Crown Power Line One Service Manual

Page 2

The information furnished in this manual does not include all ofthe details ofdesign, 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: (219) 294-5571

WARNING

TO PREVENT SHOCK OR
FIRE HAZARD DO NOT
EXPOSE TO RAIN OR
MOISTURE!

')

RVW Sec.

Section 6

Section 7

Section 8

TABLE OF CONTENTS

Review

1. Introduction ................................................................... R-l
11. Warranty ............................................

111. Specifications ........................................

1V. Panel Configuration ...................................

V. Performance Graphs ............................................................ R-4
Illustrated Parts List

6.1 General Information ............................................................ 6-1
6.2 Standard and Special Parts ............................

6.3 Ordering Parts .......................................

6.4 Shipment ............................................

6.5 Terms ...............................................

6.6 Schematics/ Parts Lists/ Exploded View Drawings .................................... 6-3
Maintenance

7. 1 Introduction .................................................................... 7-1
7.2 Required Test Equipment . . .

7.3 Soldering Techniques ....... . . . . . . . . .

7.4 Basic Troubleshooting ............................................................ 7-7
7.5 Disassembly for Inspection, Service, Testing, Adjustment and Repairs .................. 7-8
7.6 Reassembly .............................................................. . . . 7-10
7.7 Electrical Checkout and Adjustment Procedures ............................. . .. 7-10
7.8 Troubleshooting Chart ..... . . . 7-13
7.9 Principles of Operation ....... . . . 7-15
7.10 Block Diagram Circuit Theory. . . . 7-16
711 Theory of Operation ....... .. .. 7-17
7.12 Voltage Conversion ............................................................. 7-20
Service Bulletins ................................................................ 8-1

Page 23

following procedure is omitted. The visual inspection can
be performed in 10 to IS minutes. It is recommended both
as a preventive maintenance procedure and also for its
value in determining cause of malfunction.
1) Check that all external screws are tight and that
none are missing.
2) Check all fuses/circuit breakers.
3) Check for smooth and proper operation of
switches, etc.
4) Inspect line cord for possible damage to cap, jacket
and conductors.
5) Remove protective covers as outlined in
disassembly instruction (Section 7.5).
6) Check that all attaching parts for internal circuits
are tight and that none are missing.
7) Inspect all wiring for charred insulation. or
discoloration as evidence of previous overheating
8) Check that all electrical connections are secure.
This includes wire terminals. screw and stud type
terminals, and all soldered connections.
9) Check for obvious destruction of internal structural
parts. Distortion in any ofthese parts could mean that
the unit has been dropped or subjected to severe shock.

7.5 Disassembly for Inspection,
Service, Testing, Adjustment and Repair

The extent ofdisassembly required will depend upon the
extent of inspection, service, testing, adjustment and
repair to be performed. Illustrations referred to in
parenthesis are located in the parts list (Section 6) of this
manual.

A. Cover Removal

A fairly complete visual inspection can be performed by
removing' the top (92) and bottom (93) covers.
To remove these parts, proceed as follows:
1. Remove the eleven phillips head mounting screws
(94) that secure the top cover. Gently lift cover
and remove.
2. Remove the eleven phillips head mounting screws
(94) that secure the bottom cover. As with the top
cover. the bottom cover can now easily be removed.

B. Main Board Removal

The PL-l has been specially designed for ease of service.
Every component part is easily accessible (with the covers
removed) for fast and effective replacement. This means
it should never be necessary to replace the Main Board
unless damage was done beyond repair (severed. burnt,
etc.) to the board itself. (Most cases of main board
destruction will also require output transistor
replacement as well as drivers.) If this occurs, proceed as
follows:

1. Refer to the component board layout, Fig. 6.3.

2. Disconnect all cables and wires which connect
to/from the board at solder ponts (P-l", etc.)
indicated on board layout Fig. 6.3. Note their loca-
tion for future reconnection.

3. Disconnect all wires attached to the Power and
Monitor pushbutton terminal strips. Note their loca-
tion for future reconnection.

