Crown PB-1, Power Base 1 Service manual

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Page 1

Power Base-1 & 460CSL Amplifier Service Manual

POWER AMPLIFIER

SERVICE MANUAL

POWER BASE-1® & 460CSL

Mailing Address:

P.O. Box 1000

Elkhart, IN U.S.A. 46515-1000

Shipping Address:

57620 C.R. 105

Elkhart, IN U.S.A. 46517

™

CSL™ is a trademark and Power Base-1,® ODEP® and Crown® are registered trademarks of Crown International, Inc.

K-SVCPB1

1-95

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Power Base-1 & 460CSL Amplifier Service Manual

Table of Contents

Introduction .............................................................4

Scope......................................................................4

Warranty..................................................................4

Parts ........................................................................ 5

Specifications..........................................................6

Voltage Conversion ................................................. 7

Circuit Theory .......................................................... 8

Test Procedures.................................................... 13

Mechanical Parts Listing .......................................17

Module Information ...............................................20

Q42576-1 Output Module (Original) .....................21

Q42661-1 Output Module (#2) .............................. 22

Q42718-9 Output Module (#3) .............................. 23

Q42885-6 Output Module (TO-3P)........................24

Q42967-2 Output Module (THC)...........................25

Q43200-7 Output Module (THC #2)......................26

Q42552A0 Main Module (Original)........................27

Q42664-5 Main Module (Service Only) ................. 29

Q42682-7 Main Module (#2) .................................31

Q42776-7 Main Module (3rd Gain) ....................... 34

Q42953-2 Main Module (3rd Gain PB-1) .............. 37

Q43060-5 Main Module (THC) ..............................40

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Power Base-1 & 460CSL Amplifier Service Manual

Specifications

Unless noted otherwise, all specifications are based on driving an 8 ohm load per channel, both channels driven, the sensitivity switch in the 26dB position, the AC supply is 120VAC at 60Hz. Crown specifications are guaranteed through the warranty period (normally 3 years). Because our testing methods are more stringent than our published specifications, every Crown amplifier will exceed its published specifications.

POWER

Power

8 Ohm Stereo—205W/Ch 4 Ohm Stereo—230W/Ch 8 Ohm Bridge Mono—430W 4 Ohm Parallel Mono—425W

Load Impedances: Rated for 16, 8, 4, and 2 (parallel mono only) Ohm operation; safe with all types of loads, even totally reactive loads.

AC Mains: 120VAC at 60 Hz with standard 3 wire grounded 15A connector with single voltage transformer and fan for North American units; 100VAC, 120VAC, 220VAC, and 240VAC at 50 or 60 Hz when equipped with universal transformer, applicable fan, and other applicable hardware with country specific power cord. Note that at 50 Hz fan speed is reduced.

PERFORMANCE

Frequency Response: ±0.1dB from 20 Hz to 20 kHz at 1

Watt.

Phase Response: ±10° from 10 Hz to 20 kHz at 1 Watt. Signal to Noise Ratio: Better than 105 dB (A-weighted)

below max. average power from 20 Hz to 20 kHz. Total Harmonic Distortion (THD): <0.05% from 20 Hz to

1 kHz, increasing linearly to 0.1% at 20 kHz at 170W. I.M. Distortion: <0.05% from 10 milliwatts to 170W at 26

dB gain.

Slew Rate: >13V per microsecond. Damping Factor: >1000 from 10 Hz to 400 Hz.

Input Impedance: Nominally 20K ohms balanced; 10K

ohms unbalanced. Output Impedance: <10 milliohms in series with <2

microhenries. Protection Systems: Output Device Emulation Protec-

tion (ODEP) limits drive in the event of dangerous dynamic thermal conditions without interrupting power. Current limiting for shorted load protection. DC/LF and common mode output current Fault circuitry to mute audio. Delay of 4 seconds from turn on mutes amplifier to prevent dangerous turn-on transients. High voltage fuse in main transformer primary and low voltage fuse in fan primary. Slew rate limiting to prevent RF burn out.

MECHANICAL

Input Connectors: Balanced 1/4 inch phone jacks. Output Connectors: Color-coded 5-way binding posts

on 3/4 inch centers; spaced 3/4 inch apart.

Front Panel Controls: A rocker on/off power switch. Back Panel Controls: A three-position switch which

selects Stereo, Bridge-Mono, or Parallel-Mono mode; a two position input ground-lift switch, and level controls for each channel.

Internal Controls: A three-position switch selects 0.775V,

1.4V, or 26 dB voltage gain input sensitivity (all units manufactured with D 7911-7 main module or later; earlier models only allowed for 0.775V or 26 dB gain).

Indicators: Red Enable indicator shows on/off status of low-voltage power supply.

Construction: Black splatter-coat steel chassis with specially designed flow-through ventilation system.

Mounting: Standard EIA 310 front-panel rack mount with supports for supplemental rear corner mounting.

Dimensions: 19 inches wide, 3.5 inches high, 16 inches deep behind front mounting surface.

DC Offset: <10 millivolts.

Weight: 30 lbs.

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Power Base-1 & 460CSL Amplifier Service Manual

Voltage Conversion

PB/CSL Universal Fuse Board

BLU

BRN

P19

P20

P10

P16

P15

P14

P13

P12

P11

P22

100V Connections: P10 to P15 P11 to P14 P7 to P12

120V Connections: P10 to P16 P11 to P14 P7 to P13

220V Connections: P10 to P15 P9 to P14 P8 to P13

240V Connections: P10 to P16 P9 to P14 P8 to P13

For list of applicable transformer, fuse F100, fanformer, and power cord refer to voltageparts cross-reference.

F1F100

P18

S1 Power Switch

P17

Note: The only versions of this product produced at the Crown Factory with international voltage capabilities built in are CSL versions built specifically for sale outside the United States.

P21

Specific parts are required for the PB-1/460CSL in order to be used at different international line voltages. Refer also to Mechanical Parts Lists.

100V AC Mains: 10A Fuse A10285-26

0.5A Low Voltage Supply Fuse A10285-7 Power Transformer (Universal) D 7598-2 Transmotor 120V 50 Hz H43055-5

120V AC Mains: 10A Fuse A10285-26

0.5A Low Voltage Supply Fuse A10285-7 Power Transformer (Universal) D 7598-2 Power Transformer (United States) D 6589-2 Transmotor 120V 50 Hz H43055-5 Transmotor 120V 60 Hz H43065-4

220V to 240V AC Mains: 5A Fuse A10285-21

0.5A Low Voltage Supply Fuse A10285-7 Power Transformer D 7598-2 Transmotor 120V 50 Hz H43055-5

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Power Base-1 & 460CSL Amplifier Service Manual

Theory

OVERVIEW

It should be noted from the outset that the PB-1 and 460CSL amplifiers are electrically and mechanically identical products. The only differences, from a service perspective, are cosmetic. For the purposes of servicing the products, it should also be known that the CSL version has been on the market since 1992. Since the PB amplifiers have been in production since the mid-1980’s there are a number of electrical and mechanical parts associated with the older PB models only. It is also important to realize that over time Crown has introduced numerous improvements to PB/CSL amplifiers. Though often changes are minor, and are made for a variety of reasons, a few changes have had a significant impact on the operation of the circuitry. This manual is up to date as of the time of writing. For additional information regarding these amplifiers, refer to the applicable Technical Notes provided by Crown for this product.

This section of the manual explains the general operation of a typical Crown power amplifier. Topics covered include Front End, Grounded Bridge, and ODEP. Due to variations in design from vintage to vintage (and similarities with other products Crown) the theory of operation remains simplified.

FEATURES

Power Base/CSL amplifiers utilize numerous Crown innovations including grounded bridge and ODEP technologies. Cooling techniques make use of the what is essentially air conditioner technology. Air flows bottom to top, and front to side. Air flows a short distance across a wide heatsink. This type of air flow provides significantly better cooling than the “wind tunnel” technology used by many other manufacturers. Output transistors are of the metal can type rather than plastic case. This allows for a significantly higher thermal margin for the given voltage and current ratings. All devices used are tested and graded to ensure maximum reliability. Another electronic technique used is negative feedback. Almost all power amplifiers utilize negative feedback to control gain and provide stability, but Crown uses multiple nested feedback loops for maximum stability and greatly improved damping. Most Crown amplifiers have damping in excess of 1000 in the bass frequency range. This feedback, along with our compensation and ultra-low distortion output topology, make Crown amplifiers superior.

Features specific to the Power Base/CSL Series’ in-

clude a single core transformer (one primary with two independent ungrounded secondaries), a full time full speed fan which also serves as the low voltage transformer, slew rate limiting, and audio muting for delay or protective action. This amplifier can operate in either a Bridged or Parallel Mono mode as well as dual (stereo). A sensitivity switch allows selection of input voltage required for rated output. Level controls are rear mounted. The only indicator provided tells the operator that the low voltage supply is energized. In general, the packaging of this model is designed for maximum watt/price/weight/size value. It is the most basic grounded bridge amplifier now available from Crown.

For additional details refer to the specification section, or to the applicable Owner’s Manual.

FRONT END OPERATION

The front end is comprised of three stages: Balanced Gain Stage (BGS), Variable Gain Stage (VGS), and the Error Amp. Figure 1 shows a simplified diagram of a typical front end with voltage amplification stages.

Balanced Gain Stage (BGS)

Input to the amplifier is balanced. The shield may be isolated from chassis ground by an RC network to interrupt ground loops (early models did not have the Ground Lift feature) via the Ground Lift Switch. The non-inverting (hot) side of the balanced input is fed to the non-inverting input of the first op-amp stage. The inverting (negative) side of the balanced input is fed to the inverting input of the first op-amp stage. A potentiometer is provided for common mode rejection adjustment. Electrically, the BGS is at unity gain. (From an audio perspective, however, this stage actually provides +6dB gain if a fully balanced signal is placed on its input.) The BGS is a non-inverting stage. It’s output is delivered to the Variable Gain Stage.

Variable Gain Stage (VGS)

Note: Older models only had two front end stages. The functions of this stage were combined, primarily, with those of the third.

From the output of the BGS, the signal goes to the VGS where gain is determined by the position of the Sensitivity Switch, and level is determined by the level control. VGS is an inverting stage with the input being fed to its op-amp stage. Because gain after this stage is fixed at 26dB (factor of 20), greater amplifier sensi-

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Power Base-1 & 460CSL Amplifier Service Manual

Theory

tivity is achieved by controlling the ratio of feedback to input resistance. The Sensitivity Switch sets the input impedance to this stage and varies the gain such that the overall amplifier gain is 26 dB, or is adjusted appropriately for 0.775V or 1.4V input to attain rated output. Note that earlier models (before main modules built with D 7911-7 board) did not support the 1.4V sensitivity.

Error Amp

The inverted output from the VGS is fed to the noninverting input of the Error Amp op-amp stage through an AC coupling capacitor and input resistor. Amplifier output is fed back via the negative feedback (NFb) loop resistor. The ratio of feedback resistor to input resistor fixes gain from the Error Amp input to the output of the amplifier at 26 dB. Diodes prevent overdriving the Error Amp. Because the Error Amp amplifies the difference between input and output signals, any difference in the two waveforms will produce a near open loop gain condition which in turn results in high peak output voltage. The output of the Error Amp, called the Error Signal (ES) drives the Voltage Translators.

VOLTAGE AMPLIFICATION

The Voltage Translator stage separates the output of the Error Amp into balanced positive and negative drive voltages for the Last Voltage Amplifiers (LVAs), translating the signal from ground referenced ±15V to ±Vcc reference. LVAs provide the main voltage amplification and drive the High Side output stages. Gain from Voltage Translator input to amplifier output is a factor of 25.2.

Voltage Translators

A voltage divider network splits the Error Signal (ES) into positive and negative drive signals for the balanced voltage translator stage. These offset reference voltages drive the input to the Voltage Translator transistors. A nested NFb loop from the output of the amplifier mixes with the inverted signal riding on the offset references. This negative feedback fixes gain at the offset reference points (and the output of the Error Amp) at a factor of -25.2 with respect to the amplifier output. The Voltage Translators are arranged in a common base configuration for non-inverting voltage gain with equal gain. They shift the audio from the ±15V reference to VCC reference. Their outputs drive their respective LVA.

Also tied into the Voltage Translator inputs are ODEP limiting transistors and control/protection transistors. The ODEP transistors steal drive as dictated by the ODEP circuitry (discussed later). The control/protection transistors act as switches to totally shunt audio to ground during the turn-on delay, or during a DC/LF or Fault protective action.

Last Voltage Amplifiers (LVAs)

The Voltage Translator stage channels the signal to the Last Voltage Amplifiers (LVA's) in a balanced configuration. The +LVA and -LVA, with their push-pull effect through the Bias Servo, drive the fully complementary output stage. The LVAs are configured as common emitter amplifiers. This configuration provides sufficient voltage gain and inverts the audio. The polarity inversion is necessary to avoid an overall polarity inversion from input jack to output jack, and it

Audio

Inputs

BGS VGS Error

Amp

Figure 1. Typical Amplifier Front End and Voltage Amplification Stages.

+15V

Voltage Divider

-15V

ODEP

Q100

Q103

Mute

Q121

Q122

NFb Loop

Voltage

Translators

Q101

Q102

+VCC

Q105

NPN Outputs (+HS) PNP Outputs (-HS)

Q110

-VCC

LVA's

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Power Base-1 & 460CSL Amplifier Service Manual

Theory

allows the NFb loop to control Error Amp gain by feeding back to its non-inverting input (with its polarity opposite to the output of the VGS). With the added voltage swing provided by the LVAs, the signal then gains current amplification through the Darlington emitter-follower output stage.

GROUNDED BRIDGE TOPOLOGY

Figure 2 is a simplified example of the grounded bridge output topology. It consists of four quadrants of three deep Darlington (composite) emitter-follower stages per channel: one NPN and one PNP on the High Side of the bridge (driving the load), and one NPN and one PNP on the Low Side of the bridge (controlling the ground reference for the rails). The output stages are biased to operate class AB+B for ultra low distortion in the signal zero-crossing region and high efficiency.

High Side (HS)

The High Side (HS) of the bridge operates much like a conventional bipolar push-pull output configuration. As the input drive voltage becomes more positive, the HS NPN conducts and delivers positive voltage to the load. Eventually the NPN devices reach full conduction and +Vcc is across the load. At this time the HS PNP is biased off. When the drive signal is negative going, the HS PNP conducts to deliver -Vcc to the load and the HS NPN stage is off.

The output of the +LVA drives the base of predriver device. Together, the predriver and driver form the first two parts of the three-deep Darlington and are biased class AB. They provide output drive through the bias resistor, bypassing the output devices, at levels below about 100mW. An RLC network between the predriver and driver provide phase shift compensation and limit driver base current to safe levels. Output devices are biased class B, just below cutoff. At about 100mW output they switch on to conduct high current to the load. Together with predriver and driver, the output device provide an overall class AB+B output.

The negative half of the HS is almost identical to the positive half, except that the devices are PNP. One difference is that the PNP bias resistor is slighter greater in value so that PNP output devices run closer to the cutoff level under static (no signal) conditions. This is because PNP devices require greater drive current.

HS bias is regulated by Q18, the Bias Servo. Q18 is a Vbe multiplier which maintains approximately 3.3V Vce under static conditions. The positive and negative halves of the HS output are in parallel with this 3.3V. With a full base-emitter on voltage drop across predrivers and drivers, the balance of voltage results in approximately .35V drop across the bias resistors in

+Vcc (Positive Rail)

Input signal

HIGH SIDE LOW SIDE

Load

(speaker)

-Vcc (Negative Rail)

Inverting Op-amp

Figure 2. Crown Patented Grounded Bridge Topology

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Power Base-1 & 460CSL Amplifier Service Manual

Theory

the positive half, and about .5V across the bias resistor in the negative half. Q18 conduction (and thus bias) is adjustable.

A diode string prevents excessive charge build up within the high conduction output devices when off. Flyback diodes shunt back-EMF pulses from reactive loads to the power supply to protect output devices from dangerous reverse voltage levels. An output terminating circuit blocks RF on output lines from entering the amplifier through its output connectors.

Low Side (LS)

The Low Side (LS) operates quite differently. The power supply bridge rectifier is not ground referenced, nor is the secondary of the main transformer. In other words, the high voltage power supply floats with respect to ground, but ±Vcc remain constant with respect to each other. This allows the power supply to deliver +Vcc and -Vcc from the same bridge rectifier and filter as a total difference in potential, regardless of their voltages with respect to ground. The LS uses inverted feedback from the HS output to control the ground reference for the rails (±Vcc). Both LS quadrants are arranged in a three-deep Darlington and are biased AB+B in the same manner as the HS.

