User Manual

MT-4E VHF & UHF Receiver & Transmitter Instruction Manual
IM08-MT-4E-TXRX Project 1106
Hardware Tuning and Troubleshooting
17
Receiver Main Board
Check the following test points on the receiver Main Board:
Test Point Signal Monitored Typical Voltage
TP1 Voltage from motherboard +13.8 VDC line +10 to +17 VDC
TP2 Regulated +9.5 VDC from motherboard +9.5 VDC ± 5 %
TP9 Switched +13.8 VDC line from front panel switch +10 to +17 VDC
TP37 +6.0 VDC supply +6.0 VDC ± 5 %
TP38 -6.0 VDC supply -6.0 VDC ± 5 %
TP54 +3.3 VDC supply +3.3 VDC ± 5 %
TP55 +1.2 VDC supply +1.2 VDC ± 5 %
TP56 +1.8 VDC supply +1.8 VDC ± 5 %
TP57 +2.5 VDC supply +2.5 VDC ± 5 %
TP58 +5.0 VDC supply +5.0 VDC ± 5 %
Test Points are shown on the MT-4E Receiver Jumper and Test Point Locator Illustrations.
If the test point voltages are within the specied range the following tests further verify that the
Receiver Main Board may not be the source of problem.
Apply an IF signal of frequency 21.4 MHz at a level of -30 dBm to the Receiver Main Board IF Input
SMB connector as shown on the MT-4E Receiver Top Component View (2). If the signal is properly
demodulated it proves that the Receiver Main Board and UDB are in working condition. Proceed to
the following step: