Chapter 4: Disassembly and Reassembly
Type 150/150G/400/400G Course Computers Service Manual 83156-1 17
Type 150/400 Course Computers
the SIL pad is punctured the power devices are likely to be blown. This test is to check
whether the SIL pad is intact.
• Using a DVM set to Ohms, touch one probe on the metal tab of the power device
and the other on the heatsink.
• Check that the resistance measured is >500K
• Repeat for all power devices along the right hand side of the PCB.
3.3. Detailed Diagnosis
Before starting testing ensure that the following are connected to the Course Computer:
• Fluxgate compass
• Rudder reference
• Control Head
• 330Ohm resistive load to the clutch terminals
• Pathfinder Display connected via NMEA 1 (do not connect the Pathfinder unit via
SeaTalk)
Unless otherwise stated, the following tests should be carried out with 12V applied to
the Course Computer
Step 1 - Power Checks
• Check the voltages at the following locations are correct:
Testpoint Measured Voltage
Type 150 Type 400
V
PWR
12V 12V
V12
12V 12V
3V
3.3V 3.3V
5V
4.9V – 5.2V 4.9 – 5.2V
VIN+12V
22.5 – 25V 22.5 – 25V
VADC
? ?
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