JVC KS-FX725R service manual Conditions

KS-FX725R

Item	Conditions	Adjustment and Confirmation methods			S.Values			Adjust
1. Head	Test tape:	Head height adjustment
azimuth	SCC-1659	Adjust the azimuth directly. When you
adjustment	VT703(10kHz)	adjust the height using a mirror tape,
		remove the cassette housing from the
		mechanism chassis. After installing the
		cassette housing, perform the azimuth							A line
		adjustment.
		1. Load the SCC-1659 mirror tape. Adjust with
		height adjustment screw A		and azimuth	Head shield
		adjustment screw B so that line A of the			The head is at low position
		mirror tape runs in the center between Lch
					during.
		and Rch in the reverse play mode.
		2. After switching from REV to FWD then to							B line
		REV, check that the head position set in
		procedure 1 is not changed. (If the position
		has shifted, adjust again and check.)
		3. Adjust with azimuth adjustment screw B so			Head shield
					The head is at High position
		that line B	of the mirror tape runs in the		during REV.
		center between Lch and Rch in the forward
		play mode.			Output
		Head azimuth adjustment			level:
		1. Load VT724	(1kHz) and play	it back in	Maximum
						PBHead
		the reverse play mode.
		Set the Rch output level to max.			FWD Adj B
		2. Load VT703 (10kHz) and play it back in
		the forward play mode. Adjust the Rch
		and Lch output levels to max, with
		azimuth adjustment screw B. In this case,
		the phase difference should be within 45 .			REV Adj C		HEIGHT Adj A

3.Engage the reverse mode and adjust the output level to max, with azimuth adjustment screw C.

(The phase difference should be 45 or

more.)	phase
(0 )	(45 )

4.When switching between forward and reverse modes, the difference between channels should be within 3dB. (Between FWD L and R, REV L and R.)

5.When VT721 (315Hz) is played back, the level difference between channels should be within 1.5dB.

2. Tape speed	Test tape: VT712	1.	Check to see if the reading of the F, counter /		Tape speed: Built-in volume
and wow	(3kHz)		wow flutter meter is within 3015 3045(FWD		3015	resistor
flutter			/ REV), and less than 0.35% (JIS RMS).		3045Hz
confirmation					Wow
		2.	In case of out of specification, adjust the		flutter: less
			motor with a built-in volume resistor.		than 0.35%
3. Play back	Test tape: VT724	1.	Play test tape VT724, and set the volume		Speaker out
frequency	(1kHz)		position at 2V.		1kHz / 63Hz
response	VT739		Play test tape VT739 and confirm.		: 0	3db
confiramation	(63Hz / 1kHz / 10kHz) 2.				1kHz / 10kHz
			1kHz / 10kHz: -1	3dB,	: -1	3db
			1kHz / 63Hz: 0	3dB,

3.When 10kHz is out of specification, it will be necessary to read adjust the azimuth.

The tuner section is of an adjustment-freedesign. In case the tuner is in trouble, replace the tuner pack.

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