Panasonic PV-DF204 Service Manual page 172

Troubleshooting Hints
How to confirm whether DVD circuit or other circuits is defective.
NOTE:
Host communication may not occur correctly between IC6001 on the Main C.B.A. and IC8001 on the DVD Main C.B.A.
when there is a problem on the DVD Main C.B.A.
(Serial Data Communication failure between IC6001 and IC8001 within 30sec. IC6001 will switch automatically to VCR.)
(Check the VCR mode and DVD mode.)
Check the voltage during the 30 seconds during which the unit remains in DVD mode.
1) Confirm DVD operation and VCR operation
1. Playback a VHS tape.
2. Playback a DVD disc.
No PB VCR only
No PB DVD only
First, confirm that the Main C.B.A. is O.K. other than DVD
Mechanism Unit and DVD Main C.B.A. by referring to
"Communication Timing Chart 1," and "Communication
Timing Chart 2."
Check points:
1. All Power Supply Voltages for DVD circuit
(TP8011 (SW_3.3V_DVD), TP8523 (SW_5V_DVD),
TP8813 (M_VM_6V), Pin3 of P8402 (ACT_VM_5V)
on the DVD Main C.B.A.)
2. Output Signal from DVD Main C.B.A.(TP8009 (D_RDY)),
Output Signal from Main C.B.A.(TP8005 (H_RDY))
(TP8009 (D_RDY), TP8005 (H_RDY) on the DVD Main C.B.A.)
OK
DVD circuit is defective.
Perform troubleshooting referring to "How to confirm whether DVD Mechanism Unit or DVD Main C.B.A. is defective."
How to confirm whether DVD Mechanism Unit or DVD Main C.B.A. is defective.
Confirm communication between DVD Main C.B.A.
and Main C.B.A. by referring to "Communication Timing
Chart 2."
Check points:
1. Output Signal from DVD Main C.B.A.
(TP8006 (DVD_SCK) on the DVD Main C.B.A.)
OK
Confirm that the OPEN/CLOSE TRAY works correctly.
12
OK
Playback the test DVD disc.
The Message "PLEASE CHECK THE DISC, AND
FOR STAINS OR SCRATCHES ON DISC" appears.
DVD Mechanism Unit or IC8801 or IC8001 is defective.
Repair it referring to "Spindle Motor Operation Problem,"
and " Traverse Operation Problem," "Cause: Pickup
Problem."
Both NG Main C.B.A. is defective.
Repair the Main C.B.A.
Main C.B.A. is defective.
Repair the Main C.B.A.
NG Main C.B.A. is defective.
Repair the Main C.B.A.
NG DVD Main C.B.A. is defective.
Repair the DVD Main C.B.A.
IC8001 or the circuit around it is defective.
NG DVD Mechanism Unit or IC8801 is defective.
Repair it by referring to the "Tray Operation Problem. "
If there is problem with audio
or picture, even though it plays
back.
DVD Main C.B.A. is defective.
Repair DVD Main C.B.A.
Communication Timing Chart 1
300 ms
Pin 48 of IC6001 on the Main C.B.A.
(DVD_POWER_ON(H))
TP8010 on the DVD Main C.B.A.
(DVD_RESET(L))
Communication Timing Chart 2
DVD SERIAL START
TP8005 on the DVD Main C.B.A.
(H_RDY (VCR DVD)
TP8009 on the DVD Main C.B.A.
(D_RDY (DVD VCR)
TP8006 on the DVD Main C.B.A.
(DVD_SCK (DVD VCR)
16151413121110 9
Troubleshooting Hints of DVD Mechanism Unit
Tray Operation Problem
Check the signal at TP8954 on the DVD Sub C.B.A.
(3.0 Vp-p)
NG
Check the signal at TP8809 (TRYIN) on the DVD Main
C.B.A.
NG
IC8001 on the DVD Main C.B.A. is defective.
Replace IC8001 on the DVD Main C.B.A.
V1 2.3 Vp-p V1 1.0 Vp-p
1 V 10 s 1 V 10 s
TP8954 TP8809
(During Loading) (During Loading)
V1 2.3 Vp-p V1 1.0 Vp-p
10 s 10 s
1 V 1 V
1 V 10 us
TP8954 TP8809
(During Unloading) (During Unloading)
PV-DF204/PV-DF2004/PV-DF2004-K/PV-DF274/PV-DF2704/PV-DF2704-K
DVD SERIAL START
1 s
21 ms
MAX 3.2 ms
1 ms
8 7 6 5 4 3 2 1
OK DVD Mechanism Unit is defective.
Replace the DVD Mechanism Unit.
OK IC8801 on the DVD Main C.B.A. is defective.
Replace IC8801 on the DVD Main C.B.A.
TROUBLESHOOTING HINTS