AMX TXC16 Plus Specifications download pdf (Page 159)

SG-2000 MANUAL 152

The SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA

23.1.8 SSB Alignment

See setup test schematic.

Reduce the AGC response to a minimum by turning R286 fully clockwise.

Inject at SG-2000 RF In/Out 10 µV (or less if the audio out on J103 looks

distorted) of 10,001.0 KHz.

Turn the radio on and program in the frequency 10,000.0 KHz A3J, USB, VOC,

SPK modes. You should be able to hear the 1 KHz tone difference between the

two frequencies and read it on the oscilloscope. If not, refer to the trouble-

shooting section.

Adjust T404 for 200 mVpp on IC202 pin 10.

Monitor the dB-meter attached at J301 and maximize the signal by adjusting

R238, T202, T201, T105, C160, T106, T107, T108 and L121 to L127. Pass through

the tuning of the 82 MHz filter a few times to obtain the maximum signal

strength. Reduce the RF In to .5 µV and note the dB level at J301.

Switch SW1 to GND position and note the dB level at J301. It should read -20 to

-25 dB (.08-.05 VRMS). The difference between the .5 µV RF In reading and no

RF In reading should be =15 dB. If not, repeat steps above or refer to the

troubleshooting section.

Turn the power supply off

Solder the surrounding shield on the 82 MHz filter with a bead of solder all

around. Note: keep the top shield positioned on top of the surrounding shield

for better positioning of holes, but do not solder together the two shields yet.

Change RF In to 11,000.9 KHz and the radio to 10,999.9 KHz. You should be

able to hear and monitor on the dB meter and scope the 1 KHz tone difference.

Adjust T106, T107 and T108 for maximum indication on the dB-meter. Note the

dB level and compare it with the level read at 10,000.0 KHz. It should be within

1.5 dB difference.

Repeat the two steps above for 10,011.0 KHz on the RF Generator and 10,010.0

KHz on the radio.

If the three dB readings from 10,000.0 KHz, 10,010.0 KHz and 10,999.9 KHz are

not within 1.5 dB difference, and the S/N ratio is not =15 dB (>10 dB for Rev E

boards and earlier), repeat this procedure or refer to the troubleshooting

section.

Change modes to A3A, CW, A3J. There should not be any difference in the

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AMX TXC16 Plus Specifications Page 159