JBL PowerBass PB10, Service Manual

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PB10
25
PB10 Testing Procedure (Cont.) (Revision 1 Only)
PB10 POWER MODULE TESTING FLOW CHART
CAUTION : MODULE OUTPUT IS FLOATING AND IS
NOT
PROTECTED AGAINST A SHORT
TO GROUND. ALL TEST INSTRUMENTS CONNECTED TO THE OUTPUT
MUST
BE FLOATING. ATTACH THE SCOPE PROBE TIP TO SPK - and REFERENCE
LEAD TO SPK+.
(A 10mV signal may need from the input to trigger the
Switch
turn on)
no
no
yes
yes
no
no
yes
yes
no
no
yes
yes
no
no
yes
yes
START
Check V+; V-;
+/-15V voltage
at the module
Check fuse
transformer,
CMC, rectifier,
C1 and C2
Use scope to
check switching
frequency from
the load 100KHz
+/-10% , ~1Vpp
Check input of
module wrt GND
= 0V D.C.
Power up with no
signal input
LED RED
OK
OK
OK
OK
OK
OK
OK
OK
Check C32 and
Pre-AMP
Use scope to
check O/P at
module wrt GND
80Vpp square
wave shown
Check L1, L2,
C10, C11
Check 6V at the
module wrt V-
=5.75V
Replace
Module
MODULE OK
END
Check D3,D4,
R3, Q10, Q11,
Q12 and SCP
Check
transformer,
CMC, rectifier,
C1, C2, D1,
D2, R1(A,B,C),
R2(A,B,C)
Check S/D volt-
age at the module
wrt V- =5.1V
Check D5,D6,
R6,R7(A,B,C)
Resistance check
(no load)
between V+ V-,
V+ O/P,V- O/P
and O/P to GND
is > 10K