Crown PSA-2 User manual

crown
SERVICE MANUAL
PSA-2/SA2
PSA-2D /PSA-2DX/PSA-2X
SELF-ANALYZING AMPLIFIER) = xcsoo2 “1

The information furnished in this manual does not include all of the details of design, production, or variations of the
equipment. It does not cover all the possible contingencies which may arise during operation, installation, or
maintenance. Should special problems arise, or further information be desired, please contact the Crown
International Customer Services Department.
Crown International
1718 W. Mishawaka Rd.
Elkhart, Indiana 46514
Ph: [phone]
WARNING
TO PREVENT SHOCK OR
FIRE HAZARD DO NOT
EXPOSE TO RAIN OR
MOISTURE!
CROWN INTERNATIONAL, INC. 1718 W. MISHAWAKA RD. ELKHART, INDIANA 46514

RVW Sec.
™
Section 6
Section 7
Section 8
™
Review
re Introduction .
Il. Warranty ...
Ill. PSA-2 Specifications .
XI
Illustrated Parts List
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TABLE OF CONTENTS
PSA-2 Stereo Specifications
PSA-2 Monaural Specifications .
PSA-2 Balanced Input Module Specifications
SA2 Specifications .....
SA2 Stereo Specification:
SA2 Monaural Specifications .
Panel Configuration (PSA-2) .
Panel Configuration (SA2) .
PSA-2 Available Formats
Performance Graphs ...
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6.2 Standard and Special Parts ..
6.3 Ordering Parts .
6.4 Shipment ......
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6.6 Schematics/Bd. Layouts/ Parts Lists/ Exploded View Drawings ...
Maintenance
7.1 Introduction
7.2. Required Test Equipment
7.3. Soldering Techniques
7.4 Basic Troubleshooting
7.5 Discharging Instructions .
7.6 Disassembly for Inspection, Service, Testing, Adjustment and Repairs .
7.7 Reassembly
7.8 Repair Instructions.
7.9 Electrical Checkout, Troubleshooting and Adjustment .
7.10 PSA-2 HI/LO Pass Filter Frequency Alterations.
7.11 Voltage Conversion Instructions .
7.12 Block Diagram Circuit Theory
7.13 Theory of Operation
Service Bulletins ..

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LIST OF ILLUSTRATIONS
PSA-2:Front Panel .5--ciaes.csess de sao HME aes CONT Re Ml iss Sara + os oles SHES
PSA-2 Back Panel ..
SA2 Front Panel .
SA2 Back Panel ..
PSA-2 Available Formats.
Typical IM Distortion. .
Typical Output Impedance . .
Typical Frequency Response .
Output Phase Response
Typical Damping Factor (8 ohms) .
Typical Crosstalk ........
Typical Noise Spectrum. oi
Typical CMR Through Balanced Input Module
Typical Power Output
Low Frequency Protect Action
Typical Frequency Response - Balanced Input Module .
Typical AGC Action
Relay/ Power Supply Module Schematic . .
Relay Module Component Board Layout
Low Voltage Power Supply Component Board Layout .
Anti-pop Module Schematic ........
Anti-pop Module Foil Board Layout .
Anti-pop Module Component Board Layout .
Main Module #1/Output Terminal/ PNP-NPN §
Main Module #2/Output Terminal/ PNP-NPN Schematics
Main Module #1 Component Board Layout
Main Module #2 Component Board Layout
PNP Output Module Component Board Layout .
NPN Output Module Component Board Layout...
Output Terminal Module Component Board Layout .
Mother Board Module Component Board Layout .
PSA-2 Input Connector Module Schematic ..
PSA-2 Input Connector Module Component Board Layout
SA2 Input Connector Module Schematic
SA2 Input Connector Module Component Board Layout ..
PSA-2 Display Module Schematic ........
PSA-2 Display Module Foil Board Layout.
PSA-2 Display Module Component Board Layout .
SA2 Display Module Schematic ........
SA2 Display Module Foil Board Layout.
SA2 Display Module Component Board Layout .
PSA-2 B.I.M./ Filter Board Schematic
Balanced Input Module Foil Board Layout
Balanced Input Module Component Board Layout.
Filter Board Component Layout
Front Panel Assembly. .
SA2 Front Panel