4. Remove front panel knobs (4l) and associated
hardware. Also remove headphone jack mounting
knurled nut(6l).

5. Remove the four (two each side) phillips head
handle mounting screws (48). This will free the
black handles, black front panel, power LED, and
will also expose the aluminum frame.

6. The LED display cover (60) should be removed
next by simply lifting it out of its mounting space.
7. To remove the aluminum front panel with the
main board still attached, it will be necessary to remove
the predriver mounting hardware (62.63) from the
back (rear) side of the main board. It will then be
necessary to raise each predriver transistor to its
upright position in order to ease removal,

8. Unsolder each output transistor mounting
terminal (72) from the foil side of the Main Board.
9. Aluminum front panel and Main Board should
now be free to come forward and out. Replace the
Main board by removing two Monitor pushbutton
mounting screws (55,56) and disconnecting the display
board wire connections. Note theirlocation forfuture
hook-up.

IO. Reassembly is the reverse of above.

C. Display Board Removal

1. Refer to the component board layout (Fig. 6.3)
and note all wires which connect to the Display Board.
2. Unsolder the six Display~board connect wires at
the Main Board.

3. Remove the four phillips head, board mount
screws (53) located at each corner of the Display
Board.

4. Slide the board upward and out to remove.

5. Replacement is reverse of above.

D. Front Panel Parts Replacement

All component parts located near or on the front panel
can be replaced by removing all related mounting
hardware and unsoldering the part from the foil side of
the Main Board.

In order to change anycomponent parts from the Display
Board, it will be necessary to remove the board from the
front panel (see Display Board removal).
I. Input Level Control removal is accomplished by
first removing the front panel knobs(4l). Simply
pull straight out with fingers placed firmly around
the outside of the knob. Next, remove mounting nut
and ring washer (42,43) from the front panel. The

crown

only remaining restraint is the terminal mounting
strips which must be unsoldered from beneath. After
this point, the potentiometer can be lifted out easily.
2. On/Off switch replacement: To replace the front
panel on/ off switch (59) unsolder all related wiring
at the switch. With a small offset or S shapedscrew~
driver remove two mounting screws (Fig. 7.17). Switch
may now be replaced.

Fig. 7.17 Offset Screwdriver

3. Headphone jack replacement is done by removing
the front panel knurled nut (61) and all related wiring
at the jack itself.

4. Monitor Switch removal is accomplished in
basically the same manner as on/ off switch removal.
However, in this case it will be necessary to unsolder
the bottom mount terminal strip as well as removing
the small phillips head mounting screws (56).

5. LED On-0ft" Indicator Replacement: This
procedure is not likely to be necessary because of the
high reliability factor of the indicator LED used.
However, should an occasion arise for such a proce-
dure, remove the front panel (45) by extracting
the four phillips head handle mounting screws (48),
and removing the input level control and headphone
jack hardware. Disconnect the wire connected to the
rear of the LED by gently pulling the connecters
away from the front panel. With the handle-end"of
21 % nut driver, apply pressure to the LED from the
front panel side (Fig.7. 18). It may be necessary to gently

Fig. 7.18 LED Removal

strike the socket-end of the nut driver with a small ball
peen hammer. To replace, apply one drop of Eastmon
9 l0 cyanacrolete or Loctite Super Bonder to the edge of
the substitute LED (Fig.7. l9)during reinsertion. Apply
a small amount of pressure from the back side until the
glue has set (about IO seconds). Note: Be careful
not to use excessive amount ofglue. Reconnect supply
wires making sure polarity is correct. If in doubt.
observe the small flat edge, located to one side of the
lead-in wires on the LED (Fig. 7.20). The flat side is
the cathode or the solid orange wireside.

Fig. 7.19 Cyanacrolete Application

Fig. 7.20 Cathode Lead of LED

Page 25

7-12

(IOO MICROVOLY SCALE)

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(LEVEL OONTIIDLS' MIMMUM) EITHER
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CHANNEL
Fig. 7.22 [M Distortion Test Set-up
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7.8

Troubleshooting Chart
Symptom

High 1M Distortion Load Related

to loads)

Low dB 1M Distortion

High lM Distortion, Not Load Related
(occurs regardless of load connection)

High Signal to Noise

Protection Circuit Problem
-No current limiting

-Excessive limiting
-Current limiting

oscillation

Clipping (positive) Single Channel

Clipping (negative) Single Channel

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1.
(occurs only when amplifier is connected 2.
3.
4.

