Sony ICF-CD2000 Service Manual page 4

• Method-2 (In the service mode or normal operation):
Check the value of current flowing in the laser diode.
1. Remove the upper panel.
2. Connect a digital voltmeter as show in Fig. 2.
[CD ]
3. Press the u key.
4. Calculate current value by the reading of the digital voltmeter.
Reading of the digital voltmeter (V) ÷ 2.2 (Ω) = current value
(A)
(Example) Reading of the digital voltmeter of 0.082 V:
0.082 V÷2.2 Ω= 0.037 (A) = 37 mA
Current value of the specified: 16 to 18 mA
5. Check that the current value is within the following range.
• Current value of the specified
Variation by temperature: 0.4 mA/˚C
Current increases with temperature increased.
Current decreases with temperature decreased.
If the current is more than the range above, there is a trouble
in the automatic power control circuit or the laser diode is in
deterioration.
If less than the range, a trouble exists in the automatic power
control circuit or the optical pick-up.
– MAIN Board (Conductor Side) –
TP
L508
(GND)
L515
TP
14
TP
(RF)
(TE)
C565
C807
D512
C545
C806
C805
C569
13
D504
C568 +
A
C551
K
A
C494
R483 C419
R476
9
8
R477
IC404
99
16 1
FB401
Fig. 2 Digital voltmeter connecting location
+5
mA (25 ˚C)
–11
C540
+
TP
(VC)
R584
C504
Q505
C559
+
C561
C506
2C1B 1E R566
R501
R854
R568
Q502
2E
2E2B1C
R549 2B
+
C515
R558
1C
C552
R557
R591
C553
2C1B 1E
Q503
B C E
2E2B 1C
Q514
R576
Q507
R575
1-673-930-
TP
(IOP 1)
D501
A K
L501
C510
C541
TP
Q601
(IOP 0)
B C E
+
C608
R552
R553
R631
1C 2B 2E
C803
Q513
1E 1B 2C
C801
2C
1B
1E
11
(11)
– 4 –
digital voltmeter
(DC3 V range)
+
–