Fig.
Fig.
Fig.
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Fig.
Fig.
Fig.
Fig.
Fig.
Main Chassis Assembly . .
Transformer Assembly ...
Power Capacitor Assembly .
NPN/PNP Output Assembly .
Back Panel Assembly
Final Assembly
PSA-2 Balanced Input Module Assembly .
Miniature Soldering Iron .........
Correct and Incorrect Solder Applica
Unsoldered Wire ...
External Strands ...
Cut Strands....
Wire Strippers .
Disturbed Joints . .
Cold Solder Joint.
Rosin Joint .... :
Component Lead Spacing .
Component Lead Bending .
Correct Pressure Applied ..
Acceptable Solder Joints .
Soldering to a Lug
Turret Terminal ..
Wire Braid Desoldering ..
Discharge Points ......
Component Location Diagram .
Internal Hard Wiring Diagram .
Consumable Materials Chart ...
Correct Output Waveform ............-
Correct Square Wave Output Waveform.
Mono Output Waveform
IM Distortion Test Set-up ...
Signal to Noise Test Set-up
Test-tone Output Waveform .
Filter Board Schematic ......
Filter Board Component Layout.
Voltage Conversion .......
World-wide Voltage Map
PSA-2/SA2 Block Diagram
Common Output Configuration ...
PSA-2/SA2 Output Configuration .

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REVIEW SECTION
I. Introduction
This manual contains complete service information on
the Crown PSA-2/SA2/PSA-2D/PSA-2DX/ PSA-2X
amplifiers. It is designed to be used in conjunction with
the PSA-2/SA2 Instruction Manual. However, some
important information is duplicated in this Service
Manual in case the Instruction Manuals are not readily
available.
NOT THE INFORMATION IN THIS MANUAL
IS INTENDED FOR USE BY AN EXPERIENCED
TECHNICIAN ONLY!
II.
As a Crown Warranty Service Station, you should be
familiar with Crown warranty policies. Each Instruction
Manual contains basic policies as related to the customer.
However, under questionable circumstances, please
contact the Technical Service Department or Director of
Customer Service at: Crown International, Inc., 1718
W. Mishawaka Road, Elkhart, IN 46514.
Warranty
Hl.
General Protection: Protection circuitry limits the
output level to protect the output transistor stage, even in
the case of elevated temperature. Transformer
overheating results in shutdown (STANDBY) of that
particular channel. Controlled slewing rate voltage
amplifiers protect the unit against RF burnouts. Input
overload protection is furnished by a resistor at the input
of the amplifier to limit current.
PSA-2 Specifications
DC Output Offset: (Shorted input) +10 millivolts.
Phase Response: +0, -15 degrees DC-20KHz at I watt.
Input Impedance: (XLR balanced) 20K ohms.
(phone jack unbalanced) 25K ohms +30%.
High Voltage Power Supply: Two 800VA transformers
with computer grade capacitors powered through 10A
relays.
Low Voltage Power Supply: +15V DC supplies are
provided by a current limited shortproof regulator.
Power Requirements: 50-60Hz AC with adjustable taps
for 100, 120, 200, 220, and 240 +10% operation. Draws 90
watts or less on idle 800W at 250W channel output into 8
ohms.
Turn On: May be switch selected for instantaneous or
four second delay after applying power. No dangerous
transients.
Low Frequency Load Protect.: May be switch selected to
produce shutdown (STANDBY) of high voltage power
supply for DC outputs greater than 26V or low frequency
outputs greater than 26V at 5Hz (see Graph RVW.15).
Controls: Two position ON/OFF rotary switch.
Ch. | and Ch, 2 input level controls.
The LOW FREQ PROTECT, DELAY and STEREO/
MONO slide switches are located on the rear panel.
Displays: A yellow LED indicates STANDBY mode
activated for that respective channel.
A pair of green LED's indicate SIGNAL presence at the
output of that respective channel.
A pair of red LED's (IOC) indicate amplifier
OVERLOAD conditions for that respective channel.
An amber LED POWER indicator driven by low power
control supply.
Connectors: Unbalanced Input - 4” phone jacks.
Output-color coded dual binding posts on standard %4”
centers; spaced %” apart for mono (balanced) output
connection.
AC Line - Three wire 20A, 120V male connector with 5 ft.
cable.
Ground Selectivity - 2 lug terminal block with removable
shorting strap.
Module Plug-ins: Standard rear-panel balanced input
module (module replacement information available
upon request).

