JVC RX-D Series Training Book page 64

•Before power on, check any short between pins of drive IC
pins.
•Without the pair of MOSFET in circuit, the OC (over current ) at
pin 5 of IC does not function.
•There are 7 drive ICs- IRS20124S-X- for driving the 7 pair of
MOSFETs at the audio output channels.
•The 'AMP +/-B' voltage varies from +/- 25 to 40V depending on
the models, and output level.
•Since the 'AMP +/-B' voltage varies, it is recommended to use
'AMP –B' as reference common point to measure DC level at
IC251. When referred to chassis ground, the voltage readings
will be different from the listed values.
•Since the voltage at pin 10, 11 and 12 are floating, the DC level
varies along with 'AMP_ +/-B'.