AMX TXC16 Plus Specifications download pdf (Page 154)

SG-2000 MANUAL 147

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

then put through the USB filter to get rid of inter-modulation and the other

sideband. Both upper and lower sidebands can be sent through this filter by

changing the mixing schemes through out the radio with an offset equal to the

USB filter bandwidth.

This signal is then bumped up to the IF frequency between 82 and 86 MHz

(along with a re-injected 10.7 MHz for carrier for A3A and A3H modes only).

The 82 MHz filter is used to attenuate the LO frequency and other

miscellaneous signals outside its range. The signal is then amplified and mixed

down to the RF frequency. A 30 MHz filter band-limits the signals going out

before the transmit buffer increases the transmit level to the level needed to

drive the LPA.

23.1.3 Test Setup

Make a visual inspection. Look for quality defects. Check all electrolytic

capacitors, diodes, transistors, IC's, solder bridges, etc.

Use the multimeter in the Ohms position. Check for short circuits on the main

and regulated power lines: 5VG, 8VG, 10VG, 10VRX, 10VTX, 13.6VSW and

13.6V unswitched.

Connect extender cable from J15 on the Test Chassis to J506 on the exciter

board under test.

Connect extender cable from J1 on the Test Microprocessor board to J501 on the

exciter board under test.

Plug SG-2000 Head into J503 or J504 connector.

Apply power to the exciter by pressing the "POWER" button on the Head and

turn radio on.

Using the multimeter test each test point for the following voltages.

TP501 8VG

TP502 10VG

TP503 5VG

TP504 10VRX

Program the frequency 15.0 MHz into the head to verify if head displays data

and there is interaction between radio and head. Refer to operating

instructions for programming procedures.

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AMX TXC16 Plus Specifications Page 154