Dimensions: 19” standard rack mount (EIA Standard
RS-310-B) 7” height, 1434” behind mounting surface.
Handles extend 2'4” in front of mounting surface. Center
of gravity is 5.4” behind the front panel.
Weight: 57 pounds (25.8Kg) net weight.
Finish: Satinized aluminum front panel with gray suede
Lexan insert and black adonized aluminum chassis and
covers.
Construction: Aluminum chassis, specially designed
“flow-through” ventalation top front and side panels.
Heavy duty handles to ease transport. Plug in rear panel
balanced input module.
Heat Sinking: Forced air with high efficiency coolers. A
two speed fan with an intake filter (washable) mounted
on the back (rear) of the amplifier forces air through
coolers and out both the top and sides of the amplifier.
IV. PSA-2 Stereo Specifications
(Exclusive of Balanced Input Module)
Output Power: 220 watts per channel minimum RMS
(both channels operating) into an 8 ohm load, 20Hz-
20KHz at a rated RMS sum total harmonic distortion of
0.05% of the fundamental output voltage (tested per
FTC specifications), 250 watts +IdB per channel,
20Hz- 20K Hz into 8 ohms with no more than 1.0% THD
(EIA Std. SE-101-A).
Output Power (4 ohms): 400 watts +1dB per channel,
20Hz-20K Hz into 4 ohms with no more than 1.0% THD
(EIA Std. SE 101-A).
Output Power (2 ohms): 685 watts +1dB at IK Hz per
channel into 2 ohms with no more than 1.0% THD.
Hum and Noise: | 15dB below rated output “A” weighted
110dB below rated output (20Hz-20K Hz).
Response: + 0.1dB 20Hz-20K Hz at | watt into 8 ohms +0 -
1,5dB DC-80K Hz.
Harmonic Distortion: Less than 0.002% from 20Hz-
1KHz and increasing linearly to 0.05% at 20K Hz at 220
watts into 8 ohms, per channel.
IM Distortion: Less than 0.01% from 0.25 watts to 220
watts into 8 ohms per channel.
Slewing Rate: Greater than 30 volts per microsecond.
Damping Factor: Greater than 700, DC to 400Hz into 8
ohms.
Output Impedance: Less than 12 milliohms in series with
less than 1,2 microhenries.
Load Impedance: Rated for 16, 8, and 4 ohm usage, safe
with all loads.
Voltage Gain: 20+2% or 26dB +.2dB at maximum gain.
Input Sensitivity: 2.1 volts for 220 watts into 8 ohms.
Output Signal: Unbalanced, dual channel.
V. PSA-2 Monaural Specifications
(Exclusive of Balanced Input Module)
Output Power (8 ohms): 800 watts + 1dB; 20Hz-20K Hz
into 8 ohms with no more than 1.0% THD (EIA std.
SEIOI-A).
Output Power (16 ohms): 500 watts + 1dB; 20Hz-20K Hz
into 16 ohms with no more than 1.0% THD (EIA Std.
SE-101-A).
Output Power (4 ohms): 1370 watts +1dBat IK Hzinto4
ohms with no more than 1.0% THD.
Frequency Response: +0.2dB, DC-20K Hz at | watt into
16 ohms.
Harmonic Distortion: Less than 0.003% from 20Hz to
IKHz and increasing linearly to 0.08% at 20KHz, 500
watts into 16 ohms.
Less than 0.005% from 20Hz to 1KHz and increasingly
linearly to 0.12% at 20K Hz, 800 watts into 8 ohms.
IM Distortion: Less than 0.015% from 0.25 watts to 500
watts into 16 ohms.
Less than 0.015% from 0.25 watts to 700 watts into 8
ohms.
Slewing Rate: Gre
: than 60 volts per microsecond,
Damping Factor: Greater than 700, DC-400Hz into 16
ohms.
Output Impedance: Less than 24 milliohms in series with
less than 2.4 microhenries.
Load Impedance: Rated for 16 and 8 ohm usage, safe
with all loads.
Voltage Gain: 40 +2 or 32dB+.2dB at maximum gain,
Input Sensitivity: 2.2 volts for 500 watts into 16 ohms.
Output Signal: Balanced, single channel. Channel |
controls are active; Channel 2 inactive but not removed
from operation.
VI. PSA-2 Balanced Input Module
Specifications
Controls: Channel | and Channel 2 input gain adjust
with the AGC Threshold, is accessible from the rear on
the Balanced Input Module.
Hum and Noise: -85dBm equivalent input noise 20Hz-
20K Hz, 600 ohm source, gain set at unity.

