Troubleshooting Flow Chart
UHF1 (400
–
470 MHz)
32
[5] R368 and R370 have no soldering defects.
6.3
TX Circuit
Check TX circuit
Power supply is
normal?
Check the power
supply circuit
No
Current is normal?
[1]
Yes
Check PA matching
circuit, antenna
switch, and low-pass
circuit, etc
Yes
Control voltage is
normal? [2]
Check U801
No
No
TX VCO is
normal?[3]
Yes
Refer to
troubleshooting flow
chart of FGU circuit
No
Power of Q801 is
normal?[4]
Yes
Check Q801 and
relevant
components
No
Power of Q805 is
normal?[5]
Check Q805 and
relevant
components
Yes
No
Power of Q804 is
normal?[6]
Check Q804 and
relevant
components
No
Power of Q802 and
Q803 are normal?[7]
Check Q802, Q803,
and relevant
components
End
No
Yes
Yes
Yes
Description of normal situations:
[1] In analog mode, the current is above 4 A under 25 W, above 7 A under 45 W, and 1 A under 5 W.
However, in digital mode, the current will be reduced by 50%.
Содержание MD78X
Страница 1: ...DIGITAL MOBILE RADIO SERVICE MANUAL...
Страница 5: ...UHF1 400 470 MHz...
Страница 14: ...UHF1 400 470 MHz Exploded View and Packing Guide 7 3 2 Packing Guide...
Страница 56: ...UHF1 400 470 MHz Interface Definition 49 Pin No Name Description 39 GND Grounding 40 PWB_IN Power On Off signal...
Страница 62: ...55 9 PCB View MD78X MD78XG PCB View Front Panel Top Layer...
Страница 63: ...56 MD78X MD78XG PCB View Front Panel Bottom Layer...
Страница 64: ...MD78X MD78XG PCB View Main Board Top Layer 57...
Страница 65: ...MD78X MD78XG PCB View Main Board Bottom Layer 58...
Страница 111: ...UHF2 450 520 MHz...
Страница 120: ...UHF2 450 520 MHz Exploded View and Packing Guide 7 3 2 Packing Guide...
Страница 167: ...54 9 PCB View MD78X MD78XG PCB View Front Panel Top Layer...
Страница 168: ...55 MD78X MD78XG PCB View Front Panel Bottom Layer...
Страница 169: ...MD78X MD78XG PCB View Main Board Top Layer 56...
Страница 170: ...MD78X MD78XG PCB View Main Board Bottom Layer 57...
Страница 216: ...UHF3 350 400 MHz...
Страница 225: ...UHF3 350 400 MHz Exploded View and Packing Guide 7 3 2 Packing Guide...
Страница 272: ...54 9 PCB View MD78X MD78XG PCB View Front Panel Top Layer...
Страница 273: ...55 MD78X MD78XG PCB View Front Panel Bottom Layer...
Страница 274: ...MD78X MD78XG PCB View Main Board Top Layer 56...
Страница 275: ...MD78X MD78XG PCB View Main Board Bottom Layer 57...
Страница 321: ...UHF5 806 941 MHz...
Страница 330: ...UHF5 806MHz 941MHz Exploded View and Packing Guide 7 3 2 Packing Guide...
Страница 376: ...53 9 PCB View MD78X MD78XG PCB View Front Panel Top Layer...
Страница 377: ...54 MD78X MD78XG PCB View Front Panel Bottom Layer...
Страница 378: ...55 MD78X MD78XG PCB View Main Board Top Layer...
Страница 379: ...56 MD78X MD78XG PCB View Main Board Bottom Layer...
Страница 414: ...VHF 136 174 MHz...
Страница 423: ...VHF 136MHz 174MHz Exploded View and Packing Guide 7 3 2 Packing Guide...
Страница 468: ...PCB 52 9 PCB View MD78X MD78XG PCB View Front Panel Top Layer...
Страница 469: ...PCB 53 MD78X MD78XG PCB View Front Panel Bottom Layer...
Страница 470: ...MD78X MD78XG PCB View Main Board Top Layer 54...
Страница 471: ...PCB 55 MD78X MD78XG PCB View Main Board Bottom Layer...