When the amplifier output swings positive, the audio is fed to an op-amp stage where it is inverted. This inverted signal is delivered directly to the bases of the positive (NPN) and negative (PNP) LS predrivers. The negative drive forces the LS PNP devices on (NPN off). As the PNP devices conduct, Vce of the PNP Darlington drops. With LS device emitters tied to ground, -Vcc is pulled toward ground reference. Since the power supply is not ground referenced (and the total voltage from +Vcc to -Vcc is constant) +Vcc is forced higher above ground potential. This continues until, at the positive amplifier output peak, -Vcc = 0V and +Vcc equals the total power supply potential with a positive polarity. If, for example, the power supply produced a total of 70V from rail to rail (±35VDC measured from ground with no signal), the amplifier output would reach a positive peak of +70V.

Conversely, during a negative swing of the HS output where HS PNP devices conduct, the op-amp would output a positive voltage forcing LS NPN devices to conduct. This would result in +Vcc swinging toward ground potential and -Vcc further from ground potential. At the negative amplifier output peak, +Vcc = 0V and -Vcc equals the total power supply potential with

a negative polarity. Using the same example as above, a 70V supply would allow a negative output peak of 70V. In summary, a power supply which produces a total of 70VDC rail to rail (or ±35VDC statically) is capable of producing 140V peak-to-peak at the amplifier output when the grounded bridge topology is used. The voltage used in this example are relatively close to the voltages of the PB-1/460CSL.

The total effect is to deliver a peak to peak voltage to the speaker load which is twice the voltage produced by the power supply. Benefits include full utilization of the power supply (it conducts current during both halves of the output signal; conventional designs require two power supplies per channel, one positive and one negative), and never exposing any output device to more than half of the peak to peak output voltage (which does occur in conventional designs).

Low side bias is established by a diode string which also shunts built up charges on the output devices. Bias is adjustable via potentiometer. Flyback diodes perform the same function as the HS flybacks. The output of the LS is tied directly to chassis ground via ground strap.

OUTPUT DEVICE EMULATION PROTECTION (ODEP)

To further protect the output stages, a specially developed ODEP circuit is used. It produces a complex analog output signal. This signal is proportional to the always changing safe-operating-area margin of the output transistors. The ODEP signal controls the Voltage Translator stage by removing drive that may exceed the safe-operating-area of the output stage.

ODEP senses output current by measuring the voltage dropped across LS emitter resistors. LS NPN current (negative amplifier output) and +Vcc are sensed, then multiplied to obtain a signal proportional to output power. Positive and negative ODEP voltages are adjustable via two potentiometers. Across ±ODEP are a PTC and a thermal sense (current source). The PTC is essentially a cutoff switch that causes hard ODEP limiting if heatsink temperature exceeds a safe maximum, regardless of signal level. The thermal sense causes the differential between +ODEP and – ODEP to decrease as heatsink temperature increases. An increase in positive output signal output into a load will result in –ODEP voltage dropping; an increase in negative output voltage and current will cause +ODEP voltage to drop. A complex RC network between the

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Power Base-1 & 460CSL Amplifier Service Manual

Theory

±ODEP circuitry is used to simulate the thermal barriers between the interior of the output device die (immeasurable by normal means) and the time delay from heat generation at the die until heat dissipates to the thermal sensor. The combined effects of thermal history and instantaneous dynamic power level result in an accurate simulation of the actual thermal condition of the output transistors.

BALANCED

INPUTS

+VOLTAGE

TRANSLATOR

VGSBGS

-1

ERROR

AMP

OUTPUT

DEVICE

EMULATION

PROTECTION

-VOLTAGE

TRANSLATOR

+LVA

-1

HIGH SIDE

BIAS

SERVO

-LVA

-1

MAIN NEGATIVE FEEDBACK (NFb) LOOP

LOW SIDE

-1

INVERTING

BRIDGE

BALANCE

BIAS

DIODE

STRING

POSITIVE

HIGH SIDE

OUTPUT

NPN STAGE

NEGATIVE HIGH SIDE

OUTPUT

PNP STAGE

POSITIVE

LOW SIDE

OUTPUT

NPN STAGE

NEGATIVE LOW SIDE

OUTPUT

PNP STAGE

Figure 3. Typical Crown Amplifier Basic Block Diagram (One Channel Shown)

Page 10

Power Base-1 & 460CSL Amplifier Service Manual

Checkout Procedures

GENERAL INFORMATION

The following test procedures are to be used to verify operation of this amplifier. DO NOT connect a load or inject a signal unless directed to do so by the procedure. These tests, though meant for verification and alignment of the amplifier, may also be very helpful in troubleshooting. For best results, tests should be performed in order.

All tests assume that AC power is from a regulated 120 VAC source. Test equipment includes an oscilloscope, a DMM, a signal generator, loads, and I.M.D. and T.H.D. noise test equipment.

STANDARD INITIAL CONDITIONS

Level controls fully clockwise. Stereo/Mono switch in Stereo. Sensitivity switch in 26 dB fixed gain position. It is assumed, in each step, that conditions of the amplifier are per these initial conditions unless otherwise specified.

TEST 1: DC OFFSET

Spec: 0 VDC, ±10 mV. Initial Conditions: Controls per standard, inputs shorted. Procedure: Measure DC voltage at the output connec-

tors (rear panel). There is no adjustment for output offset. If spec is not met, there is an electrical malfunction. Slightly out of spec measurement is usually due to U104/U204 out of tolorance.

The following is a list of ODEP Bias Voltages VS. Temperature. °F °C V

–ODEP

+ODEP

66 18.9 –10.31 11.41 68 20.0 –10.26 11.36 70 21.1 –10.20 11.30 72 22.2 –10.14 11.24 74 23.3 –10.09 11.19 76 24.4 –10.03 11.13 77 25.0 –10.00 11.10 78 25.6 –9.97 11.07 80 26.7 –9.91 11.01 82 27.8 –9.86 10.96 84 28.9 –9.80 10.90 86 30.0 –9.74 10.84 88 31.1 –9.69 10.79 90 32.2 –9.63 10.73 92 33.3 –9.57 10.67 94 34.4 –9.51 10.61

–ODEP Procedure: Measure pin 6 of U100 and, if necessary, adjust R121 to obtain V

as specified

–ODEP

above. Measure pin 6 of U200 and, if necessary, adjust R221 to obtain V

as specified above.

–ODEP

+ODEP Procedure: Measure pin 6 of U103 and, if necessary, adjust R132 to obtain V

as specified

+ODEP

above. Measure pin 6 of U203 and, if necessary, adjust R232 to obtain V

as specified above.

+ODEP

TEST 2: OUTPUT BIAS ADJUSTMENT

Spec: 300 to 310 mVDC. Initial Conditions: Controls per standard, heatsink tem-

perature less than 40°C. Procedure: Measure DC voltages on the output module across R31, adjust R26 if necessary. Measure DC voltages on the output module across R32, adjust R23 if necessary. Repeat for second channel.

TEST 3: ODEP VOLTAGE ADJUSTMENT

Spec: Cold Bias Per Charts Below ±0.1V DC. Initial Conditions: Controls per standard, heatsink at

room temperature 20 to 30°C (68 to 86°F). Note: This adjustment should normally be performed within 2 minutes of turn on from ambient (cold) conditions. If possible measure heatsink temperature, if not measure ambient room temperature. Use this information when referencing the chart below.

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Power Base-1 & 460CSL Amplifier Service Manual

Checkout Procedures

TEST 4: AC POWER DRAW

Spec: 90 Watts maximum quiescent. Initial Conditions: Controls per standard. Procedure: With no input signal and no load, measure

AC line wattage draw. If current draw is excessive, check for high AC line voltage or high bias voltage.

TEST 5: COMMON MODE REJECTION

Spec at 100 Hz: –70 dB. Spec at 20 kHz: –50 dB. Initial Conditions: Controls per standard. Procedure: No load. Inject a 0 dBu 100 Hz sine wave

into each channel, one channel at a time, with inverting and non-inverting inputs shorted together. At the output measure less than –44 dBu. Inject a 0 dBu 20 kHz sine wave into each channel, one channel at a time, with inverting and non-inverting inputs shorted together. At the output measure less than –24 dBu. Adjust R921 or R1021, if necessary, to obtain the required measurements. (In older units the adjustments are done using N100/N200.)

TEST 6: VOLTAGE GAIN

Spec: ±3% when the Sensitivity Switch is set for 26dB

gain, ±6% when the Sensitivity Switch is set for 0.775V or 1.4V sensitivity.

Initial Conditions: Controls per standard. Procedure: No load connected. Inject a 0.775 VAC 1

kHz sine wave with the Sensitivity Switch in the 26 dB position. Measure 15.5 VAC ±0.07 VAC at the amplifier output. Inject a 0.775 VAC 1 kHz sine wave with the Sensitivity Switch in the 0.775V position. Measure 39.9 VAC ±1.2 VAC at the amplifier output. Inject a 1.4 VAC 1 kHz sine wave with the Sensitivity Switch in the 1.4V position. Measure 39.9 VAC ±1.2 VAC at the amplifier output. Return the Sensitivity Switch to the 26 dB position.

TEST 7: PHASE RESPONSE

Spec: ±10° at 1 Watt. Initial Conditions: Controls per standard, 8 ohm load on

each channel. Procedure: Inject a 1 kHz sine wave and adjust for 1 Watt output (2.8 VAC). Check input and output signals against each other, input and output signals must be within 10° of each other.

Procedure: No Load. Inject a 1 kHz sine wave. With level controls fully clockwise you should see full gain. As controls are rotated counterclockwise, observe similar gain reduction in each channel. When complete, return level controls to fully clockwise position.

TEST 9: CURRENT LIMIT

Spec: Current Limit at 13 ±2 Amps Initial Conditions: Controls per standard. Procedure: Load each channel to 1 Ohm. Inject a 1 kHz

differentiated (or 10% duty cycle) square wave and increase output level until current limit occurs. Current limit should occur at 11 ±1 Amps. Observe clean (no oscillations) current clipping.

TEST 10: SLEW RATE & 10 KHZ SQUARE WAVE

Spec: >13V/µS. Initial Conditions: Controls per standard. Procedure: Load each channel to 8 ohms. Inject a 10

kHz square wave to obtain 40 volts peak-to-peak at each output. Observe the slope of the square wave. It should typically measure 17 to 25 V/µS. Also, the square wave must not include overshoot, ringing, or any type of oscillation.

TEST 11: CROSSTALK

Spec: <33 mVAC at 20 kHz. Initial Conditions: Controls per standard. Short input of

channel not driven. Procedure: 8 ohm load on each channel. Inject a 20 kHz sine wave into the Channel 1 input and increase output level to 37.4 VAC. Measure less than 33 mVAC at the output of Channel 2. Inject a 20 kHz sine wave into the Channel 2 input and increase output level to 37.4 VAC. Measure less than 33 mVAC at the output of Channel

TEST 12: OUTPUT POWER

Spec at 8 Ohm Stereo: 205W at 0.1% THD. Spec at 4 Ohm Stereo: 230W at 0.1% THD. Initial Conditions: Controls per standard. Procedure: Load each channel to 8 ohms. Inject a 1 kHz

sine wave and measure at least 40.5 VAC at the output of each channel. Load each channel to 4 ohms. Inject a 1 kHz sine wave and measure at least 30.3 VAC. All power measurements must be at less than 0.1% THD.

TEST 8: LEVEL CONTROLS

Spec: Level controlled by level controls. Initial Conditions: Controls per standard.

TEST 13: REACTIVE LOADS

Spec: No oscillations. Safe with all types of loads. Initial Conditions: Controls per standard.

Page 12

Power Base-1 & 460CSL Amplifier Service Manual

Checkout Procedures

Procedure Capacitive: Load each channel to 8 ohms in

parallel with 2 µF. Inject a 20 kHz sine wave with 30 VAC output for 10 seconds. Procedure Inductive: Load each channel to 8 ohms in parallel with 159 µHenries. Inject a 1 kHz sine wave with 15 VAC output for 10 seconds. Procedure Torture: Load each channel with the primary (red and black leads) of a DC-300A transformer (D 5781-6). Inject a 10 Hz sine wave at sufficient output level to cause 3 to 5 flyback pulses, for 10 seconds. Procedure Short: Inject a 60 Hz sine wave at 5 VAC. After establishing signal, short the output for 10 seconds.

TEST 14: ODEP LIMITING

Spec: No oscillation on ODEP Limiting wave form;

either channel controls limiting in Parallel Mono Mode. Initial Conditions: Controls per standard; rag or other obstruction blocking fan so that it does not turn. Procedure: Load the amplifier to 2 ohms on each channel. Inject a 60 Hz sine wave and adjust for 15 Vrms at the output. After a few minutes observe a wave form similar to Figure 4. Remove the input signal from both channels and allow the amplifier to cool for a few minutes. Switch the amplifier to Parallel Mono and remove the load from Channel 1. Inject the signal into Channel 1 and observe that ODEP limiting occurs at the output of both channels. Remove the load from Channel 2, and install the load on Channel 1. Again, observe that both channels limit. Return all amplifier controls to standard initial conditions. Remove the fan obstruction.

TEST 15: LF PROTECTION

Spec: Amplifier mutes for low frequency. Initial Conditions: Controls per standard. Procedure: No load. Inject a 0.5 Hz 6 volt peak-to-peak

square wave into each channel and verify that each channel cycles into mute.

TEST 16: SIGNAL TO NOISE RATIO

Spec: 100 dB (105 dB A-weighted) below rated 8 ohm

power.

Initial Conditions: Controls per standard. Short inputs. Procedure: Load each channel to 8 ohms. Measure

less than 400 µV at the output of each channel (or –100 dB from reference of +34.25 dBu).

TEST 17: TURN ON TRANSIENTS

Spec: No dangerous transients. Initial Conditions: Controls per standard. Procedure: From an off condition, turn on the amplifier

and monitor the output noise at the time of turn on. Note: Turn on noise may increase significantly if the amplifier is cycled off and on.

TEST 18: TURN OFF TRANSIENTS

Spec: No dangerous transients. Initial Conditions: Controls per standard. Procedure: From an on condition, turn off the amplifier

and monitor the output noise at the time of turn off. Note: Turn off noise may increase significantly if the amplifier is cycled off and on.

TEST 19: INTERMODULATION DISTORTION

Spec at 0 dB Output: 0.01%. Spec at –35 dB Output: 0.05%. Initial Conditions: Controls per standard. Procedure: Load each channel to 8 ohms. Inject a

SMPTE standard IM signal (60 Hz and 7 kHz sine wave mixed at 4:1 ratio) at 200 Watts (32.4 VAC). With an IM analyzer measure less than 0.01% IMD. Repeat test at –35 dB (reference 200 Watts or 32.4 VAC) and measure less than 0.05% IMD.

Figure 4. ODEP Limiting Wave Form

TEST 20: CLIPPING

Spec: No protective action during test. Initial Conditions: Controls per standard. Procedure: Load each channel to 8 ohms. Inject a 1 kHz

sine wave at each input and drive output 6 dB into clip for 10 seconds. The amplifier should not activate any protective circuits (ODEP, Fault, or LF Protection).