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Frequency Response: Flat +0.2dB 20Hz to 20KHz.
High and Low Pass Filters: 3 pole Butterworth
18dB/octave; SOHz and 1S5KHz standard frequencies.
(Other roll-off points available; see Sec. 7.10 for details.)
Slide switch activated.
Compressor Action: Range of compression restricted to
13d B by design (wider range would aggravate feedback in
live performance). Threshold adjustable from overload
level of main amplifier to 12dB lower.
Balanced Input Voltage Gain: Variable 0-10 +30%.
Test Tone: Switch activated wide spectrum 50Hz-20K Hz
tone.
Common Mode Rejection: 70dB 5SHZ-3KHz
55dB 20K Hz (see Graph RVW.13).
VII. SA2 Specifications
General Protection: Protection circuitry limits the
output level to protect the output transistor stage, even in
the case of elevated temperature. Transformer
overheating results in shutdown (STANDBY) of that
particular channel. Controlled slewing rate voltage
amplifiers protect the unit against RF burnouts. Input
overload protection is furnished by a resistor at the input
of the amplifier to limit current.
DC Output Offset: (Shorted input) +10 millivolts.
Hum and Noise: | 15dB below rated output “A” weighted
110dB below rated output (20Hz-20K Hz).
Phase Response: +0, -15 degrees DC-20KHz at | watt.
Input Impedance: 25K ohms +30%.
High Voltage Power Supply: Two 800VA tranformers
with computer grade capacitors powered through 10A
relays.
Low Voltage Power Supply: +15V DC supplies are
provided by a current limited shortproof regulator.
Power Requirements: 50-60Hz AC with adjustable taps
for 100, 120, 200, 220, and 240+ 10% operation. Draws 90
watts or less on idle; 800W at 220W channel into 8 ohms.
Turn On: May be switch selected for instantaneous or
four second delay after applying power. No dangerous
transients.
Low Fregency Load Protect: May be switch selected to
produce shutdown (STANDBY) of high voltage power
supply for DC outputs greater than 26V or low frequency
outputs greater than 26V peak at S5Hz into 8 ohms.
Controls: Two position ON/OFF rotary switch. Right
and Left Input Level controls. The LOW FREQ
PROTECT, DELAY and STEREO/MONO slide
switches are located on the rear panel.
Displays: An amber LED indicates power on. A pair of
yellow LED's indicate STANDBY mode activated for
that respective channel. Two sets of fifteen green LED's
form a display ladder that indicate by peak-hold and
running peak simultaneously, the amplifier’s output level
over a 42dB range. A pair of red LED's, 1OC (Input
Output Comparator), indicate amplifier overload for
that respective channel.
Connectors: Unbalanced Input - pin jacks. OutputColor
coded dual binding posts on standard 4%” centers; spaced
¥,” apart for MONO (Balanced) output connection. AC
Line - Three wire 20A, 120V male connector with 5 ft.
cable. Ground Selectivity - 2 lug terminal block with
removable shorting strap.
Dimensions: 19” standard rack mount (EIA Standard
RS-310B) 7” height, 144” behind mounting surface.
Center of gravity is 5.4” behind front panel. Extends 2/4”
in front of mounting surface with optional handles.
Construction: Aluminum chassis, specially designed
“flow-through” ventilation top and side panels.
Heat Sinking: Forced air with high efficiency coolers. A
two speed fan with an intake filter (washable) mounted
on the rear of the amplifier forces air thru coolers and out
both the top and sides of the amplifier.
Weight: 57 pounds (25.8Kg) new weight.
Finish: Satinized aluminum front panel with gray suede
Lexan insert and black anodized aluminum chassis and
covers.
Vill.
Output Power: 220 watts per channel minimum RMS
(both channels operating) into an 8 ohm load, 20Hz-
20K Hz ata rated RMS sum total harmonic distortion of
0.5% of the fundamental output voltage.
350 watts per channel minimum RMS (both channels
SA2 Stereo Specifications
R-3
|

