key radio. |
Connect wattmeter / 50-ohm resistive dummy load to ANT output. Remove 50-ohm dummy load and connect 100-ohm 100 watt load to radio antenna output connector.
|
PWR Control
VR1 |
Adjust to max (65 watts).
Adjust for 2:1 reading on radio SWR scale. NOTE: If a 100-ohm 100 watt load is not available just use 50-ohm dummy load and set VR1 for 1:1 on SWR scale. |
Disclaimer:
Although the greatest care has been taken while compiling these documents,
we
cannot guarantee that the instructions will work on every radio presented.