POST TESTING

After completion of testing, if all tests are satisfactory, the amplifier controls should be returned to the positions required by customer. If conditions are unknown or unspecified, factory settings are as follows:

Page 13

Power Base-1 & 460CSL Amplifier Service Manual

Mechanical (Non-Module) Parts

SUPPLIMENTAL ITEMS

CPN ITEM QTY

D 4137-2 Nylon Thumbscrew Washer 4 C 3342-0 Feet, Black Self-Stick 4 A10087-71012 10-32 .75 Machine (Rack Screw) 4

120VAC/60HZ NORTH AMERICA PRODUCT ONLY

CPN ITEM QTY

A10285-26 Fuse, 10A 3AB (120V Units) 1 A10285-7 Fuse, .5A AGC 1.25x.25 (LVPS) 1 D 6589-2 PB-1 Power Transformer 1 A10101-19 Washer, Fiber (XFMR Assby) 2 H42873-2 Fanformer Assembly 1 P10391-4 Fuse Board (U.S. Only) 1 P10426-6 Fuse Board (International Only) 1

FANFORMER MECHANICAL ASSEMBLY

CPN ITEM QTY

C 7062-0 Screw, 6-32-5/16 Flat Mach 2 C 9939-7 Fan Blade, 4 inch CCW 1 D 8439-8 Fan Bracket 1

FILTER CAPACITOR MOUNTING ASSEMBLY (ONE PER CHANNEL)

CPN ITEM QTY

A10095-4 Washer, #10 Ext. Lock 2 A10098-5 Belleville Spring Washer 2 C 7015-8 C126/C226 7800µF 90V 1 C 8752-5 D117/D217 35A 400V Bridge Rectifier 1 C 9870-4 Screw, 10-32-.38 Pan 2 D 6764-1 Washer, Shoulder 2 D 8438-0 Bracket, Capacitor Mounting 1

FUSE BOARD ASSEMBLY

CPN ITEM QTY

C 5060-6 Fuse Clip, PC Mount #926 4 P10391-4 Fuse Board 1

LED ASSEMBLY

CPN ITEM QTY

C 4342-9 Enable LED, Amber 1 P10068B4 LED Board 1

Page 14

Power Base-1 & 460CSL Amplifier Service Manual

Mechanical (Non-Module) Parts

OUTPUT ASSEMBLY (ONE PER CHANNEL)

CPN ITEM QTY

A10100-4 Washer, #6 Flat Zinc 2 A10315-1 Screw, 6-32-.56 Hex Washer Head 12 C 4751-1 NPN Output Device 2 C 5826-0 S100/S200 Thermal Sense LM334Z 1 C 6492-0 PNP Output Device 2 C 7326-9 Solder Lug, #6 Tin 2 C 8573-5 PNP Driver Device TO-3P 2 C 8574-3 NPN Driver Device TO-3P 2 C 8813-5 Q318/Q418 Bias Servo MPSA18/MPS8097 1 C 9491-9 Screw, 6-32-.312 Taptite Pan Ph 13 D 7665-9 Clip, TO-3P Mounting 2 D 7666-7 Bracket, TO-3P Heatsink 2 D 7796-2 Silpad Insulator 1 D 7797-0 Output Thru-Hole Pad Insulator 1 D 8264-0 PTC Thermal Sensor 1 F12019-0 Diode Heatsink Slug 1 F12469-7 Heatsink, Aluminum 2

Output Module (See Module List) 1

BACK PANEL ASSEMBLY

CPN ITEM QTY

A10214-7 Strain Relief (Power Cord) 1 C 2823-0 Dual Binding Post Assembly 1 D 7074-4 Power Cord (3-14 15A USA) 1 M21208J9 Back Panel 1 A10019-8 Nut, #8 32-2 Captive 2

CHASSIS FRONT ASSEMBLY

CPN ITEM QTY

A10031-1 Nut, 8-32 Captive 4 A10090-70806 Screw, 8-32-.375 Mach Ph Oval (Grille) 3 A10090-70808 Screw, 8-32-.5 Mach Ph Oval 4 A10101-5 Washer, Nylon (Grille) 3 A10110-70605 Screw, 6-32-.312 Taptite Ph (Cover) 20 A10173-1 Clip, Grille Filter 3 D 6944-9 Air Filter 1 D 8465J2 End Cap 2 D 8501-5 Cover , Top 1 D 8548-6 Cover, Bottom 1 F10962-3 Front Panel Overlay PB-1 1 F11978J7 Front Panel Overlay 460CSL 1 F12435J7 Grille 1

Page 15

Power Base-1 & 460CSL Amplifier Service Manual

Mechanical (Non-Module) Parts

MAIN CHASSIS ASSEMBLY

CPN ITEM QTY

A10086-11008 Screw, 10-32-.5 Mach Rd Ph 4 A10086-70806 Screw, 8-32-.37 Mach Rd Ph 2 A10089-11032 Screw, 10-32-2 Mach Pan Ph 4 A10094-3 Washer, #6 Black Star 3 A10094-6 Washer, #8 Black Star 4 A10094-8 Washer, #10 Tooth Lock 10 A10099-7 Washer, #10 Nylon Shoulder 4 A10100-16 Washer 4 A10102-8 Nut, 10-32 Hex Zinc 6 A10109-10822 Screw, 8-18-1.375 Pan Ph 2 A10110-70812 Screw, 8-32-.75 Taptite Pan Ph 2 A10192-1 Snap Bushing .5 4 C 1811-6 Tie Wrap 4 C 3163-0 Solder Lug #6 505 1 C 6487-0 Power Switch 22A Rocker 2 Pole 1 C 6912-7 Tension Retainer Board Support 2 C 6913-5 Spacer Nut, 1 inch 2 C 6914-3 Spacer Nut, .75 inch 2 C 9491-9 Screw, 6-32-.312 Taptite Pan 4 C 9953-8 Screw, 6-20-.312 Taptite Pan Black 6 D 7340-9 Label, F1 Fuse Replacement 1 D 7600-6 Ground Strap (DBP to Chassis) 1 D 7784-8 Label, Sensitivity Switch 1 D 8003-2 Label, F200 Fuse Replacement 1 D 8069-4 Insulator, Fuse Board 1 F10787J3 Back Panel Plate 1 F10963-1 Transformer Plate 1 M21059J6 Chassis 1

Main Module (See Module List) 1

Page 16

Power Base-1 & 460CSL Amplifier Service Manual

Module Information

MODULE HISTORY

Since its introduction in 1986, the PB-1 has gone through a number of updates and revisions. Over the course of its history some of these changes have resulted in upgrading to newer modules. What follows is a historical breakdown of PB-1 modules. It should also be noted that the 460CSL was introduced in 1992 and therefor modules obsoleted before that time were never used in the CSL version.

OUTPUT MODULES:

Q42576-1 Original output module. No longer available. Q42661-1 Through hole output module. No longer available. Q42718-9 Output module: 4 resistor small predriver. PB-1 Only. Last output module for PB-1 for use with TO-220 package driver transistors. Q42885-6 TO-3P Driver Output module. Not for use in THC units, not retrofittable into TO-220 driver transistor units. Q42967-2 THC Output module with TO-3P drivers. Not retrofittable to any older units. Does not require special main module for THC ODEP recompensation. Also improved bias stability. Q43200-7 THC #2 Output Module. Replaces Q42967-2 only. Electrically identical, but larger screw head plates prevent shorting which could occur with the first THC output module.

MAIN MODULES:

Q42552A0 This was the original main board. It offered 2 front end gain stages and was also used in the PB-1, MT-600/ LX, MT-1200/LX. It did not include ground lift, but did offer a choice of .775V or 26 dB voltage gain sensitivities. No longer available. Q42664-5 Service replacement for Q42552A0 for PB-1. No longer available. Q42682-7 Main #2. Upgraded board from Q42552A0 for PB-1. No longer available. Q42776-7 Universally usable PC board, finished module used in MT-600/1200, MA-600/1200, and PB-1. Added third gain stage and ground lift switch. For use in the PB-1 install two level pots (C 7409-3) and remove R187 and R287. Can replace all older modules. Use this module to replace this or any previous module. This module can also be used to replace the Q42953-2 module put into production later. Note that if this module is being used to replace an older module, you may have to slide the ground lift switch to the left (ground lift position) and clip off the plastic switch protrusion in order for the module to properly fit in the unit. Q42953-2 PB-1 main module to replace Q42776-7. This or the Q42776-7 module may be used with TO-3P driver transistor output modules, and with or without Through Hole Chassis (THC) in this amplifier. Q43060-5 THC main module built on D 7993-5 circuit board. On this module the boost circuit has been deleted, the third position (1.4V) is added to the Sensitivity Switch, and additional fault circuitry has been added to the module. Although it is possible to modify any older unit to accept this module, it is recommended that the Q42776-7 be used to replace main modules in all older units, and this module be used only as a replacement for itself.

Page 17

Power Base-1 & 460CSL Amplifier Service Manual

Q42576-1 Output Module Parts List (P10137-1 Board)

Q42576-1 Output Module (4 Resistor Original) for PB-1:

CAPACITORS

C01 C 3978-1 .047µF C02 C 6804-6 .1µF C03 C 6804-6 .1µF C04 C 3996-3 .0047µF C05 C 6807-9 .001µF C06 C 6806-1 .01µF C07 C 6807-9 .001µF C08 C 6810-3 180pF C09 C 6809-5 220pF C43 C 6806-1 .01uF

DIODES

D01 C 2851-1 1N4004 D02 C 2851-1 1N4004 D03 C 2851-1 1N4004 D04 C 2851-1 1N4004 D05 C 2851-1 1N4004 D06 C 2851-1 1N4004 D07 C 2851-1 1N4004 D08 C 2851-1 1N4004 D09 C 2851-1 1N4004 D10 C 2851-1 1N4004 D11 C 2851-1 1N4004 D12 C 2851-1 1N4004

INDUCTORS

L00 C 6592-6 Output Coil L01 C 3510-2 470µH L02 C 3510-2 470µH

TRANSISTORS

Q17 C 3810-6 NPN MPSA43 Q19 C 3578-9 PNP MPSA93

RESISTORS

R00 A10266-7501 75 R01 A10266-4711 470 R02 C 7778-1 5.6 R03 C 6486-2 .2 5W R08 C 6486-2 .2 5W R09 C 7779-9 22 R10 A10266-4711 470 R11 C 1001-4 2.7 1W R12 C 1001-4 2.7 1W R13 A10266-7501 75 R14 C 1001-4 2.7 1W R15 C 6486-2 .2 5W R20 C 6486-2 .2 5W R21 C 7778-1 5.6 R22 C 7779-9 22 R23 C 6844-2 250 Pot LS Bias R24 A10266-1331 13K R25 A10266-2221 2.2K R26 C 6844-2 250 Pot HS Bias R27 A10266-3911 390 R28 A10266-1331 13K R30* A10265-10201* 102*

MISC.

Board P10137-1 Jumpers C 5868-2 0 Ohm Jumper (8) Clips D 6414-3 Q17/19 Hold Down J500 J600 C 7057-0 10 Pos. Connector

Note: R30 is 102 Ohms in most units, though in some cases a different value may be used to match the installed S100/S200 LM334 (C5826-0) device grade. This is the standard value and is used with the most common LM334 grade, green. If the LM334 is marked with a blue dot, R30 should be a 107 Ohm resistor (A10265-10701); if it is marked with a yellow dot then R30 should be a 100 Ohm resistor (A10265-10001).

Page 18

Power Base-1 & 460CSL Amplifier Service Manual

Q42661-1 Output Module Parts List (P10137-1 Board)

Q42661-1 Output Module (4 Resistor #2) for PB-1:

CAPACITORS

C01 C 3978-1 .047µF C02 C 6804-6 .1µF C03 C 6804-6 .1µF C04 C 3996-3 .0047µF C05 C 6807-9 .001µF C06 C 6806-1 .01µF C07 C 6807-9 .001µF C08 C 6810-3 180pF C09 C 6809-5 220pF

DIODES

INDUCTORS

L00 C 6592-6 Output Coil L01 C 3510-2 470µH L02 C 3510-2 470µH

TRANSISTORS

Q17 C 3810-6 NPN MPSA43 Q19 C 3578-9 PNP MPSA93

RESISTORS

R00 A10266-7501 75 R01 A10266-4711 470 R02 C 7778-1 5.6 R07 D 6600-7 .19 5W R09 C 7779-9 22 R10 A10266-4711 470 R11 C 1001-4 2.7 1W R12 C 1001-4 2.7 1W R13 A10266-7501 75 R14 C 1001-4 2.7 1W R15 D 6600-7 .19 5W R16 D 6600-7 .19 5W R19 D 6600-7 .19 5W R21 C 7778-1 5.6 R22 C 7779-9 22 R23 C 6844-2 250 Pot LS Bias R24 A10266-1331 13K R25 A10266-2221 2.2K R26 C 6844-2 250 Pot HS Bias R27 A10266-3911 390 R28 A10266-1331 13K R30* A10265-10201* 102*

MISC.

Board P10137-1 Jumpers C 5868-2 0 Ohm Jumper (4) Clips D 6414-3 Q17/19 Hold Down J500 J600 C 7057-0 10 Pin Header

Page 19

Power Base-1 & 460CSL Amplifier Service Manual

Q42718-9 Output Module Parts List (P10233-8 Board)

Q42718-9 Output Module (4 Resistor #3) for PB-1:

CAPACITORS

C01 C 3978-1 .047µF C02 C 3218-2 .22µF C03 C 3218-2 .22µF C04 C 8534-7 .0047µF C05 C 6807-9 .001µF C06 C 6806-1 .01µF C07 C 6807-9 .001µF C08 C 6810-3 180pF C09 C 6809-5 220pF

DIODES

INDUCTORS

L00 C 6592-6 1.3µH Output Coil L01 C 3510-2 470µH L02 C 3510-2 470µH

TRANSISTORS

Q17 C 3810-6 NPN MPSA43/42 Q19 C 3578-9 PNP MPSA93

RESISTORS

R00 A10266-7501 75 R01 A10266-4711 470 R07 D 6600-7 .19 5W R10 A10266-4711 470 R11 A10266-2R73 2.7 1W R12 A10266-1204 12 2W R13 A10266-7501 75 R14 A10266-1204 12 2W R15 D 6600-7 .19 5W R16 D 6600-7 .19 5W R19 D 6600-7 .19 5W R23 C 6844-2 250 Pot LS Bias R24 A10266-1331 13K R25 A10266-2221 2.2K R26 C 6844-2 250 Pot HS Bias R27 A10266-3911 390 R28 A10266-1331 13K R30* A10265-10201* 102* R31 C 7778-1 5.6 .5W Flame Proof R32 C 7778-1 5.6 .5W Flame Proof R33 C 7779-9 22 .5W Flame Proof R34 C 7779-9 22 .5W Flame Proof R35 A10266-1204 12 2W R36 A10266-1204 12 2W R37 A10266-1204 12 2W R38 A10266-1204 12 2W R39 A10266-1204 12 2W R40 A10266-1204 12 2W

MISC.

Board P10233-8 Jumpers C 5868-2 0 Ohm .25W Clips D 6414-3 Q17/Q19 Hold Down J500 J600 C 7057-0 10 Pin Header

*Note: R30 is 102 Ohms in most units, though in some cases a different value may be used to match the installed S100/S200 LM334 (C5826-0) device grade. This is the standard value and is used with the most common LM334 grade, green. If the LM334 is marked with a blue dot, R30 should be a 107 Ohm resistor (A10265-10701); if it is marked with a yellow dot then R30 should be a 100 Ohm resistor (A10265-10001).

Page 20

Power Base-1 & 460CSL Amplifier Service Manual

Q42885-6 Output Module Parts List (P10305-4 Board)

Q42885-6 Output Module (4 Resistor TO-3P Drivers) for PB-1/460CSL:

CAPACITORS

C01 C 8511-5 .047µF C02 C 7964-7 .22µF C03 C 7964-7 .22µF C04 C 8534-7 .0047µF C05 C 6807-9 .001µF C06 C 6806-1 .01µF C07 C 6807-9 .001µF C08 C 6810-3 180pF C09 C 6809-5 220pF C43 C 6806-1 .01uF

DIODES

INDUCTORS

L00 C 6592-6 Output Coil L01 C 3510-2 470µH L02 C 3510-2 470µH

TRANSISTORS

Q17 C 3810-6 NPN MPSA43 Q19 C 3578-9 PNP MPSA93

RESISTORS

R00 A10266-7501 75 R01 A10266-4711 470 R04 D 6600-7 .19 5W R07 D 6600-7 .19 5W R10 A10266-4711 470 R11 C 1001-4 2.7 1W R12 C 3931-0 12 2W R13 A10266-7501 75 R16 D 6600-7 .19 5W R19 D 6600-7 .19 5W R23 C 6844-2 250 Pot LS Bias R24 A10266-1331 13K R25 A10266-2221 2.2K R26 C 6844-2 250 Pot HS Bias R27 A10266-3911 390 R28 A10266-1331 13K R29 C 6402-9 51 OHM R30* A10265-10201* 102* R31 C 7778-1 5.6 flame proof R32 C 7778-1 5.6 flame proof R33 C 7779-9 22 flame proof R34 C 7779-9 22 flame proof R35 C 3931-0 12 2W R36 C 3931-0 12 2W R37 C 3931-0 12 2W R38 C 3931-0 12 2W R39 C 3931-0 12 2W R40 C 3931-0 12 2W

MISC.

Board P10305-4 Jumpers C 5868-2 0 Ohm Jumper (7) Clips D 6414-3 Q17/19 Hold Down J500 J600 C 7057-0 10 Pos. Connector BEAD C 8341-7 Over emitter of Q19

Page 21

Power Base-1 & 460CSL Amplifier Service Manual

Q42967-2 Output Module Parts List (P10341-9 Board)

Q42967-2 Output Module for Through Hole Chassis (THC) PB-1/460CSL units:

CAPACITORS

C01 C 8511-5 .047µF C02 C 7964-7 .22µF C03 C 7964-7 .22µF C04 C 8534-7 .0047µF C05 C 8534-7 .0047µF C06 C 6806-1 .01µF C07 C 6807-9 .001µF C08 C 6810-3 180pF C09 C 6809-5 220pF C43 C 6806-1 .01µF

DIODES

INDUCTORS

L00 C 6592-6 Output Coil L01 C 3510-2 470µH L02 C 3510-2 470µH

TRANSISTORS

Q17 C 3810-6 NPN MPSA43 Q19 C 3578-9 PNP MPSA93

RESISTORS

R00 A10266-7501 75 R01 A10266-4711 470 R04 D 6600-7 .19 5W R07 D 6600-7 .19 5W R10 A10266-4711 470 R11 A10266-2R73 2.7 1W R12 A10266-1204 12 2W R13 A10266-7501 75 R14 A10266-1204 12 2W R16 D 6600-7 .19 5W R19 D 6600-7 .19 5W R23 C 6844-2 250 Pot LS Bias R24 A10266-1331 13K R25 A10266-2221 2.2K R26 C 6844-2 250 Pot HS Bias R27 A10266-3911 390 R28 A10266-1331 13K R29 A10266-5101 51 R30* A10265-10201* 102* R31 C 7778-1 5.6 .5W Flame Proof R32 C 7778-1 5.6 .5W Flame Proof R33 C 7779-9 22 .5W Flame Proof R34 C 7779-9 22 .5W Flame Proof R35 A10266-1204 12 2W R36 A10266-1204 12 2W R37 A10266-1204 12 2W R38 A10266-1204 12 2W R39 A10266-1204 12 2W R40 A10266-1204 12 2W

MISC.

