(No.MB170)1-13
SECTION 4
ADJUSTMENT
4.1 Adjustment method
Tuner section
1. Tuner range
Power amplifier section
Adjustment of idling current
Attention:
This adjustment does not obtain a correct adjustment value immediately after the amplifier is used (state that an in-
ternal temperature has risen). Please adjust immediately after using the amplifier after turning off the power supply of
the amplifier and falling an internal temperature.
<Adjustment method>
(1) Set the volume control to minimum during this adjustment. (No signal & No load)
(2) Set the surround mode OFF.
(3) Turn VR787
and VR788 fully counterclockwise to warm up before adjustment.
If the heat sink is already warm from previous use the correct adjustment can not be made.
(4) For L-ch, connect a DC voltmeter between B2204
and B2205 (Lch) and, connect it between B2213 and B2214 (Rch).
(5) 30 minutes later after power on, adjust VR787 for Lch, or VR788 for Rch so that the DC voltmeter value has 1mV to 10mV.
• It is not abnormal though the idling current might not become 0mA even if it is finished to turn variable resistance (VR787
,
VR788) in the direction of counterclockwise.
FM 87.5MHz to 108.0MHz
AM 530kHz to 1710kHz
Measurement location B2204
-82205 (Lch), B2213-B2214 (Rch)
Adjustment part VR787
(Lch), VR788 (Rch)
Front amp. board (L)
VR788
Front amp. board (R)
VR787
B2204
B2205
B2213
B2214
VR787 (Lch)
B2204, B2205 (Lch)
VR788 (Rch)
B2213, B2214 (Rch)
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