3.ADJUSTMENT

3.1 Checking magnetron heater voltage

Magnetron heater voltage is formed on the MD Board (03P9235) of the antenna unit, and is preadjusted at the factory for use with any length of signal cable. Therefore no adjustment is required. However, check magnetron heater voltage as follows:

1.Turn on the radar and leave it in stand-by.

2.Open the antenna cover.

3.Unfasten four screws to remove the RF section cover.

DANGER

ELECTRICAL SHOCK HAZARD

This check is done with the power on DO NOT touch the magnetron.

Magnetron

Four screws

Figure 3-1 Antenna unit, cover opened

4.Connect a multimeter, set to 10 VDC range, between test point J825#4 and J825#6 (GND) on the RTB Board (03P9249).

Measure voltage at this connector (J825).

Figure 3-2 Antenna unit, cover opened

5.Confirm the meter reads 7.6 V ± 0.1 V.

6.Close the antenna cover and tighten the cover fixing screws.

3-1

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Furuno 851 MARK-2 installation manual Adjustment, Checking magnetron heater voltage