Board P10341-9 Jumpers C 5868-2 0 Ohm (Qty 7) Clips D 6414-3 Q17/Q19 Hold Down J500 J600 C 7057-0 10 Pin Header

Page 22

Power Base-1 & 460CSL Amplifier Service Manual

Q43200-7 Output Module Parts List (P10397-1 Board)

Q43200-7 Output Module (THC #2) for PB-1/460CSL Units:

CAPACITORS

DIODES

INDUCTORS

L00 C 6592-6 Output Coil L01 C 3510-2 470µH L02 C 3510-2 470µH

TRANSISTORS

Q17 C 3810-6 NPN MPSA43 Q19 C 3578-9 PNP MPSA93

RESISTORS

R00 A10266-7501 75 R01 A10266-4711 470 R04 D 6600-7 .19 5W R07 D 6600-7 .19 5W R10 A10266-4711 470 R11 A10266-2R73 2.7 1W R12 A10266-1204 12 2W R13 A10266-7501 75 R14 A10266-1204 12 2W R16 D 6600-7 .19 5W R19 D 6600-7 .19 5W R23 C 6844-2 250 Pot LS R24 A10266-1331 13K R25 A10266-2221 2.2K R26 C 6844-2 250 Pot HS R27 A10266-3911 390 R28 A10266-1331 13K R29 A10266-5101 51 R30* A10265-10201* 102* R31 C 7778-1 5.6 .5W Flame Proof R32 C 7778-1 5.6 .5W Flame Proof R33 C 7779-9 22 .5W Flame Proof R34 C 7779-9 22 .5W Flame Proof R35 A10266-1204 12 2W R36 A10266-1204 12 2W R37 A10266-1204 12 2W R38 A10266-1204 12 2W R39 A10266-1204 12 2W R40 A10266-1204 12 2W

MISC.

Board P10397-1 Jumpers C 5868-2 0 Ohm (Qty 7) Clips D 6414-3 Q17/Q19 Hold Down J500 J600 C 7057-0 10 Pin Header

Page 23

Power Base-1 & 460CSL Amplifier Service Manual

Q42552A0 Main Module Parts List (D 6304B2 Board)

Q42552A0 Main Module (Original) for PB-1:

CAPACITORS

C1 C 4303-1 1000uF C2 C 3913-8 470uF C3 C 4303-1 1000uF C4 C 6802-0 .47uF C100 C200 C 5053-1 18uF C101 C201 C 2821-4 10pF C103 C203 C 6805-3 .022uF C104 C204 C 6805-3 .022uF C105 C205 C 6950-7 82pF C106 C206 C 6950-7 82pF C108 C208 C 6812-9 47pF C112 C212 C 6803-8 .12uF C113 C213 C 6802-0 .47uF C114 C214 C 3729-8 100uF 16V C115 C215 C 3729-8 100uF 16V C116 C216 C 6802-0 .47uF C117 C217 C 6803-8 .12uF C118 C218 C 6812-9 47pF C122 C222 C 6811-1 100pF C124 C224 C 6809-5 220pF C125 C225 C 3729-8 100uF 16V C127 C227 C 3729-8 100uF 16V C133 C233 C 6814-5 12pF C134 C234 C 6805-3 .022uF C135 C235 C 6805-3 .022uF C136 C236 C 6808-7 470pF C137 C237 C 6808-7 470pF C138 C238 C 6814-5 12pF C139 C239 C 6814-5 12pF C140 C240 C 6812-9 47pF C141 C241 C 6812-9 47pF C142 C242 C 5162-0 3-12pF Trim

D112 D212 C 3181-2 1N4148 D113 D213 C 3181-2 1N4148 D114 D214 C 3181-2 1N4148 D115 D215 C 3181-2 1N4148 D120 D220 C 3181-2 1N4148 D121 D221 C 3181-2 1N4148 D122 D222 C 3181-2 1N4148 D123 D223 C 3181-2 1N4148

NETWORK RESISTORS

N100 N200 D 4669-4 Balanced Input Trim N101 N201 D 6081-0 Resistor Network-B N102 N202 D 6082-8 Resistor Network-C

TRANSISTORS

Q100 Q200 D 2961-7 SEL 2N3859A Q101 Q201 C 3578-9 MPSA93 Q102 Q202 C 3810-6 MPSA43/A42 Q103 Q203 C 3786-8 PN4250A Q104 Q204 C 3625-8 2N4125 Q105 Q205 C 3578-9 MPSA93 Q106 Q206 C 3625-8 2N4125 Q107 Q207 C 3786-8 PN4250A Q108 Q208 D 2961-7 SEL 2N3859A Q109 Q209 D 2961-7 SEL 2N3859A Q110 Q210 C 3810-6 MPSA43/A42 Q111 Q211 D 2961-7 SEL 2N3859A Q112 Q212 C 3625-8 2N4125 Q113 Q213 C 3625-8 2N4125 Q115 Q215 D 2962-5 MPS8097 Q116 Q216 C 3786-8 PN4250A Q117 Q217 D 2961-7 SEL 2N3859A Q118 Q218 D 2961-7 SEL 2N3859A Q119 Q219 C 3625-8 2N4125 Q120 Q220 C 3625-8 2N4125

DIODES

RESISTORS

R1 A10265-10031 100K 1% R5 A10266-3321 3.3K R100 R200 C 6893-9 5K POT R101 R201 A10265-49911 4.99K R102 R202 A10266-1021 1K R103 R203 A10265-10031 100K 1% R104 R204 A10266-2721 2.7K R105 R205 A10266-2721 2.7K R106 R206 A10266-1231 12K R107 R207 A10266-4731 47K R108 R208 A10266-1021 1K R109 R209 A10266-8201 82 OHM R110 R210 A10266-4731 47K R112 R212 A10266-5131 51K R113 R213 A10266-4721 4.7K

Page 24

Power Base-1 & 460CSL Amplifier Service Manual

Q42552A0 Main Module Parts List (D 6304B2 Board)

R114 R214 A10266-4721 4.7K R115 R215 A10266-5141 510K R116 R216 A10266-3351 3.3M R118 R218 A10266-2711 270 OHM R119 R219 A10266-3011 300 OHM R120 R220 A10266-2711 270 OHM R121 R221 C 5062-2 100K TRIMMER R122 R222 A10266-2741 270K R123 R223 A10266-1831 18K R124 R224 A10266-6821 6.8K R125 R225 C 7782-3 100 OHM R126 R226 C 7782-3 100 OHM R127 R227 A10266-6821 6.8K R128 R228 A10266-1031 10K R129 R229 A10266-1041 100K R130 R230 A10266-1041 100K R131 R231 A10266-1031 10K R132 R232 C 5062-2 100K TRIMMER R133 R233 A10266-2741 270K R134 R234 A10266-1831 18K R135 R235 C 7782-3 100 OHM R136 R236 A10266-6821 6.8K R137 R237 C 7782-3 100 OHM R138 R238 A10266-6821 6.8K R139 R239 A10266-1021 1K R140 R240 A10266-8201 82 OHM R141 R241 A10266-1541 150K R142 R242 A10266-1541 150K R146 R246 A10266-1031 10K R147 R247 C 7781-5 200 OHM R148 R248 A10266-2721 2.7K R149 R249 C 7781-5 200 OHM R150 R250 A10266-2721 2.7K R151 R251 A10266-1031 10K R152 R252 A10266-1231 12K R154 R254 A10266-1011 100 OHM R156 R256 A10266-1321 1.3K R157 R257 A10266-1321 1.3K R158 R258 A10266-9121 9.1K R159 R259 A10266-1031 10K R161 R261 A10266-4701 47 OHM R162 R262 A10266-4701 47 OHM R165 R265 A10265-53611 5.36K 1% R146 R246 A10265-53611 5.36K 1% R167 R267 A10266-1021 1K R168 R268 A10265-95301 953 OHM R170 R270 A10266-1021 1K R171 R271 A10265-95301 953 OHM

SWITCHES

S3 C 6841-8 4PDT S100 C 6781-6 6P3T

IC’S

U1 C 5095-2 MC7815 U2 C 5096-0 MC7915 U100 U200 C 6500-0 UPA77 PNP U103 U203 C 6910-1 UPA76 NPN U104 U204 C 6900-2 MC34084P

MISC.

Board D 6304A4 or D 6304B2 J9 C 6871-5 6-Cond Snap Mate J100 J200 C 6777-4 PHONE JACK J500 J800 D 6619-7 10" RIBBON ASSY J600 J700 D 6620-5 6" RIBBON ASSY MOUNTS U1, U2:

(2) C 1889-2 6-32 NUT (2) C 2176-3 6-32 X .5 SCREW (2) C 5341-0 HEATSINK (2) C 5594-4 STAR WASHER

MOUNTS U104, U204:

(2) C 3450-1 14 Pin Socket

COVERS FOR J100, J200:

(2) C 6778-2 Cover, Phone Jack

Additional Parts

(1) C 4508-5 16 PIN SOCKET (1) C 5061-4 1N3070 DIODE (1) C 6851-7 5-Pos Header (1) C 7077-8 3-Cond Wire Retain

C 6899-6 Wire Posts

Page 25

Power Base-1 & 460CSL Amplifier Service Manual

Q42664-5 Main Module Parts List (D 6910-0 Board)

Q42664-5 Main Module (Service Replacement For Original) for PB-1:

CAPACITORS

C1 C 4303-1 1000uF C2 C 3913-8 470uF C3 C 4303-1 1000uF C4 C 6802-0 .47uF C100 C200 C 5311-3 22uF C101 C201 C 2821-4 10pF C103 C203 C 6805-3 .022uF C104 C204 C 6805-3 .022uF C105 C205 C 6950-7 82pF C106 C206 C 6950-7 82pF C108 C208 C 6812-9 47pF C112 C212 C 6803-8 .12uF C113 C213 C 6802-0 .47uF C114 C214 C 3729-8 100uF 16V C115 C215 C 3729-8 100uF 16V C116 C216 C 6802-0 .47uF C117 C217 C 6803-8 .12uF C118 C218 C 6812-9 47pF C122 C222 C 6811-1 100pF C123 C223 C 6811-1 100pF C124 C224 C 6809-5 220pF C125 C225 C 3729-8 100uF 16V C127 C227 C 3729-8 100uF 16V C128 C228 C 6803-8 .12uF C133 C233 C 6814-5 12pF C134 C234 C 6805-3 .022uF C135 C235 C 6805-3 .022uF C136 C236 C 6808-7 470pF C137 C237 C 6808-7 470pF C138 C238 C 6814-5 12pF C139 C239 C 6814-5 12pF C140 C240 C 6812-9 47pF C141 C241 C 6812-9 47pF

C242 C 5162-0 3-12pF Trim

D109 D209 C 3181-2 1N4148 D110 D210 C 3181-2 1N4148 D111 D211 C 5061-4 1N3070 D112 D212 C 3181-2 1N4148 D113 D213 C 3181-2 1N4148 D114 D214 C 3181-2 1N4148 D115 D215 C 3181-2 1N4148 D120 D220 C 3181-2 1N4148 D121 D221 C 3181-2 1N4148 D122 D222 C 3181-2 1N4148 D123 D223 C 5061-4 1N3070

NETWORK RESISTORS

N100 N200 D 4669-4 Balanced Input Trim N101 N201 D 6081-0 Resistor Network-B N102 N202 D 6082-8 Resistor Network-C

TRANSISTORS

DIODES

RESISTORS

R1 A10265-10031 100K 1% R5 A10266-3323 3.3K 1W R100 R200 C 6893-9 5K POT R101 R201 A10265-49911 4.99K R102 R202 A10266-1021 1K R103 R203 A10265-10031 100K 1% R104 R204 A10266-2721 2.7K R105 R205 A10266-2721 2.7K R106 R206 A10266-1231 12K R107 R207 A10266-4731 47K R108 R208 A10266-1021 1K R109 R209 A10266-8201 82 OHM

Page 26

Power Base-1 & 460CSL Amplifier Service Manual

Q42664-5 Main Module Parts List (D 6910-0 Board)

R110 R210 A10266-4731 47K R111 R211 A10266-1231 12K R112 R212 A10266-5131 51K R113 R213 A10266-4721 4.7K R114 R214 A10266-4721 4.7K R115 R215 A10266-5141 510K R116 R216 A10266-3351 3.3M R117 R217 A10266-4731 47K R118 R218 A10266-2711 270 OHM R119 R219 A10266-3011 300 OHM R120 R220 A10266-2711 270 OHM R121 R221 C 5062-2 100K TRIMMER R122 R222 A10266-2741 270K R123 R223 A10266-1831 18K R124 R224 A10266-6821 6.8K R125 R225 C 7782-3 100 OHM R126 R226 C 7782-3 100 OHM R127 R227 A10266-6821 6.8K R128 R228 A10266-1031 10K R129 R229 A10266-1041 100K R130 R230 A10266-1041 100K R131 R231 A10266-1031 10K R132 R232 C 5062-2 100K TRIMMER R133 R233 A10266-2741 270K R134 R234 A10266-1831 18K R135 R235 C 7782-3 100 OHM R136 R236 A10266-6821 6.8K R137 R237 C 7782-3 100 OHM R138 R238 A10266-6821 6.8K R139 R239 A10266-1021 1K R140 R240 A10266-8201 82 OHM R141 R241 A10266-1541 150K R142 R242 A10266-1541 150K R146 R246 A10266-1031 10K R147 R247 C 7781-5 200 OHM R148 R248 A10266-2721 2.7K R149 R249 C 7781-5 200 OHM R150 R250 A10266-2721 2.7K R151 R251 A10266-1031 10K R152 R252 A10266-1231 12K R154 R254 A10266-1011 100 OHM R156 R256 A10266-1321 1.3K R157 R257 A10266-1321 1.3K R158 R258 A10266-9121 9.1K

R159 R259 A10266-1031 10K R161 R261 A10266-4701 47 OHM R162 R262 A10266-4701 47 OHM R165 R265 A10265-53611 5.36K 1% R146 R246 A10265-53611 5.36K 1% R167 R267 A10266-1021 1K R168 R268 A10265-95301 953 OHM R170 R270 A10266-1021 1K R171 R271 A10265-95301 953 OHM

SWITCHES

S3 C 6841-8 4PDT S100 C 6781-6 6P3T

IC’S

U1 C 5095-2 MC7815 U2 C 5096-0 MC7915 U100 U200 C 6911-9 UPA75 PNP U103 U203 C 6910-1 UPA76 NPN U104 U204 C 6900-2 MC34084P

MISC.