operating)
into
a
4
ohm
load,
20Hz-20KHz
at
a
rated
RMS
sum
total
harmonic
distortion
of
0.08%
of
the
fundamental
output
voltage.
600
watts
per
channel
minimum
RMS
(both
channels
operating)
into
a
2
ohm
load,
at
IK
Hz;
rated
RMS
sum
total
harmonic
distortion
of
1.0%
of
the
fundamental
output
voltage.
Frequency Response: +0. |dB 20Hz-20K Hzat | watt into
8 ohms +0 -1.5dB DC-80K Hz.
Harmonic
Distortion:
Less
than
0.002%
from
20Hz-
1KHz
and
increasing
linearly
to
0.05%
at
20K
Hz,
220
watts
into
8
ohms,
per
channel.
IM Distortion: Less than 0.01% from 0.25 watts to 220
watts into 8 ohms per channel.
Slewing Rate: Greater than 30 volts per microsecond.
Damping
Factor:
Greater
than
700,
DC-400Hz
into
8
ohms.
Output
Impedance:
Less
than
12
milliohms
in
series
with
less
than
1.2
microhenries.
Load Impedance: Rated for 16, 8, and 4 ohm usage, safe
with all loads.
Voltage Gain: 20 +2% or 26dB +.2dB at maximum gain.
Input Sensitivity: 2.1 volts for 220 watts into 8 ohms.
Output Signal: Unbalanced, dual channel.
IX. SA2 Monaural Specifications
Output Power: 700 watts minimum RMS into an 8 ohm
load, 20Hz-20K Hz at a rated RMS sum total harmonic
distortion of 0.12% of the fundamental output voltage.
440 watts minimum RMS into a 16 ohm load, 20Hz-
20K Hz at a rated RMS sum total harmonic distortion of
0.08% of the fundamental output voltage.
1200 watts at 1K Hz into a4 ohm load, ata rated sum total
harmonic distortion of 1.0% of the fundamental output
voltage.
Frequency Response: +0.2dB, DC-20K Hz at | watt into
16 ohms.
Harmonic Distortion: Less than 0.003% from 20H7z to
IK Hz and increasing linearly to 0.08% at 20K Hz, 440
watts into 16 ohms.
Less
than
0.005%
from
20Hz
to
IKHz
and
increasingly
linearly
to
0.12%
at
20K
Hz,
700
watts
into
8
ohms.
IM Distortion: Less than 0.015% from 0.25 watts to 440
watts into 16 ohms.
Less than 0.015% from 0.25 watts to 700 watts into 8
ohms.
Slewing Rate: Greater than 60 volts per microsecond.
Damping Factor: Greater than 700, DC-400Hz into 16
ohms.
Output
Impedance:
Less
than
24
milliohms
in
series
with
less
than
2.4
microhenries.
Load Impedance: Rated for 16 and 8 ohm usage.
Voltage Gain: 40+ 2% or 32dB +.2dB at maximum gain.
Input Sensitivity: 2.1 volts for 440 watts into 16 ohms.
Output
Signal:
Balanced,
single
channel.
Channel
1
controls
are
active;
Channel
2
inactive
but
not
removed
from
operation.

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X. Panel Configuration
10C INDICATORS
SIGNAL PRESENCE INDICATORS
INPUT LEVEL CONTROLS
STANDBY INDICATORS
ON/OFF INDICATOR
POWER CONTROL
A 8
a |
| |
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Fig. RVW.1 PSA-2 Front Panel
SG 4 a kL
© Psn-2
SeiF ANAWZING
‘ampuricr
Pp Q eR
BALANCED INPUT MODULE
OUTPUT BANANA JACKS
LOW PASS FILTER SWITCHES
GAIN ADJUST CONTROLS
HIGH PASS FILTER SWITCHES
TEST TONE GENERATOR SWITCH
BALANCED XLR INPUT JACKS
FAN FILTER COVER
GROUND TERMINAL STRIP
DELAY SWITCH
LOW FREQ. PROTECT SWITCH
STEREO/MONO SWITCH
UNBALANCED INPUT JACKS
AGC THRESHOLD CONTROL
a9 7zoRxozZ0|
Erxe-z09
Fig. RVW.2 PSA-2 Back Panel