JVC XV-1000BK, Service Manual

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(2) Disc type judgment error (no disc, no RFENV)
* Laser is defective.
* Preamplifier is defective (IC101).
* LPF circuit is defective. Q101, R125 to R129.
* Pattern is defective. Lines for CN101"15" and "17".
Lines for IC351"41" to IC101"6" (LDON).
* DEM/ECC is defective (IC351).
* Servo IC is defective (IC301).
* Is signal sent to IC301 (servo)"78" AS2 (TP108)?
* IC101 For signal from IC101 to IC301, is signal output from IC101"11" AS1 (TP109) and
IC101"53" FRENV (TP105)?
(3) Traverse movement NG
* For automatic adjustment, traverse movement occurs only when the position is changed to retry
judging the disc type after the 1st judgment resulted in an error. Therefore, traverse movement
rarely occurs because, in most cases, disc judgment at the current position (1st time judgment)
is executed successfully. (Of course, NG rarely occurs in this step.)
Note: 1st time judgment of disc type resulted in NG. The re-judgment of disc type may not be
successful. Therefore, after removing the cause of traverse movement, re-execute automatic
adjustment and confirm that no problem exists.
* Check points
a). During stop
Whether 50% duty pulse is output to TP253
Whether W003 is at approx. 2.5VDC
Offset voltage between CN101 "34" and "35" (scores mV if exists)
b). When tray is opened or closed
Check by oscilloscope whether a rectangular wave signal is output from W003 or CN101"34" or "35".
Single-layer DVD
Double-layer DVD
CD-DA
V-CD
IC
L
L
H
H
IC101"40"
XDVD
L
L
H
L
IC101"41"
XCD2
L
L
H
H
IC101"42"
XCD4
L
H
H
H
CN101"7"
SRF1
* Mechanical unit is defective
(4) Focus ON NG
* Is FE output? (TP101) Pattern, IC101
* Is control signal sent? (W002) Pattern, IC301
* Is driving voltage sent?
CN101"20", "21" If NG, pattern, driver, mechanical unit (with the power turned off, measure the
resistance between CN101"20" and "21").
* Are IC101"40" to "42", CN101"7" (SRF1) as below? (Changes with disc type.)
Mechanical unit (laser power too low), IC101 (defective gain)
If checking a) or b) resulted in NG, IC301 may be defective.
50msec
Approx.
500mV
GND
2.5V