Furuno FR-1710 manual Advanced-level troubleshooting con’t

Table 3-7 Advanced-level troubleshooting (con’t)

Problem	Check point and	Remedy
	probable cause
Interference rejector	1. SPU Board	1.	Replace SPU Board.
inoperable (interference	2. Mother Board	2. Replace Mother Board.
rejection level not displayed)
Echo stretch ineffective	1. SPU Board	1.	Replace SPU Board.
(Neither "ES1" nor "ES2" is
displayed.)
Only 2 parallel index lines	1. Incorrect setting of index	1.	Set index line interval referring to
(6 lines wanted)	line interval		paragraph 1.27.
Range rings are not	1. Adjust the brilliance of	1.	Replace associated circuit board if
displayed.	range rings with the		unsuccessful.
	intensity is increased.
	2. SPU Board	2. Replace SPU Board.
Poor discrimination at range	1. Sea clutter control not	1.	Improper setting of A/C SEA
	functioning properly.		control. If A/C SEA is seen only
			at very close range, suspect
			inaccurate frequency of
			crystal oscillator.
True motion presentation not	1. Poor contact of MODE	1.	Try to press MODE key a little
working correctly.	key.		harder.
	2. Selection is not accessed.	2. Press MODE key until "TM"
			appears.
	3. Speed entry is incorrect.	3. Enter correct own ship speed
			referring to paragraph 1.12.
	4. TM display inaccurate	4. Make sure that speed and compass
			inputs are accurate.
Target not tracked correctly	1. Poor definition of targets in	1.	Adjust A/C SEA and A/C RAIN
	sea clutter		controls referring to paragraphs
			1.14 and 1.15.

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