Marantz 74 PM52/00B Service Manual page 19

5. IDLING CURRENT ADJUSTMENT
(1) Before switching the power ON, set the Master Volume
~ control to the minimum position and the Balance and
Tone controls to the center positions. Also set semi-fixed
resistors R719 (L CH) and R720 (L CH) on PCB P7071 to
the center positions.
(2) Each of the cement resistors R743 (L CH) and R744 (R
CH) on the PCB P701 is provided with three test points.
Connect a digital voltmeter, set for the DC voltage input,
to the test points at the two extremities of the three
test points of R743 or R744.
(3) After the setup above, 'switch the power ON and adjust
semi-fixed resistor R719 (L CH) or R720 (R CH) on
PCB P701 according to the digital voltmeter reading.
The target setting value is 14 mV (38.9 mA) for both the
L_ CH and R CH.
Please refer to the table below.
[amin amin |
Note on Safety:
Symbol A Fire or electrical shock hazard. Only original
parts should be used to replace any part marked with
Any other component substitution (other symbol A .
than original type), may increase risk of fire or electrical
shock hazard.
6. HOW TO CHANGE THE SUPPLY VOLTAGE
(A/N/T/W Versions)
With the PM-50 A and T Versions, the rated supply voltage
of 240V can he changed to 220V. In the same way, the 220V
rated supply voltage of the PM-50 N and W Versions can be
changed to 240V.
Refer to the following diagram for the voltage change pro-
cedure.
FT
r IAL 7
Ler
J953 J952
AC CORD
wool
1?)
E
' J95! io BD Zz c
Te
ae
io
€
Soldered surface of P951
After binding solder around the terminal, bundle the
brown wire and blue wire together and tighten them with
a tightener.
@ Note on Terminals J951 and J956
Wrapping terminals J951 and J956 on the P951 PC board are
critical components for the safety. Please observe the follow-
ing caution when working these terminals.
Terminal side view
Wrapping shall be performed within range A .
When binding up solder, apply solder within range B .
14 MZ 2298