JVC A-K100 - Block Diagram

A-K100 |
4. Block Diagram
PHONO
DAD/ AUX
TUNER
1c 30!
MAIN AMP
TONE CONTROL
: 172 NJM 45580-D
SOURCE
Q701~@716
BALANCE VOLUME LOUDNESS
sw
SPEAKER
5. Power Amplifier Idling Current Adjustment Procedures
Adjustment Location on ENH-031-1 Main Amp. P.C. Board Ass’y
1-5
(No. 2736)
1. Before turing on the power, turn the semi-fixed resis-
tors < R727 for L channel and R728 for R channel >
of the power amplifier circuit board fully counterclock-
wise.
. Adjust the semi-fixed resistors (R727) and (R728) so
that the voltage at the following test points of the
power amplifier circuit board is within a range of 1 mV
~ 3 mV after the power is turned on.
L channel: Measure the voltage between test point
(emitter of Q713 and output at the test
point @).
R channel: Measure the voitage between test point ©)
(emitter of Q714 and output at the test
point ()).
. Readjust resistors R727 and R728 about 5 minutes
after the power is turned on (the heatsink temperature
must be sufficiently high) so that the voltage at the test
points becomes 10 mV.
Confirm that the voltage does not vary when the heat-
sink temperature increases further.