BOARD D 6304B2 J1 C 7593-4 5 PIN HEADER J2 C 4508-5 16 PIN SOCKET J9 C 7527-2 6 PIN HEADER J10 C 7592-6 4 PIN HEADER J11 C 7077-8 WIRE RET AINER J100 J200 C 6777-4 PHONE JACK J500 J800 D 6619-7 10" RIBBON ASSY J600 J700 D 6620-5 6" RIBBON ASSY MOUNTS U1, U2:

(2) C 1889-2 6-32 NUT (2) C 2176-3 6-32 X .5 SCREW (2) C 5341-0 HEATSINK (2) C 5594-4 STAR WASHER

MOUNTS U104, U204:

(2) C 3450-1 14 Pin Socket

COVERS FOR J100, J200:

(2) C 6778-2 Cover, Phone Jack

Additional Parts

(1) C 7077-8 3-Cond Wire Retain

Page 27

Power Base-1 & 460CSL Amplifier Service Manual

Q42682-7 Main Module Parts List (D 6910-0 Board)

Q42682-7 Main Module (#2) for PB-1:

CAPACITORS

C1 C 4303-1 1000uF C2 C 3913-8 470uF C3 C 4303-1 1000uF C4 C 6802-0 .47uF C5 OPEN C6 OPEN C100 C200 C 5311-3 22uF C101 C201 C 2820-6 5pF C103 C203 C 6805-3 .022uF C104 C204 C 6805-3 .022uF C105 C205 C 6812-9 47pF C106 C206 C 6812-9 47pF C108 C208 C 6814-5 12pF C112 C212 C 6803-8 .12uF C113 C213 C 6802-0 .47uF C114 C214 C 3729-8 100uF 16V C115 C215 C 3729-8 100uF 16V C116 C216 C 6802-0 .47uF C117 C217 C 6803-8 .12uF C118 C218 C 6814-5 12pF C122 C222 C 6811-1 100pF C123 C223 C 6812-9 47pF C124 C224 C 6812-9 47pF C125 C225 C 3729-8 100uF 16V C127 C227 C 3729-8 100uF 16V C128 C228 C 7706-2 .1uF C129 OPEN C130 C 6814-5 12pF C133 C233 C 6814-5 12pF C134 C234 C 6805-3 .022uF C135 C235 C 6805-3 .022uF C136 C236 C 6808-7 470pF C137 C237 C 6808-7 470pF C138 C238 C 6814-5 12pF C139 C239 C 6814-5 12pF C140 C240 C 6812-9 47pF C141 C241 C 6812-9 47pF

C242 C 5162-0 3-12pF Trim C144 C244 C 5362-6 2.2uF C145 C245 C 6814-5 12pF C146 C246 C 6809-5 220pF C147 C247 C 6806-1 .01uF C148 C248 C 6810-3 180pF C149 C249 C 6808-7 470pF C150 C250 OPEN C151 C251 OPEN C152 C252 C 6809-5 220pF C153 C253 C 5362-6 2.2uF

DIODES

D1 C 2851-1 1N4004 D2 C 2851-1 1N4004 D3 C 2851-1 1N4004 D4 C 2851-1 1N4004 D5 C 2851-1 1N4004 D6 C 2851-1 1N4004 D7 C 2851-1 1N4004 D104 D204 C 2851-1 1N4004 D105 D205 C 2851-1 1N4004 D106 D206 C 2851-1 1N4004 D107 D207 C 2851-1 1N4004 D108 D208 C 3181-2 1N4148 D109 D209 C 3181-2 1N4148 D110 D210 C 3181-2 1N4148 D111 D211 C 5061-4 1N3070 D112 D212 C 3181-2 1N4148 D113 D213 C 3181-2 1N4148 D114 D214 C 3181-2 1N4148 D115 D215 C 3181-2 1N4148 D120 D220 C 3181-2 1N4148 D121 D221 C 3181-2 1N4148 D122 D222 C 3181-2 1N4148 D123 D223 C 5061-4 1N3070

NETWORK RESISTORS

N100 N200 D 4669-4 Balanced Input Trim N101 N201 D 6081-0 Resistor Network-B N102 N202 D 6082-8 Resistor Network-C

TRANSISTORS

Page 28

Power Base-1 & 460CSL Amplifier Service Manual

Q42682-7 Main Module Parts List (D 6910-0 Board)

RESISTORS

R1 A10265-53621 53.6K 1% R2 OPEN R3 OPEN R4 A10265-46421 46.4K 1% R5 A10266-3323 3.3K 1W R10 OPEN R100 R200 C 7409-3 5K POT R101 R201 A10265-49911 4.99K R102 R202 A10266-1021 1K R103 R203 A10265-10031 100K 1% R104 R204 A10266-2721 2.7K R105 R205 A10266-2721 2.7K R106 R206 A10266-1231 12K R107 R207 A10266-6831 68K R108 R208 A10266-1021 1K R109 R209 A10266-8201 82 OHM R110 R210 A10266-6831 68K R111 R211 A10266-1231 12K R112 R212 A10266-5131 51K R113 R213 A10266-4721 4.7K R114 R214 A10266-4721 4.7K R115 R215 A10266-5141 510K R116 R216 A10266-3351 3.3M R117 R217 A10266-4731 47K R118 R218 A10266-2711 270 OHM R119 R219 A10266-3011 300 OHM R120 R220 A10266-2711 270 OHM R121 R221 C 5062-2 100K TRIMMER R122 R222 A10266-2741 270K R123 R223 A10266-1831 18K R124 R224 A10266-6821 6.8K R125 R225 C 7782-3 100 OHM R126 R226 C 7782-3 100 OHM R127 R227 A10266-6821 6.8K R128 R228 A10266-1031 10K R129 R229 A10266-1041 100K R130 R230 A10266-1041 100K R131 R231 A10266-1031 10K R132 R232 C 5062-2 100K TRIMMER R133 R233 A10266-2741 270K R134 R234 A10266-1831 18K R135 R235 C 7782-3 100 OHM R136 R236 A10266-6821 6.8K R137 R237 C 7782-3 100 OHM R138 R238 A10266-6821 6.8K R139 R239 A10266-1021 1K R140 R240 A10266-8201 82 OHM R141 R241 A10266-1541 150K R142 R242 A10266-1541 150K R146 R246 A10266-1031 10K R147 R247 C 7781-5 200 OHM

R148 R248 A10266-2721 2.7K R149 R249 C 7781-5 200 OHM R150 R250 A10266-2721 2.7K R151 R251 A10266-1031 10K R152 R252 A10266-1231 12K R153 R253 C 5869-2 ZERO OHM R155 R255 OPEN R156 R256 A10266-1321 1.3K R157 R257 A10266-1321 1.3K R158 R258 A10266-9121 9.1K R159 R259 A10266-1031 10K R161 R261 A10266-4701 47 OHM R162 R262 A10266-4701 47 OHM R167 R267 A10266-1021 1K R168 R268 A10265-95301 953 OHM R169 R269 OPEN R170 R270 A10266-1021 1K R171 R271 A10265-95301 953 OHM R172 R272 OPEN R174 R274 A10265-38311 3.83K 1% R175 R275 A10265-24311 2.43K 1% R176 R276 A10266-1041 100K R177 R277 C 5062-2 TRIM POT R178 R278 A10266-1231 12K R179 R279 A10266-4731 47K R180 R280 A10266-4711 470 OHM R181 R281 A10266-4721 4.7K R182 R282 A10266-2201 22 OHM R183 R283 A10266-2051 2M

SWITCHES

S3 C 7363-2 4PDT S100 C 6781-6 6P3T

IC’S

U1 C 5095-2 MC7815 U2 C 5096-0 MC7915 U100 U200 C 6911-9 UPA75 PNP U103 U203 C 6910-1 UPA76 NPN U104 U204 C 6900-2 MC34084P

INTERCONNECTS

J1 OPEN J2 C 4508-5 16 PIN SOCKET J9 C 7527-2 6 PIN HEADER J10 C 7592-6 4 PIN HEADER J11 C 7526-4 3 PIN HEADER J100 J200 C 6777-4 PHONE JACK J500 J800 D 6619-7 10" RIBBON ASSY J600 J700 D 6620-5 6" RIBBON ASSY

Page 29

Q42682-7 Main Module Parts List (D 6910-0 Board)

MISC.

BOARD D 6910-0 MOUNTS U1, U2:

(2) C 1889-2 6-32 NUT

(2) C 2176-3 6-32 X .5 SCREW

(2) C 5341-0 HEATSINK

(2) C 5594-4 STAR WASHER MOUNTS U104, U204:

(2) C 3450-1 14 PIN SOCKET COVERS FOR J100, J200:

(2) C 6778-2 Phone Jack Cover STRAIN RELIEF:

(4) C 1811-6 CABLE TIE

Power Base-1 & 460CSL Amplifier Service Manual

Page 30

Power Base-1 & 460CSL Amplifier Service Manual

Q42776-7 Main Module Parts List (D 7251-8 Board)

Q42776-7 Main Module (3rd Gain) for PB-1:

CAPACITORS

C1 C 3913-8 470uF C2 C 3913-8 470uF C4 C 6802-0 .47uF C5 C 6806-1 .01uF C6 C 6806-1 .01uF C7 C 6094-9 33uF C8 C 6806-1 .01uF C100 C200 C 5311-3 22uF C101 C201 C 2820-6 5pF C103 C203 C 6805-3 .022uF C104 C204 C 6804-6 .1uF C105 C205 C 6812-9 47pF C106 C206 C 6812-9 47pF C108 C208 C 6814-5 12pF C112 C212 C 6803-8 .12uF C113 C213 C 6802-0 .47uF C114 C214 C 8026-4 100uF 35V C115 C215 C 8026-4 100uF 35V C116 C216 C 6802-0 .47uF C117 C217 C 6803-8 .12uF C118 C218 C 6814-5 12pF C122 C222 C 6811-1 100pF C123 C223 C 6812-9 47pF C124 C224 C 6812-9 47pF C125 C225 C 8026-4 100uF 35V C127 C227 C 8026-4 100uF 35V C128 C228 C 7706-2 .1uF 100V C129 C229 OPEN C130 C230 C 6813-7 27pF C133 C233 C 6814-5 12pF C134 C234 C 6805-3 .022uF C135 C235 C 6805-3 .022uF C136 C236 C 6808-7 470pF C137 C237 C 6808-7 470pF C138 C238 C 6814-5 12pF C139 C239 C 6814-5 12pF C140 C240 C 6812-9 47pF C141 C241 C 6812-9 47pF C144 C244 C 8026-4 100uF 35V C145 C245 C 6814-5 12pF C146 C246 C 6809-5 220pF C147 C247 C 6806-1 .01uF C148 C248 C 6810-3 180pF C 149 C249 C 6808-7 470pF C150 C250 OPEN C151 C251 OPEN C152 C252 C 6809-5 220pF C153 C253 C 6804-6 .1uF

DIODES

D1 C 2851-1 1N4004 D2 C 2851-1 1N4004 D3 C 2851-1 1N4004 D4 C 2851-1 1N4004 D5 C 2851-1 1N4004 D6 C 2851-1 1N4004 D7 C 2851-1 1N4004 D8 C 3181-2 1N4148 D9 C 3549-0 1N916B 10V D104 D204 C 2851-1 1N4004 D105 D205 C 2851-1 1N4004 D106 D206 C 2851-1 1N4004 D107 D207 C 2851-1 1N4004 D108 D208 C 3181-2 1N4148 D109 D209 C 3181-2 1N4148 D110 D210 C 3181-2 1N4148 D111 D211 C 5061-4 1N3070 D112 D212 C 3181-2 1N4148 D113 D213 C 3181-2 1N4148 D114 D214 C 3181-2 1N4148 D115 D215 C 3181-2 1N4148 D120 D220 C 3181-2 1N4148 D121 D221 C 3181-2 1N4148 D122 D222 C 3181-2 1N4148 D123 D223 C 5061-4 1N3070 D124 D224 C 5061-4 1N3070

NETWORK RESISTORS

N100 N200 D 4669-4 Balanced Input Trim N101 N201 D 6081-0 Resistor Network-B N102 N202 D 6082-8 Resistor Network-C

TRANSISTORS

Q1 C 7458-0 2N4123 Q2 C 3625-8 2N4125 Q100 Q200 D 2961-7 SEL 2N3859A Q101 Q201 C 3578-9 MPSA93 Q102 Q202 C 3810-6 MPSA43/A42 Q103 Q203 C 3786-8 PN4250A Q104 Q204 C 3625-8 2N4125 Q105 Q205 C 3578-9 MPSA93 Q106 Q206 C 3625-8 2N4125 Q107 Q207 C 3786-8 PN4250A Q108 Q208 D 2961-7 SEL 2N3859A Q109 Q209 D 2961-7 SEL 2N3859A Q110 Q210 C 3810-6 MPSA43/A42 Q111 Q211 D 2961-7 SEL 2N3859A Q112 Q212 C 3625-8 2N4125 Q113 Q213 C 3625-8 2N4125 Q115 Q215 D 2962-5 MPS8097

Page 31

Power Base-1 & 460CSL Amplifier Service Manual

Q42776-7 Main Module Parts List (D 7251-8 Board)

Q116 Q216 C 3786-8 PN4250A Q117 Q217 D 2961-7 SEL 2N3859A Q118 Q218 D 2961-7 SEL 2N3859A Q119 Q219 C 3625-8 2N4125 Q120 Q220 C 3625-8 2N4125 Q121 Q221 C 7458-0 2N4123 Q122 Q222 C 7458-0 2N4123

RESISTORS

R1 A10265-53621 53.6K R2 A10266-2402 24 OHM R3 A10266-2402 24 OHM R4 A10265-46421 46.4K R5 A10266-3321 3.3K R11 A10266-5621 5.6K R12 A10266-4331 43K R13 A10266-1021 1K R14 A10266-8221 8.2K R15 A10266-6211 620 OHM R100 R200 OPEN R101 R201 A10265-49911 4.99K R102 R202 A10266-1021 1K R103 R203 A10266-1041 100K R104 R204 A10266-2721 2.7K R105 R205 A10266-2721 2.7K R106 R206 A10266-1231 12K R107 R207 A10266-6831 68K R108 R208 A10266-1021 1K R109 R209 A10266-8201 82 OHM R110 R210 A10266-6831 68K R111 R211 A10266-1231 12K R112 R212 A10266-5131 51K R113 R213 A10266-4721 4.7K R114 R214 A10266-4721 4.7K R115 R215 A10266-5141 510K R116 R216 A10266-3351 3.3M R117 R217 A10266-4731 47K R118 R218 A10266-2711 270 OHM R119 R219 A10266-3011 300 OHM R120 R220 A10266-2711 270 OHM R121 R221 C 5062-2 100K TRIMMER R122 R222 A10266-2741 270K R123 R223 A10266-1831 18K R124 R224 A10266-6821 6.8K R125 R225 C 7782-3 100 OHM R126 R226 C 7782-3 100 OHM R127 R227 A10266-6821 6.8K R128 R228 A10266-1031 10K R129 R229 A10266-1041 100K R130 R230 A10266-1041 100K R131 R231 A10266-1031 10K R132 R232 C 5062-2 100K TRIMMER

R133 R233 A10266-2741 270K R134 R234 A10266-1831 18K R135 R235 C 7782-3 100 OHM R136 R236 A10266-6821 6.8K R137 R237 C 7782-3 100 OHM R138 R238 A10266-6821 6.8K R139 R239 A10266-1021 1K R140 R240 A10266-8201 82 OHM R141 R241 A10266-1541 150K R142 R242 A10266-1541 150K R146 R246 A10266-1031 10K R147 R247 C 7781-5 200 OHM R148 R248 A10266-2721 2.7K R149 R249 C 7781-5 200 OHM R150 R250 A10266-2721 2.7K R151 R251 A10266-1031 10K R152 R252 A10266-1231 12K R153 R253 C 5868-2 ZERO OHM R156 R256 A10266-1321 1.3K R157 R257 A10266-1321 1.3K R158 R258 A10266-9121 9.1K R159 R259 A10266-1031 10K R161 R261 A10266-4701 47 OHM R162 R262 A10266-4701 47 OHM R167 R267 A10266-1021 1K R168 R268 A10265-95301 953 OHM R170 R270 A10266-1021 1K R171 R271 A10265-95301 953 OHM R174 R274 A10265-24921 24.9K R175 R275 A10265-14721 14.7K R176 R276 A10265-24921 24.9K R179 R279 A10266-4731 47K R180 R280 A10266-4711 470 OHM R181 R281 A10266-4721 4.7K R182 R282 A10266-2201 22 OHM R183 R283 A10266-2421 2.4K R185 R285 A10266-2421 2.4K R186 R286 A10266-1051 1M R187 R287 A10265-52321 52.3K

SWITCHES

S2 C 7325-1 DPDT SIDE S3 C 7363-2 DPDT GOLD S100 C 6781-6 6P3T

IC’S

U1 C 5095-2 MC7815 U2 C 5096-0 MC7915 U100 U200 C 6911-9 UPA75 PNP U103 U203 C 6910-1 UPA76 NPN U104 U204 C 6900-2 MC34084P

Page 32

Power Base-1 & 460CSL Amplifier Service Manual

Q42776-7 Main Module Parts List (D 7251-8 Board)

INTERCONNECTS

J1 C 7593-4 HEADER 5 PIN J2 C 4508-5 16 PIN SOCKET J9 C 7527-2 HEADER 6 PIN J10 C 7592-6 HEADER 4 PIN J11 C 7526-4 HEADER 3 PIN J100 J200 C 6777-4 PHONE JACK J500 J800 D 6619-7 10" RIBBON ASSY J600 J700 D 6620-5 6" RIBBON ASSY

MISC.

BOARD D 7251-8 MOUNTS U1, U2:

(2) C 1889-2 6-32 NUT (2) C 2176-3 6-32 X .5 SCREW (2) C 5341-0 HEATSINK (2) C 5594-4 STAR WASHER

MOUNTS U104, U204:

(2) C 3450-1 14 PIN SOCKET

COVERS FOR J100, J200:

(2) C 6778-2 Phone Jack Cover

STRAIN RELIEF:

(4) C 1811-6 CABLE TIE

Note: To use this module in the PB-1, it is necessary to remove R187/287 and install level control pots (C 7409-3).

