JBL PowerBass PB12, Service Manual

Page: 19 / 43

PB12
19
Integrated Circuit Diagrams
U1,U2 (LM324, TLO64))
2
Base
3 Collector
1 Emitter
1
2
3
Q10,Q11 (MPSA56)
2
Base
3 Collector
1 Emitter
1
2
3
Q12 (2N4401)
0
0
2
2
7
D
S
G
N-Chan JFET
Q1 2N5457
+6V 15
16
17
V+
1 +6V
2
V+
3
18
4
O/P
19 5
O/P
20
6
V- V-
21 7
22
8
SD 24
+15V 23 9 +15V
10 SD
FR 25 11 FR
I/P 26 12 I/P
GND 27 13 GND
-15V 28 14 -15V
00228
NOTE: THE FOLLOWING PROCEDURES MUST BE
FOLLOWED WHEN INSTALLING NEW S53AMI/S64AMI
AMP MODULES:
FAILURE TO FOLLOW ONE OR MORE OF THESE STEPS
MAY RESULT IN THE INSTANT DESTRUCTION OF THE
MODULE WHEN POWERED UP.
1. Align white indent marker on Amp Module with indent
marker on main PCB; alternately observe position of label
on top of the module; incorrectly replacing the Module
180° in the PCB slot will result in its destruction.
2. All AC powered test instruments (meters, oscilloscopes,
etc.) must have a floating ground, i.e., be connected to an
isolation transformer.
3. Align and position the Amp Module before soldering.
4. Attach the amp Module with the mounting screws before
soldering or powering up.
5. Use only rosin-core or non-acid core solder; thoroughly
de-flux the surfaces after soldering.
If the new S53AMI/S64AMI Amp Module has larger mounting
hole(s) in the case, and the stock screws no longer will fit,
and screws of the proper type cannot be obtained locally
order:
(2) part# 60301S (screws)
(2) part# 60301N (nuts)
S53AMI/S64AMI - Power Amp module SAFETY PART