Parasound JC 1 Amplifier - Manual (Page 14)

TROUBLESHOOTING GUIDE
11
JC 1 will not turn off when
audio signal is removed
PROBABLE CAUSE
Power cord is disconnected
REMEDY
Hum and / or buzz
through speakers
Ground loop between preamplifier
and JC 1 or at the equipment rack
Move the Ground Lift switch to its Lift position
Install nylon shoulder washers on both sides of
the panels of all equipment to insulate metal
from touching the rack
Check polarity of DC source with a voltmeter
Try connecting a 9 V battery to the 12V DC input
Make sure Auto On