Page 33

Power Base-1 & 460CSL Amplifier Service Manual

Q42953-2 Main Module Parts List (D 7251-8 Board)

Q42953-2 PB-1 Main Module 3rd Gain Stage and Improved offset (Original 460CSL Main Module.):

CAPACITORS

C1 C 3913-8 470µF C2 C 3913-8 470µF C4 C 6802-0 .47µF C5 C 6806-1 .01µF C6 C 6806-1 .01µF C7 C 6094-4 33µF 16V C8 C 6806-1 .01µF C100 C200 C 5311-3 22µF C101 C201 C 2820-6 5pF C103 C203 C 6805-3 .022µF C104 C204 C 6804-6 .1µF C105 C205 C 6812-9 47pF C106 C206 C 6812-9 47pF C108 C208 C 6814-5 12pF C112 C212 C 6803-8 .12µF C113 C213 C 6802-0 .47µF C114 C214 C 8876-8 100µF 35V C115 C215 C 8876-8 100µF 35V C116 C216 C 6802-0 .47µF C117 C217 C 6803-8 .12µF C118 C218 C 6814-5 12pF C122 C222 C 6811-1 100pF C123 C223 C 6811-1 100pF C124 C224 C 6812-9 47pF C127 C227 C 8576-8 100pF C128 C228 C 7706-2 .1µF C130 C230 C 6813-7 27pF C133 C233 C 6814-5 12pF C134 C234 C 6805-3 .022µF C135 C235 C 6805-3 .022µF C136 C236 C 6808-7 470pF C137 C237 C 6808-7 470pF C138 C238 C 6814-5 12pF C139 C239 C 6814-5 12pF C140 C240 C 6812-9 47pF C141 C241 C 6812-9 47pF C144 C244 C 8576-8 100µF 35V C145 C245 C 6814-5 12pF C146 C246 C 6809-5 220pF C147 C247 C 6806-1 .01µF C148 C248 C 6810-3 180pF C149 C249 C 6808-7 470pF C152 C252 C 6809-5 220pF C153 C253 C 6804-6 .1µF

DIODES

D1 C 2851-1 1N4004

D2 C 2851-1 1N4004 D3 C 2851-1 1N4004 D4 C 2851-1 1N4004 D5 C 2851-1 1N4004 D6 C 2851-1 1N4004 D7 C 2851-1 1N4004 D8 C 3181-2 1N4148 D9 C 3549-0 1N916B 10V Zener D104 D204 C 2851-1 1N4004 D105 D205 C 2851-1 1N4004 D106 D206 C 2851-1 1N4004 D107 D207 C 2851-1 1N4004 D108 D208 C 3181-2 1N4148 D109 D209 C 3181-2 1N4148 D110 D210 C 3181-2 1N4148 D111 D211 C 5061-4 1N3070 D112 D212 C 3181-2 1N4148 D113 D213 C 3181-2 1N4148 D114 D214 C 3181-2 1N4148 D115 D215 C 3181-2 1N4148 D120 D220 C 3181-2 1N4148 D121 D221 C 3181-2 1N4148 D122 D222 C 3181-2 1N4148 D123 D223 C 5061-4 1N3070 D124 D224 C 5061-4 1N3070

TRANSISTORS

Q1 C 7458-0 NPN 2N4123 Q2 C 3625-8 PNP 2N4125 Q100 Q200 D 2961-7 NPN 2N3859A SEL Q101 Q201 C 3578-9 PNP MPSA93 Q102 Q202 C 3810-6 NPN MPSA43/A42 Q103 Q203 C 3786-8 PNP PN4250A Q104 Q204 H43113-2 Diode Pair Q105 Q205 C 3578-9 PNP MPSA93 Q106 Q206 C 3625-8 PNP 2N4125 Q107 Q207 C 3786-8 PNP PN4250A Q108 Q208 D 2961-7 NPN 2N3859A SEL Q109 Q209 D 2961-7 NPN 2N3859A SEL Q110 Q210 C 3810-6 NPN MPSA43/A42 Q111 Q211 H43113-2 Diode Pair Q112 Q212 C 3625-8 PNP 2N4125 Q113 Q213 C 3625-8 PNP 2N4125 Q115 Q215 D 2962-5 NPN MPS8097 Q116 Q216 C 3786-8 PNP PN4250A Q117 Q217 D 2961-7 NPN 2N3859A SEL Q118 Q218 D 2961-7 NPN 2N3859A SEL Q119 Q219 C 3625-8 PNP 2N4125 Q120 Q220 C 3625-8 PNP 2N4125 Q121 Q221 C 7458-0 NPN 2N4123 Q122 Q222 C 7458-0 NPN 2N4123

Page 34

Power Base-1 & 460CSL Amplifier Service Manual

Q42953-2 Main Module Parts List (D 7251-8 Board)

RESISTORS

N100 N200 D 4669-4 CMR Trim Network N101 N201 D 6081-0 Resistor Network N102 N202 D 6082-8 Resistor Network R1 A10265-53621 53.6K 1% R2 C 7340-0 24 5W R3 C 7340-0 24 5W R4 A10265-46421 46.4K 1% R5 A10266-3321 3.3K R11 A10266-5621 5.6K R12 A10266-4331 43K R13 A10266-1021 1K R14 A10266-8221 8.2K R15 A10266-6211 620 R100 R200 C 7409-3 Pot, 5K Linear R101 R201 A10265-49911 4.99K 1% R102 R202 A10266-1021 1K R103 R203 A10265-10031 100K 1% R104 R204 A10266-2721 2.7K R105 R205 A10266-2721 2.7K R106 R206 A10266-1231 12K R107 R207 A10266-6831 68K R108 R208 A10266-1021 1K R109 R209 A10266-8201 82 R110 R210 A10266-6831 68K R111 R211 A10266-1231 12K R112 R212 A10266-5131 51K R113 R213 A10266-4721 4.7K R114 R214 A10266-4721 4.7K R115 R215 A10266-5141 510K R116 R216 A10266-3351 3.3M R117 R217 A10266-4731 47K R118 R218 C 7780-7 270 Flame Proof R119 R219 A10266-3011 300 R120 R220 C 7780-7 270 Flame Proof R121 R221 C 5062-2 100K Pot (–ODEP) R122 R222 A10266-2741 270K R123 R223 A10266-1832 18K .5W R124 R224 A10266-6821 6.8K R125 R225 A10266-1011 100 R126 R226 A10266-1011 100 R127 R227 A10266-6821 6.8K R128 R228 A10266-1031 10K R129 R229 A10266-1041 100K R130 R230 A10266-1041 100K R131 R231 A10266-1031 10K R132 R232 C 5062-2 100K Pot (+ODEP) R133 R233 A10266-2741 270K R134 R234 A10266-1832 18K .5W

R135 R235 A10266-1011 100 R136 R236 A10266-6821 6.8K R137 R237 A10266-1011 100 R138 R238 A10266-6821 6.8K R139 R239 A10266-1021 1K R140 R240 A10266-8201 82 R141 R241 A10266-1541 150K R142 R242 A10266-1541 150K R146 R246 A10266-1031 10K R147 R247 C 7781-5 200 .5W Flame Proof R148 R248 A10266-2721 2.7K R149 R249 C 7781-5 200 .5W Flame Proof R150 R250 A10266-2721 2.7K R151 R251 A10266-1031 10K R152 R252 A10266-1231 12K R153 R253 C 5868-2 0 Ohm Jumper R156 R256 A10266-1321 1.3K R157 R257 A10266-1321 1.3K R158 R258 A10266-9131 9.1K R159 R259 A10266-5121 5.1K R161 R261 A10266-1011 100 R162 R262 A10266-1011 100 R167 R267 A10265-10011 1K 1% R168 R268 A10265-95301 953 1% R170 R270 A10265-10011 1K 1% R171 R271 A10265-95301 953 1% R174 R274 A10265-24921 24.9K 1% R175 R275 A10265-14721 14.7K 1% R176 R276 A10265-24921 24.9K 1% R179 R279 A10266-4731 47K R180 R280 A10266-4711 470 R181 R281 A10266-4721 4.7K R182 R282 A10266-2201 22 R183 R283 A10266-2421 2.4K R185 R285 A10266-2421 2.4K R186 R286 A10266-1051 1M

SWITCHES

S2 C 7325-1 Ground Switch S3 C 7363-2 Sensitivity S100 C 6781-6 Stereo/Mono

IC’S

U1 C 5095-2 UA7815 U2 C 5096-0 UA7915 U100 U200 C 6911-9 UPA75 U103 U203 C 6910-1 UPA76 U104 U204 C 6900-2 MC33084P

Page 35

Power Base-1 & 460CSL Amplifier Service Manual

Q42953-2 Main Module Parts List (D 7251-8 Board)

MISC.

Board D 7251-8 Blank PC Board Socket C 3450-1 14 Pin U104/204 Nut A10102-5 Hex 6-32 Heatsink C 5341-0 TO-220 Torq Sprdr C 6541-4 Washer C 8973-7 #6, Split Screw C 9067-7 Stainless J1 C 7593-4 5 Pin Header J2 C 4508-5 16 Pin Socket J9 C 7527-2 6 Pin Header J10 C 7592-6 4 Pin Header J11 C 7526-4 3 Pin Header J100 J200 C 6777-4 Phone Jack Cover C 6778-2 Phone Jack Cover J500 J800 D 6619-7 10 Inch Ribbon J600 J700 D 6620-5 6 Inch Ribbon

Page 36

Power Base-1 & 460CSL Amplifier Service Manual

Q43060-5 Main Module Parts List (D 7993-5 Board)

Q43060-5 Applicability: Main Module for Through Hole Chassis (THC) PB-1/460CSL units.

CAPACITORS

C1 C 4303-1 1000µF C2 C 3913-8 470µF C4 C 6802-0 .47µF C5 C 6806-1 .01µF C6 C 6806-1 .01µF C7 C 8897-8 .1µF C100 C200 C 5311-3 22µF C101 C201 C 2821-4 10pF C103 C203 C 6805-3 .022µF C104 C204 C 6805-3 .022µF C105 C205 C 6812-9 47pF C106 C206 C 6812-9 47pF C107 C207 C 8897-8 .1µF C108 C208 C 6814-5 12pF C109 C209 C 7417-6 .0033µF C110 C210 C 5362-6 2.2µF C111 C211 C 8897-8 .1µF C112 C212 C 6803-8 .12µF C113 C213 C 8991-9 .47µF C114 C214 C 8854-9 100µF C115 C215 C 8854-9 100µF C116 C216 C 8991-9 .47µF C117 C217 C 6803-8 .12µF C118 C218 C 6814-5 12pF C119 C219 C 6802-0 .47µF C120 C220 C 8897-8 .1µF C122 C222 C 6811-1 100pF C123 C223 C 6812-9 47pF C124 C224 C 6812-9 47pF C129 C229 C 6814-5 12pF C130 C230 C 6813-7 27pF C133 C233 C 6813-7 27pF C134 C234 C 6805-3 .022µF C135 C235 C 6805-3 .022µF C136 C236 C 6808-7 470pF C137 C237 C 6808-7 470pF C138 C238 C 6813-7 27pF C139 C239 C 6813-7 27pF C140 C240 C 6812-9 47pF C141 C241 C 6812-9 47pF C144 C244 C 8576-8 100µF C145 C245 C 6812-9 47pF C146 C246 C 6812-9 47pF C147 C247 C 6806-1 .01µF C148 C248 C 6810-3 180pF C149 C249 C 6808-7 470pF C150 C250 C 6806-1 .01µF

C151 C251 C 6806-1 .01µF C152 C252 C 6950-7 82pF 5% C153 C253 C 8897-8 .1µF C154 C254 C 8426-6 .1µF 250V C155 C255 C 8897-8 .1µF C156 C256 C 8897-8 .1µF C157 C257 C 6806-1 .01µF

DIODES

D1 C 2851-1 1N4004 D2 C 2851-1 1N4004 D3 C 2851-1 1N4004 D4 C 2851-1 1N4004 D5 C 2851-1 1N4004 D6 C 2851-1 1N4004 D7 C 2851-1 1N4004 D108 D208 C 3181-2 1N4148 D109 D209 C 3181-2 1N4148 D110 D210 C 3181-2 1N4148 D111 D211 C 5061-4 1N3070 D112 D212 C 3181-2 1N4148 D113 D213 C 3181-2 1N4148 D120 D220 C 3181-2 1N4148 D121 D221 C 3181-2 1N4148 D122 D222 C 3181-2 1N4148 D123 D223 C 5061-4 1N3070 D124 D224 C 3181-2 1N4148 D125 D225 C 3181-2 1N4148 D126 D226 C 5061-4 1N3070 D127 D227 C 5061-4 1N3070 D129 D229 C 3181-2 1N4148 D130 D230 C 3181-2 1N4148 D131 D231 C 3181-2 1N4148 D132 D232 C 3181-2 1N4148

TRANSISTORS

Q100 Q200 D 2961-7 NPN 2N3859A Q101 Q201 C 3578-9 PNP MPSA93 Q102 Q202 C 3810-6 NPN MPSA43 Q103 Q203 C 3786-8 PNP PN4250 Q105 Q205 C 3578-9 PNP MPSA93 Q106 Q206 C 3625-8 NPN 2N4125 Q107 Q207 C 3786-8 PNP PN4250 Q108 Q208 D 2961-7 NPN 2N3859A Q109 Q209 D 2961-7 NPN 2N3859A Q110 Q210 C 3810-6 NPN MPSA43 Q112 Q212 C 3625-8 NPN 2N4125 Q113 Q213 C 3625-8 NPN 2N4125 Q115 Q215 D 2962-5 NPN MPS8097 Q116 Q216 C 3786-8 PNP PN4250 Q117 Q217 D 2961-7 NPN 2N3859A Q118 Q218 D 2961-7 NPN 2N3859A

Page 37

Power Base-1 & 460CSL Amplifier Service Manual

Q43060-5 Main Module Parts List (D 7993-5 Board)

Q119 Q219 C 3625-8 NPN 2N4125 Q120 Q220 C 3625-8 NPN 2N4125 Q121 Q221 C 7458-0 NPN 2N4123 Q122 Q222 C 7458-0 NPN 2N4123 Q123 Q223 C 7458-0 NPN 2N4123 Q124 Q224 C 3625-8 NPN 2N4125

RESISTORS

N101 N201 D 6081-0 Network Package N102 N202 D 6082-8 Network Package R1 A10265-53621 53.6K 1% R2 C 7340-0 24 5W R3 C 7340-0 24 5W R4 A10265-46421 46.4K 1% R5 A10266-3321 3.3K R7 A10266-1041 100K R8 A10266-2031 20K R9 A10266-5121 5.1K R16 A10266-5121 5.1K R17 A10266-2031 20K R18 A10266-1041 100K R100 R200 C 7409-3 5K Linear Pot (Level) R101 R201 A10265-49911 4.99K 1% R102 R202 A10266-5111 510 R103 R203 A10265-10031 100K 1% R104 R204 A10266-2721 2.7K R105 R205 A10266-2721 2.7K R106 R206 A10266-1231 12K R107 R207 A10266-6831 68K R108 R208 A10266-8211 820 R109 R209 A10266-6801 68 R110 R210 A10266-6831 68K R111 R211 A10266-1231 12K R113 R213 A10266-4721 4.7K R118 R218 C 7780-7 270 Flame Proof R119 R219 A10266-3011 300 R120 R220 C 7780-7 270 Flame Proof R121 R221 C 5062-2 100K Pot (-ODEP) R122 R222 A10266-2741 270K R123 R223 A10266-1832 18K .5W R124 R224 A10266-6821 6.8K R125 R225 C 7782-3 100 Flame Proof R126 R226 C 7782-3 100 Flame Proof R127 R227 A10266-6821 6.8K R128 R228 A10266-1031 10K R129 R229 A10266-1041 100K R130 R230 A10266-1041 100K R131 R231 A10266-1031 10K R132 R232 C 5062-2 100K Pot (+ODEP) R133 R233 A10266-2741 270K R134 R234 A10266-1832 18K .5W R135 R235 C 7782-3 100 Flame Proof