9.

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53.

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995.-

Possible Defect

Defective lC op amp (1C3A,B)

C123, C201 open

R114, R214 open or not soldered properly
C106, C206 open (amplifier will exhibit high 1M,
DC offset drift and noise)

C121, C221 open

Q113, Q213 open, leaky or shorted

Low output transistor bias
High signal to noise (see below)
C118, C118, C120, C220 open

R125, R225 value change
R161, R261 value change
C118, C218, C120, C220 value change

Loss of input ground isolation from chassis

0103, 0216 zener diode defective

Broken ground on input jack, input cable or on
input level control

Amplifier instability (oscillation - C106, C206 defective)

Current limiting transistor open
a. positive (Q105, Q205)

b. negative (Q107, Q207)

D102, 0202, 0108, D208 open
C110, C210, C107, C207 shorted
R119, R219, R111, R211 open

Q107, 0207, Q105, Q205 shorted
D108, 0208, 0102, 0202 shorted
Loose output transistor hardware

Negative feedback components in limiting transistor
circuit defective; C103. C203, C117, R217,
R106, R206, R120, C220

Open or leaky predriver; Q101, Q201

Shorted or leaky limiting transistor Q105, Q205
L101, L201 open

R113, R213 value change

Defective lC op amp (lC3A,B)

Open or leaky predriver; Q109, Q209

Shorted or leaky limiting transistor Q107, 207
L102, L202 open

R115, R215 value change

7-13

Page 30

l. Low Frequency Protect/Mute Circuitry

0n initial turn on, the PL-l will (when speakers are
connected to switched outputs) provide a seven second
delay to help eliminate annoying pops/thumps. This is
achieved through the logic circuitry of 1C2 along with
capacitors Cl and C2, resistors R6 and R7 and diodes Di
and D2. As a charge is developed across C2. a point is
reached where ICZC will go high at pin 2. This means its
output is now low (definition of hand gate; pin 1 is also
high) as it is fed into inverter lC2D. Through the inverter.
the output is once again high, activating Q] and likewise
the relay.

Note that relay Kl is normally open and therefore must
be activated in order to obtain a signal at the output.

Another feature of this circuitry is that it will also detect
any faults (excessive DC output failure, etc.) in the
amplifier system and will automatically disconnect
output to the speakers This feature monitors the IOC
circuitry as shown through connections at Q] 14 and R4.
Voltage on the collector of Ql I4 is high when the lOC
circuitry is not active. This retains the closed position of
KI and thus the output signal is not interrupted.
However, should the 10C circuit activate, Q1 14 collector
voltage will go low. At that point, lCZA will produce a
high output, allowing C3 to slowly (about 5 seconds)
build up a charge high enough to overcome the switching
threshold of lC2B. When this is achieved. the output of
lC2B will be low, producing a discrepancy at the input of
IC2C. This means the output of lC2C will be high
producing low output at inverter lC2D. turning 01 offas
well as Kl.

Fig. 7.31 Low Frequency Protect/ Mute Stage

7-20

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7.12 Voltage Conversion

Often Crown products are purchased in one country and
later moved to another requiring an AC mains
conversion. For this reason the following
chart/ explanation as well as a world-wide voltage map is
provided.

The PL-l power supply may be connected for any of five
voltages. Converting from one to another can be
accomplished with a soldering iron and a pair of wire
cutters. Follow the table shown with the schematic, and
the drawing below.

i. Remove the top cover of the PL-l (held on by 11
screws).

2. With the unit right side up, and the front panel toward
you, locate the terminal strip in the rear left-hand corner.

3. Make the appropriate change in jumpers for the
desired operating voltage. See Fig. 7.32.

4. Replace the 3 amp line fuse with a l.5 amp type 3AG
fuse, for all connections 200V and above.

5. Change the line cord tag to read the correct voltage.

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Fig. 7.32 Voltage Conversion

9