Maintenance
MT930B
Service Manual
Page 6-9
LNB Power Voltage Measurement (@ RF Input Connector)
Measurement Conditions:
•
LNB: ON (13 V or 18 V)
•
Terminals: J101, J102, J103, or J104
Measurement Procedure:
1. Set the LNB to 18 V.
2. Connect a 75
Ω
load to J101, and set the load so the current is 500 mA.
3. Measure the LNB voltage at J101 (High 500 mA).
4. Set the LNB to 13 V.
5. Connect a 75
Ω
load to J101, and set the load so the current is 300 mA.
6. Measure the LNB voltage at J101 (Low 300 mA).
Measurement Specification:
−−−−
LNB Power Voltage:
•
High 500 mA:
≥≥≥≥
18.0 <20.0 V
•
Low 300 mA
≥≥≥≥
12.7
<
14.0 V
LNB Trip Current Measurement
Measurement Conditions:
•
LNB: ON, 18 V
•
Terminals: J101, J102, J103, or J104
Measurement Procedure:
1.
Set the LNB to 18 V.
2.
Connect a 75
Ω
load to J101
3.
Raise the load current by varying the load, and measure the current value
when the LNB voltage flickers.
Measurement Specification:
−−−−
LNB Trip Current:
≥≥≥≥
500 mA,
≤
800 mA
Summary of Contents for mt930b
Page 3: ...MT930B Service Manual Page i ...
Page 10: ...General Information Page 1 4 Service Manual MT930B THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 22: ...Controls and Connections Page 3 4 Service Manual MT930B THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 86: ...Options Maintenance Page 7 2 Service Manual MT930B THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 90: ...Drawings Page 9 2 Service Manual MT930B 10264 Figure 9 1 MT930B Block Diagram 1 ...
Page 91: ...Drawings MT930B Service Manual Page 9 3 10265 Figure 9 2 MT930B Block Diagram 2 ...
Page 92: ...Drawings Page 9 4 Service Manual MT930B 10266 Figure 9 3 MT930B Block Diagram 3 ...
Page 93: ...Drawings MT930B Service Manual Page 9 5 10267 Figure 9 4 MT930B Block Diagram 4 ...
Page 94: ...Drawings Page 9 6 Service Manual MT930B 10268 Figure 9 5 MT930B Head Phone Schematic ...
Page 95: ...Drawings MT930B Service Manual Page 9 7 10269 Figure 9 6 MT930B RF PC Board Schematic ...
Page 96: ...Drawings Page 9 8 Service Manual MT930B 10270 Figure 9 7 MT930B Converter Module Schematic ...
Page 97: ...Drawings MT930B Service Manual Page 9 9 10271 Figure 9 8 MT930B Main PC Board Sheet 1 of 3 ...
Page 98: ...Drawings Page 9 10 Service Manual MT930B Figure 9 9 MT930B Main PC Board Sheet 2 of 3 ...
Page 99: ...Drawings MT930B Service Manual Page 9 11 10273 Figure 9 10 MT930B Main PC Board Sheet 3 of 3 ...
Page 100: ...Drawings Page 9 12 Service Manual MT930B 10274 Figure 9 11 MT930B Power Supply Schematic ...
Page 101: ...Drawings MT930B Service Manual Page 9 13 10275 Figure 9 12 MT930B IF Filter Block Schematic ...
Page 102: ...Drawings Page9 14 Service Manual MT930B 10276 Figure 9 13 MT930B Audio IF PB01 Schematic ...
Page 103: ...Drawings MT930B Service Manual Page 9 15 10277 Figure 9 14 MT930B Audio Out Schematic ...