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1.
SCOPE
This document details functional test specifications for the Cobalt amp PCB assembly
396-90372.938.
1.1
Mechanical Overview
This PCB assembly is a single-paneled combination of two individual amplifier boards.
Each Cobalt powered Acoustimass Loudspeaker system is built up from one amplifier pcb
(from this panel) and one signal processing pcb (from a different panel).
1.2
Electrical Overview
The Cobalt amplifier assembly is generally similar to the AM-25P amplifier assembly. Sig-
nificant differences include:
•
the addition of one more twiddler amplifier, for a total of 5;
•
the addition of two more signal pins to the ribbon cable connector, for a total of 18 pins;
The input power requirements and the pinout of the input power connector (J702) are
backwards-compatible with AM-25P. Note that the pinout of the other two signal connec-
tors (J700 and J701) is NOT backwards compatible with AM-25P.
2.
GENERAL TEST SETUP
2.1
Power Transformer
Transformer Loewe P/N 90371.962 shall be used to power the PCB assembly. The secondary
of this transformer is equipped with a connector designed to mate with J702 on the ampli-
fier pcb.
Note this is a one-voltage transformer, so be certain to wire it appropriately for the local
line 230 voltage. Undervoltage (i.e., plugging a 240V transformer into a 120V source) will not
damage the amplifier assembly, but overvoltage (i.e., plugging a 120V transformer into a
240V source) will.
2.2
AC Mains Supply
This PCB assembly shall be tested with a main supply of 230 ± 10 Vrms, 50 Hz. The AC
main power supply must employ current limiting as detailed below. If the current limits are
exceeded, the AC input power must be disconnected immediately to protect PCB assem-
blies from catastrophic damage.
2.2.1 voltage:
2.2.2 frequency:
2.2.3 maximum inrush current:
2.2.4 maximum operating current:
audio outputs unloaded
audio outputs loaded
Framingham, MA 01701-9168
230Vrms ±10V
50Hz
7A, for the initial 80msec after power-up
150mA
1,5A
SIZE
FSCM
CLASS
A
32108
DWG NO.
TS
197297
SHEET
REV.
51
00
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