R136 R236 A10266-6821 6.8K R137 R237 C 7782-3 100 Flame Proof R138 R238 A10266-6821 6.8K R139 R239 A10266-8211 820 R140 R240 A10266-6801 68 R141 R241 A10266-1541 150K R142 R242 A10266-1541 150K R143 R243 A10266-1041 100K R144 R244 A10266-1041 100K R145 R245 A10266-1851 1.8M R146 R246 A10266-1031 10K R147 R247 C 7781-5 200 .5W Flame Proof R148 R248 A10266-2721 2.7K R149 R249 C 7781-5 200 .5W Flame Proof R150 R250 A10266-2721 2.7K R151 R251 A10266-1031 10K R152 R252 A10266-1231 12K R153 R253 JUMPER JUMPER R154 R254 C 8261-7 121K 0.1% R155 R255 A10266-1321 1.3K R156 R256 A10266-1321 1.3K R157 R257 A10266-1321 1.3K R158 R258 A10266-9121 9.1K R159 R259 A10266-1021 1K R160 R260 C 8260-9 10K 0.1% R161 R261 A10266-1011 100 R162 R262 A10266-1011 100 R163 R263 C 8261-7 121K 0.1% R164 R264 C 8260-9 10K 0.1% R165 R265 C 8261-7 121K 0.1% R166 R266 A10266-1851 1.8M R167 R267 A10265-10011 1K 1% R168 R268 A10265-95301 953 1% R170 R270 A10265-10011 1K 1% R171 R271 A10265-95301 953 1% R173 R273 C 8260-9 10K 0.1% R174 R274 A10265-24921 24.9K 1% R175 R275 A10265-14721 14.7K 1% R176 R276 A10265-24921 24.9K 1% R177 R277 A10265-54921 54.9K 1% R179 R279 A10266-1321 1.3K R180 R280 A10266-4711 470 R181 R281 A10266-4721 4.7K R182 R282 A10266-2201 22 R183 R283 A10266-2421 2.4K R184 R284 A10266-4741 470K R185 R285 A10266-2421 2.4K R186 R286 A10266-2751 2.7M R187 R287 A10266-3631 36K R188 R288 A10266-3631 36K R189 R289 A10266-2731 27K R190 R290 A10266-2051 2M

Page 38

Power Base-1 & 460CSL Amplifier Service Manual

Q43060-5 Main Module Parts List (D 7993-5 Board)

R191 R291 A10266-3331 33K R192 R292 A10266-1031 10K R193 R293 A10266-1031 10K R194 R294 A10266-1041 100K R195 R295 A10266-3021 3K R196 R296 A10266-4721 4.7K R197 R297 A10266-1031 10K R198 R298 A10266-4721 4.7K R199 R299 A10266-1031 10K R909 R1009 A10266-4741 470K R910 R1010 A10266-4741 470K R911 R1011 A10266-1521 1.5K R912 R1012 A10266-4711 470 R913 R1013 A10266-1051 1M R915 R1015 A10266-1001 10 R916 R1016 A10266-1001 10 R917 R1017 A10266-10021 10K R918 R1018 A10266-10021 10K R919 R1019 A10266-10021 10K R920 R1020 A10266-10021 10K R921 R1021 C 9079-2 200 Pot (CMR Null)

SWITCHES

S2 C 7325-1 Ground Lift S3 C 7960-5 Sensitivity S4 C 6781-6 Stereo/Mono

IC’S

U1 C 5095-2 UA7815 U2 C 5096-0 UA7915 U100 U200 C 6911-9 UPA75 U101 U201 C 4345-2 LM339 U102 U202 C 4345-2 LM339 U103 U203 C 6910-1 UPA76 U104 U204 C 7558-7 MC33079P

MISC.

Board D 7993-5 Socket C 3450-1 14 Pin Nut A10102-5 Hex 6-32 Heatsink C 5341-0 TO-220 Torq. Spreader C 6541-4 Washer C 8973-7 #6, Split Screw C 9067-7 Stainless J1 C 7593-4 5 Pin Header J11 C 7526-4 3 Pin Header J12 C 7873-0 2 Pin Header J100 J200 C 6777-4 Phone Jack Cover C 6778-2 Phone Jack Cover J500 J800 D 6619-7 10 Inch Ribbon J600 J700 D 6620-5 6 Inch Ribbon

Page 39

™

POWER

OFF

POWER

OFF

E106377

Applies only to 120 VAC,

North American PB-1,

PB-2 and PB-3 units.

OFF

Models:

Power Base-1, 2 & 3

© 1996 by Crown International, Inc., P.O. Box 1000, Elkhart, Indiana 46515-1000 U.S.A. Telephone: 219-294-8000. Power-Tech amplifiers are produced by the Professional Audio Division of Crown International, Inc. Trademark Notice: and

Power Base-1®, Power Base-2®, Crown

Power Base-3

registered trademarks of Crown International, Inc. Other trademarks are the property of their respective owners.

™

is a trademark

,®

IOC

and

ODEP

are

POWER

LL 32521C

Applies only to 120 VAC,

North American PB-1

and PB-2 units.

101229-1

12/96

Page 40

Power Base Series Power Amplifiers

CONTENTS

1 Welcome .......................................................................... 7

1.1 Unpacking ................................................................. 7

1.2 Features .................................................................... 7

2 Installation ....................................................................... 9

2.1 Stereo ........................................................................ 9

2.2 Mono ......................................................................... 9

2.3 Input Sensitivity Adjustment...................................... 10

2.4 Additional Load Protection ....................................... 10

2.5 Required AC Mains .................................................. 10

3 Operation ....................................................................... 11

3.1 Precautions .............................................................. 11

3.2 Power Indicator ........................................................ 11

3.3 Protection Systems................................................... 11

3.3.1

ODEP ............................................................

3.3.2 Ultrasonic and RF Protection .......................... 11

3.3.3 Drive Protection ............................................. 11

3.3.4 Transformer Thermal Protection ..................... 12

3.3.5 Fuses and Circuit Breakers ............................ 12

3.4 Controls ................................................................... 12

3.5 Filter Cleaning .......................................................... 12

4 Specifications................................................................ 13

5 Accessories ................................................................... 19

5.1 MT-XLR .................................................................... 19

5.2 MT-BB ..................................................................... 19

6 Service ........................................................................... 20

6.1 Worldwide Service ................................................... 20

6.2 North American Service ........................................... 20

6.2.1 Service at a North American Service Center ... 20

6.2.2 Factory Service .............................................. 20

Page 4

Page 41

Power Base Series Power Amplifiers

1.1 Power Base Front and Back Panels .................................... 7

2.1Three System Connection Methods ....................................... 8

2.2Do NOT Block Air Flow .......................................................... 9

2.3Power Base Input Wiring ....................................................... 9

2.4Input Sensitivity Switch ........................................................ 10

2.5Loudspeaker Fuse Nomograph ........................................... 10

3.1Back Panel Level Controls ................................................... 12

4.1Power Base-1 Minimum Power Matrix .................................. 15

4.2Power Base-2 Minimum Power Matrix .................................. 16

4.3Power Base-3 Minimum Power Matrix .................................. 16

4.4Power Base-1 Maximum Power Matrix ................................. 17

4.5Power Base-2 Maximum Power Matrix ................................. 18

4.6Power Base-3 Maximum Power Matrix ................................. 18

5.1The MT-XLR ........................................................................ 19

5.2The MT-BB .......................................................................... 19

ILLUSTRATIONS

Page 5

Page 42

Power Base Series Power Amplifiers

Page 6

Page 43

Power Base Series Power Amplifiers

Power

Indicator

Power

Switch

POWER

OFF

Access

Cover

CAUTION: THIS COVER IS NECESSARY FOR EFFICIENT COOLING OF THE AMPLIFIER. REMOVE ONLY TO ACCESS GAIN SWITCH.

THIS AMPLIFIER IS EQUIPPED WITH SELECTABLE INPUT SENSITIVITY. REMOVE COVER PLATE (ABOVE) TO ACCESS SENSITIVITY SWITCH.

CH-2

567

8 9

BALANCED

INPUT WIRING

MONO

TIP

INPUT

RING

–

GAIN

SLEEVE

GND

Ch.2

¼ Inch

Level

Phone

Control

Input

(Power Base–3 Only)

MODEL: POWER-BASE™ 3 12.5 AMPS AC VOLTS: 120 60 Hz

MAXIMUM OUTPUT: 700 WATTS PER CHANNEL INTO 4 OHMS AT 1 KHz WITH NO MORE THAN 0.1% THD.

INTERNATIONAL, INC.

ELECTRONIC EQUIPMENT

ELKHART, IN 46517 MADE IN U.S.A.

000000

SERIAL NUMBER

WARNING:

TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK, DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE.

REG. U.S. PAT. OFF.

4,330,809 4,611,180

0000

Reset

Switch

PUSH TO RESET

PARALLEL

MONO

CAUTION:

TURN OFF AMPLIFIER

BEFORE CHANGING THIS SWITCH!

Stereo/Mono

Switch

Power

Cord

STEREO

BRIDGE

Fig. 1.1 Power Base Front and Back Panels

1 Welcome

Congratulations on choosing a

Power Base

amplifiers are compact, professional stereo power amplifiers engineered to meet the most demanding sound reinforcement needs. They compare very favorably to more expensive amplifiers, providing uncolored sound and signal-to-noise ratios commonly associated with recording studios.

This manual will help you successfully install and use your amplifier—we strongly recommend you read all instructions, warnings and cautions. If you plan to operate in one of the two mono modes, be sure to read Section 2.2. Also for your protection, please save your bill of sale as it is your official proof of purchase.

1.1 Unpacking

Please unpack and inspect your new amplifier for any damage that may have occurred during transit. If damage is found, notify the transportation company immediately. Only you, the consignee, may initiate a claim with the carrier for damage resulting during shipment. Even if the unit arrived in perfect condition, as most do, save all packing materials so you will have them if you ever need to transport the unit. NEVER SHIP THE

UNIT WITHOUT THE FACTORY PACK.

Power Base

amplifier.

Removable grille

and dust filter

INPUT GROUND LIFT

LIFT

(AFFECTS PHONE INPUTS ONLY.)

Ground

Lift

Switch

INPUT

(MONO)

Ch.1 ¼ Inch Phone

CH-1

567

4 3 2

GAIN

Ch.1

Level

Control

UNBALANCED

INPUT WIRING

GND

5-Way Binding Post

Output Connectors

OUTPUTS

CLASS 2

OUTPUT WIRING

REQUIRED.

BRIDGE-MONO WIRING

TURN AMPLIFIER OFF.

SET STEREO/MONO SWITCH TO BRIDGE-MONO.

OUTPUT ACROSS RED TERMINALS

TIP

ONLY. (CH-1 IS POSITIVE.)

SLEEVE

CH-2 CH-1

–

CAUTION:

SHOCK DO NOT REMOVE TOP OR BOTTOM COVERS. NO USER SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED SERVICE PERSONNEL. DISCONNECT POWER CORD BEFORE REMOVING REAR COVER PLATE TO ACCESS SENSITIVITY SWITCH.

ATTENTION:

D'OUVRIR.

PARALLEL-MONO WIRING

TURN AMPLIFIER OFF.

SET STEREO/MONO SWITCH TO PARALLEL-MONO.

ADD JUMPER (14 GAGE OR LARGER) ACROSS RED TERMINALS.

OUTPUT ACROSS CH-1 TERMINALS ONLY.

TO PREVENT ELECTRIC

DÉBRANCHER AVANT

–

1.2 Features

❏ Rugged, professional power amplifier built for the road.

Mounts in a standard 19 inch (48.3 cm) rack.

❏ Crown’s patented

grounded bridge

ates large voltage swings while avoiding electrical stress on the output stages. This results in low distortion and high reliability.

❏ Front panel power switch with turn-on delay for loud-

speaker protection.

❏ Patented Output Device Emulation Protection (

keeps the amplifier working when others would fail.

❏ High damping factor provides superior control over low

frequency drivers for a clean, accurate low end.

❏ Safe with any load. Bridge-Mono and Parallel-Mono

modes offer optimal load-matching performance.

❏ Complete protection against shorted outputs, mis-

matched loads, overheating, DC input/output and highfrequency overload; full internal fault protection.

❏ Balanced phone jack inputs with internal three-position

sensitivity switch. Optional XLR or barrier block input connectors are available with the cessories.

❏ Ground lift switch is provided to isolate the chassis

ground from the phone jack input ground.

❏ Efficient heat sinks and self-contained forced air cool-

ing system dissipate heat quickly and evenly for extra amplifier protection and greater power output.

❏ Three year “No-Fault” full warranty and guaranteed

specifications protect your investment.

circuitry gener-

MT-XLR

ODEP

MT-BB

ac-

)

Page 7

Page 44

Power Base Series Power Amplifiers

CHANNEL 2

MIXER

STEREO MODE

MIXER

BRIDGE-MONO MODE

POWER BASE AMPLIFIER

PARALLEL

MONO

CAUTION:

BEFORE CHANGING THIS SWITCH.

ONLY USE THE CHANNEL 1 INPUT

POWER BASE AMPLIFIER

PARALLEL

MONO

CAUTION:

BEFORE CHANGING THIS SWITCH.

CHANNEL 1

CHANNEL 2

STEREO

BRIDGE

PARALLEL

MONO

STEREO

TURN OFF AMPLIFIER

STEREO

BRIDGE

PARALLEL

MONO

STEREO

TURN OFF AMPLIFIER

BRIDGE

MONO

CHANNEL 2 IS

NOT USED IN

THIS MODE.

BRIDGE

MONO

CH-2 CH-1

CH.2

GROUND

LEVEL

CONTROL

CH-2 CH-1

LIFT

SWITCH

TURN CHANNEL 2

OFF (FULLY CCW)

IN THIS MODE.

CH.1

LEVEL

CONTROL

DO NOT

USE BLACK

TERMINALS

–

LOUDSPEAKERS

–

CHANNEL 1

–

LOUDSPEAKER

MIXER

PARALLEL-MONO MODE

Page 8

ONLY USE THE CHANNEL 1 INPUT

POWER BASE AMPLIFIER

PARALLEL

MONO

CAUTION:

BEFORE CHANGING THIS SWITCH.

Fig. 2.1 Three System Connection Methods

STEREO

BRIDGE

PARALLEL

MONO

STEREO

TURN OFF AMPLIFIER

CHANNEL 2 IS

NOT USED IN

THIS MODE.

BRIDGE

MONO

CH-2 CH-1

ADD A 14 GAUGE

(OR LARGER)

JUMPER BETWEEN

THE RED CHANNEL 1

AND CHANNEL 2

BINDING POSTS.

–

LOUDSPEAKER

Page 45

Power Base Series Power Amplifiers

2 Installation

Always remove power from the unit and turn the level controls off (fully counterclockwise) when making or breaking connections. This reduces the chance of blasts that can cause loudspeaker damage.

The guidelines below are provided to help you quickly get your amplifier installed and ready to go. Be sure to follow the instructions in Sections 2.1 and 2.2 for the selected mode of operation. Additional information on input sensitivity, load protection and required AC mains is provided in Sections 2.3, 2.4 and 2.5.

1. Install the amplifier in a standard 19 inch (48.3 cm) rack or place it on a stable surface. The mounting dimensions are 19 inches (48.3 cm) wide, 3.5 inches (8.9 cm) tall and 16 inches (40.6 cm) deep behind the mounting surface. IMPORTANT! Allow for adequate ventilation.

17 in

43.2 cm

IMPORTANT: Be sure the back of

the amplifier is supported.

AIR

FLOW

16 in

40.6 cm

2 in

MIN.

AMPLIFIER

(TOP VIEW)

AIR FLOW

Fig. 2.2 Do NOT Block Air Flow

2. Use high-quality loudspeaker cables to connect the load to the amplifier’s outputs. Do not use shielded cable.

3. Use shielded cables to connect audio sources to the amplifier inputs. Either balanced or unbalanced wiring can be used as shown below. (XLR connectors are available with the MT-XLR accessory. See Section 5.)

INPUT

BALANCED

GND

–

PREAMPLIFIER

–

SHIELD

FROM

UNBALANCED

INPUT

SHIELD

PREAMPLIFIER

AIR

FLOW

FROM

RACK

CABINET

2.1 Stereo

1. Turn down the level controls (fully counterclockwise) and turn off the amplifier.

2. Set the back panel stereo/mono switch to Stereo.

3. If present, remove the Parallel-Mono jumper.

4. Connect the input and output cables as shown in the first example in Figure 2.1.

5. Turn on the amplifier and adjust the level for each channel using the back panel level controls.

CAUTION: Never parallel the two outputs by directly tying them together, and never parallel them with the output of another amplifier.

2.2 Mono

Your amplifier’s mono modes provide double the power of Stereo mode in a single channel. In BridgeMono mode, the outputs are wired in series for twice the output voltage. In Parallel-Mono mode, the outputs are paralleled for twice the current capacity.

Bridge-Mono mode is provided for loads with an impedance greater than 4 ohms. Parallel-Mono mode should be used with loads of 4 ohms or less.

B R I D G E - M O N O

1. Turn down the level controls (fully counterclockwise) and turn off the amplifier.

2. Set the back panel stereo/mono switch to Bridge-Mono.

3. If present, remove the Parallel-Mono jumper.

4. Connect the input and output cables as shown in the second example in Figure 2.1. Only use the channel 1 input.

5. Make sure the load is balanced (neither side shorted to ground) and do not use the black (–) binding posts.

6. Turn on the amplifier and adjust the level. Only use the

channel 1 level control.

P A R A L L E L - M O N O

1. Turn down the level controls (fully counterclockwise) and turn off the amplifier.

2. Set the back panel stereo/mono switch to Parallel-Mono.

3. Install a solid, 14-gauge (2 mm2) or heavier jumper wire across the two red (+) binding post outputs.

4. Connect the input and output cables as shown in the third example in Figure 2.1. Only use the channel 1 input.

5. Turn on the amplifier and adjust the level. Only use the

channel 1 level control.

CAUTION: With Parallel-Mono wiring, do not switch to Stereo or Bridge-Mono mode until the output jumper wire is removed.

Fig. 2.3 Power Base Input Wiring

Page 9

Page 46

Power Base Series Power Amplifiers

2.3 Input Sensitivity Adjustment

The input sensitivity switch inside the amplifier is set to

0.775 volts at the factory. It can be changed to 1.4 volts or a voltage gain of 26 dB as follows:

1. Turn off and unplug the amplifier from the AC source.

2. Remove the access cover on the back panel.

3. Locate the labeled access hole for the sensitivity switch.

4. Set the switch to the desired position.

5. Replace the access cover plate.

CH-1

567

4 3 2

GAIN

requires a

UNBALANCED

INPUT WIRING

GND

SLEEVE

TIP

When set to 26 dB gain, the

2.0 volt input, the put and the

Power Base-2

Power Base-3

Power Base-1

requires a 2.5 volt in-

™

requires a 3.2 volt input to

deliver full output into an 8 ohm load.

SENSITIVITY SWITCH INSIDE ACCESS HOLE

1.4 V

26 dB

THIS AMPLIFIER IS EQUIPPED WITH SELECTABLE INPUT SENSITIVITY. REMOVE COVER PLATE (ABOVE) TO ACCESS SENSITIVITY SWITCH.

BALANCED

INPUT WIRING

TIP

RING

–

SLEEVE

GND

CH-2

567

GAIN

Fig. 2.4 Input Sensitivity Switch

0.77 V

INPUT

INPUT GROUND LIFT

LIFT

(AFFECTS PHONE INPUTS ONLY.)

INPUT

(MONO)

Example: (A) Find the peak music power of your loudspeaker (such as 75 watts). (B) Find the loudspeaker impedance (8 ohms). (C) Draw a line between points A and B. The line intersects the middle scale at the correct fuse value (1.5 amps).

1.0

1.2

1.4

1.6

2.5

Example:

Impedance = 8 ohms.

Peak Power = 75 W

Answer: Fuse = 1.5 A

(ohms)

LOUDSPEAKER IMPEDANCE

FUSE

(amps)

1.5

.15

.08

3000

2000

1500

1000 800

600

400

300

200

150

100 80

10 8

LOUDSPEAKER RATING

PEAK MUSIC POWER

1.5

(Typically 4 times the continuous average power)

(watts)

2.4 Additional Load Protection

To protect against excessive power, a fuse can be added in series with each loudspeaker cable. A single fuse can protect the entire system, or one can be used for each driver. High-frequency drivers (tweeters) are usually more sensitive to large voltage peaks, while low-frequency drivers (woofers) are typically most sensitive to the heat from average (RMS) output power. To protect your tweeters, we recommend that you use a high-speed instrument fuse like the Littlefuse 361000 series. To protect your woofers, we recommend using a slow-blow fuse that more closely represents the thermal response of your woofer. Use Figure 2.5 to find the correct value for either type of fuse.

Page 10

Fig. 2.5 Loudspeaker Fuse Nomograph

2.5 Required AC Mains

All

Power Base

priate line cord and plug. When possible, use a power receptacle on a dedicated circuit, and always make sure it will provide the right voltage and sufficient current. We do not recommend operating your amplifier with voltages greater than 10% above or below the unit’s rated voltage. For example, if your amplifier is rated for 120 VAC, the line voltage should not exceed 132 VAC.

amplifiers are shipped with an appro-

Page 47

Power Base Series Power Amplifiers

3 Operation

3.1 Precautions

Although your amplifier is protected from external faults, the following safety precautions are recommended:

1. There are important differences among the Stereo, Bridge-Mono and Parallel-Mono operating modes. Please refer to Sections 2 for additional information.

2. WARNING: Do not change the position of the stereo/mono switch unless the amplifier is first turned off.

3. CAUTION: In Parallel-Mono mode, a jumper is used to connect the red binding post outputs. Be sure to remove this jumper for Bridge-Mono or Stereo mode, or high distortion and excessive heating will occur. Also, make sure the stereo/

mono switch is set to the proper position.

4. Use care when making connections, selecting signal sources and controlling the output level. The load you save may be your own!

5. Do not short the ground lead of an output cable to the input signal ground. This will form a ground loop and may cause oscillations.

6. Operate the amplifier from AC mains of not more than 10% variation above or below the selected line voltage and only at the specified line frequency.

7. Never connect the output to a power supply output, battery or power main. Such connections

may result in electrical shock.

8. Tampering with the circuitry by unqualified personnel or making unauthorized circuit changes may be hazardous and invalidates all agency listings.

Remember: Crown is not liable for any damage that results from overdriving other system components.

3.2 Power Indicator

When lit, the amber power indicator (to the left of the power switch) shows that the amplifier has been turned on. It is driven only by the low-voltage power supply and does not indicate the status of the high-voltage supplies.

3.3 Protection Systems

Power Base

tems, including protection, transformer thermal protection and fuses or circuit breakers that protect the power supplies.

amplifiers have extensive protection sys-

ODEP

, ultrasonic/RF protection, drive

3.3.1

ODEP

Crown invented under demanding conditions and to increase output efficiency. To do this, Crown established a rigorous program to measure each transistor’s (SOA). Intelligent circuitry was then designed to simulate the instantaneous conditions of the output transistors. Its name describes what it does: Output Device Emulation Protection, or compares transistor conditions to their known SOA. If more power will be asked of them than they can deliver under the existing conditions, until conditions fall within the SOA. Limiting is proportional and kept to an absolute minimum—only what is required to prevent output transistor damage. Under normal conditions, no limiting is required and transparent to the audio signal.

ODEP

makes possible a quantum leap in output effi-

ciency and reliability—with

3.3.2 Ultrasonic and Radio Frequency Protection

An amplifier’s slew rate only needs to be large enough to deliver the maximum voltage at the highest required frequency. Higher slew rates actually allow undesirable ultrasonic and radio frequencies to be reproduced. By design, rate to limit the highest frequencies that they reproduce. Limiting occurs well above 20 kHz so there is no audible effect on performance. This approach protects the amplifier from radio frequencies and can even protect some sensitive loads (including some tweeters).

3.3.3 Drive Protection

The drive protection system temporarily removes output drive to protect the amplifier and its loads. Drive protection can be activated in two situations. First, if dangerous subsonic frequencies or direct current (DC) is detected in the amplifier’s output, the unit will activate its DC/lowfrequency protection circuitry which puts the amplifier in drive protection mode. This protects the loads and prevents oscillations. The unit resumes normal operation as soon as the amplifier no longer detects dangerous output. Although it is extremely unlikely that you will ever activate the amplifier’s DC/low frequency protection system, improper source materials like subsonic square waves or input overloads that excessively clip the input signal can activate this system.

The amplifier’s fault protection system will put the amplifier in drive protection mode in rare situations where heavy common-mode current is detected in the output.

Power Base

ODEP

to keep the amplifier working

safe operating area

ODEP

. In simple terms,

ODEP

limits the drive

ODEP

, the show goes on.

amplifiers have a controlled slew

ODEP

Page 11

Page 48

Power Base Series Power Amplifiers

The unit should never output heavy common-mode current unless its circuitry is damaged. Activating drive protection helps prevent further damage.

3.3.4 Transformer Thermal Protection

All

Power Base

amplifiers have transformer thermal protection. This protection circuitry is activated in unusual situations where the unit’s transformer temperature rises to unsafe levels. Under these abnormal conditions, the unit removes power to the high-voltage transformer. The fan will continue to run in all units except those with 220/240 VAC transformers. The amplifier will return to normal after it cools to a safe temperature.

It is very unlikely that your

Power Base

amplifier will ever activate transformer thermal protection as long as it is operated within rated conditions. Your amplifier is designed to continue operating under conditions where other amplifiers would fail. But even when you exceed the limits of a

Power Base

amplifier, it still pro-

tects itself—and your investment—from damage.

3.3.5 Fuses and Circuit Breakers

All 120 VAC, 60 Hz units and all

Power Base-3

units have a fuse that protects the low-voltage power supply and cooling fan. The

Power Base-1

and

Power Base-2

high-voltage power supplies are protected by fuses, while the

Power Base-3

high-voltage power supplies are protected by a circuit breaker. With rated loads and output levels, these fuses (or the circuit breaker) should only shut down the amplifier in the incredibly rare instance of a catastrophic amplifier failure. The

ODEP

protection system keeps the amplifier operational under most other severe conditions. The fuses (or breaker) can also shut down the amplifier in situations where extremely low-impedance loads and high output levels result in excessive current draw.

Power Base

amplifier will not blow its fuses or trip its breaker unless something is wrong. In the rare event that an internal fuse blows, please refer the unit to a qualified technician. If the breaker in a

Power Base-3

trips, try to identify and correct the problem before resetting it with the back panel Circuit Breaker Reset. If the problem persists, refer the unit to a qualified technician.

3.4 Controls

The Power switch is th only control located on the front panel. All others are located on the rear, including the level controls.

When making any setup or wiring changes, don’t forget to turn off the amplifier, turn down the level controls and disconnect the power cord. Be sure to turn down (full counterclockwise) the channel 2 level control when using either mono mode. The Parallell Mono/Stereo/ Bridge Mono switch is used to select Stereo, BridgeMono or Parallel-Mono operating modes. The Input Ground Lift switch isolates the phone jack input grounds from the chassis ground to help prevent ground loops. It does not affect any installed input accessories. The Input Sensitivity Switch, located inside the back cover plate, sets the amplifier’s input sensitivity (refer to subsection 2.3 for information on changing this switch). And the

Power Base-3

has a back panel Circuit Breaker Reset button that resets the circuit breaker (refer to subsection 3.3.5).

CHANNEL 2

LEVEL CONTROL

CH-2

567

GAIN

INPUT GROUND LIFT

INPUT

LIFT

(AFFECTS PHONE INPUTS ONLY.)

INPUT

(MONO)

Fig. 3.1 Back Panel Level Controls

CHANNEL 1

LEVEL CONTROL

CH-1

567

8 3 2

GAIN

9 10

3.5 Filter Cleaning

A dust filter is provided on the unit’s air intake. If it becomes clogged, the unit will cool less efficiently and may produce lower output levels. To clean the filter, use a phillips screwdriver to remove the three screws the secure the front grille. Use mild dishwashing detergent and warm water for best cleaning results. Be sure the filter is dry before you reinstall it. Replacement filters may be ordered from the factory.

Dust filters are not 100% efficient—long term this may require internal heat-sink cleaning by a qualified technician. Internal cleaning information is available from our Technical Support Group.

Page 12

Page 49

Power Base Series Power Amplifiers

4 Specifications

All specifications apply to units in Stereo mode with 8-ohm loads and an input sensitivity of 26 dB unless otherwise specified.

Standard 1 kHz Power: refers to maximum average power in watts at 1 kHz with 0.1% THD+ noise.

Full Bandwidth Power: refers to maximum average power in watts from 20 Hz to 20 kHz with 0.1% THD+ noise.

120 VAC, 60 Hz Units: refers to amplifiers with dedicated transformers for 120 VAC, 60 Hz power mains.

Performance

Frequency Response: ±0.1 dB from 20 Hz to 20 kHz at 1 watt.

Phase Response: ±10 degrees from 10 Hz to 20 kHz at 1 watt.

Signal-to-Noise: A-weighted, better than 105 dB below full bandwidth power. Better than 100 dB below full bandwidth power from 20 Hz to 20 kHz.

Total Harmonic Distortion (THD): Less than 0.05% at full bandwidth power from 20 Hz to 1 kHz increasing linearly to 0.1% at 20 kHz.

Intermodulation Distortion (IMD): (60 Hz and 7 kHz 4:1) Less than 0.05% from less than 158 milliwatts to full bandwidth power.

Damping Factor: Greater than 1,000 from 10 Hz to 400 Hz. Crosstalk

Power Base-1

width power from 50 Hz to 2 kHz, rising linearly to greater than 60 dB at 20 kHz.

Power Base-2

width power from 50 Hz to 2 kHz, rising linearly to greater than 66 dB at 20 kHz.

Power Base-3

width power from 50 Hz to 4 kHz, rising linearly to greater than 70 dB at 20 kHz.

Common Mode Rejection (CMR): Better than 70 dB below rated full bandwidth power from 20 Hz to 1 kHz falling linearly to better than 50 dB at 20 kHz.

Controlled Slew Rate: Greater than 13 volts/ms.

Voltage Gain: 20:1 ±3% or 26 dB ±0.25 dB at the maxi-

mum level setting (Input Sensitivity switch set to its 26 dB position).

Power Base-1

volt sensitivity; 28:1 ±12% or 29.1 dB ±1 dB at 1.4 volt sensitivity.

: Greater than 75 dB below full band-

: Greater than 90 dB below full band-

: 51:1 ±12% or 34.3 dB ±1 dB at 0.775

Power Base-2

: 64:1 ±12% or 36.2 dB ±1 dB at 0.775 volt sensitivity; 35:1 ±12% or 31.0 dB ±1 dB at 1.4 volt sensitivity.

Power Base-3

: 83:1 ±12% or 38.4 dB ±1 dB at 0.775 volt sensitivity; 46:1 ±12% or 33.3 dB ±1 dB at 1.4 volt sensitivity.

Power

Output Power:

teed minimums for standard 1 kHz power. For more information, see the power matrices in Figures 4.1 through 4.6 (maximum average power @ 0.1% THD + N).

Power Base-1

Stereo mode (both channels driven):

Bridge-Mono mode:

Parallel-Mono mode:

Power Base-2

Stereo mode (both channels driven):

Bridge-Mono mode:

Parallel-Mono mode:

Power Base-3

Stereo mode (both channels driven):

Bridge-Mono mode:

1525 watts into 8 ohms. 1090 watts into 16 ohms.

Parallel-Mono mode:

1530 watts into 2 ohms. 1080 watts into 4 ohms.

Load Impedance: Safe with all types of loads. Rated for 4 to 8 ohms in Stereo, 8 to 16 ohms in BridgeMono and 2 to 4 ohms in Parallel-Mono mode.

The following specifications are guaran-

240 watts into 4 ohms. 200 watts into 8 ohms.

455 watts into 8 ohms. 395 watts into 16 ohms.

455 watts into 2 ohms. 400 watts into 4 ohms.

460 watts into 4 ohms. 325 watts into 8 ohms.

910 watts into 8 ohms. 660 watts into 16 ohms.

920 watts into 2 ohms. 655 watts into 4 ohms.

760 watts into 4 ohms. 540 watts into 8 ohms.

Page 13

Page 50

Power Base Series Power Amplifiers

Required AC Mains: Current, frequency and voltage

requirements are provided on each unit’s back panel. All models draw 90 watts or less at idle.

Power Base-1

Power Base-2

Power Base-3

Low-Voltage Power Supply: A ±24 VDC fanformer supply (fan motor winding) regulated to ±15 VDC.

AC Connector: An appropriate AC line cord and plug are provided. 120 VAC, 60 Hz units have a standard 3-wire, 15-amp grounded connector (NEMA 5-15P).

: Draws up to 6 amps of current.

: Draws up to 10 amps of current.

: Draws up to 15 amps of current.

Controls

Power: A front panel rocker switch used to turn the amplifier on and off.

Level: A back panel rotary potentiometer for each channel used to control the output level.

Stereo/Mono: A three-position back panel switch used to select Stereo, Bridge-Mono or Parallel-Mono mode.

Sensitivity: A three-position switch inside the back cover plate used to select the input sensitivity for both channels: 0.775 volts or 1.4 volts for standard 1 kHz power, or 26 dB voltage gain (see Section 2.3).

Input Ground Lift: A two-position back panel switch used to isolate the phone jack and chassis grounds.

Reset (

ton used to reset the circuit breaker that protects the power supplies.

Power Base-3

only): A back panel push but-

Indicators

Power: This amber indicator shows the on/off status of the low voltage power supply.

Input/Output

Input Connector: Balanced ¼ inch phone jacks. See Section 5 for XLR and barrier block accessories.

Input Impedance: Nominally 20 K ohms, balanced; 10 K ohms, unbalanced.

Output Connector: Two sets of color-coded 5-way bbinding posts (for banana plugs, spade lugs or bare wire).

Output Impedance: Less than 10 milliohms in series with less than 2 microhenries.

DC Output Offset: Less than 10 millivolts.

Output Signal

Stereo: Unbalanced, two-channel.

Bridge-Mono: Balanced, single-channel. Channel 1

controls are active; Channel 2 controls should be turned down and not used.

Parallel-Mono: Unbalanced, single-channel. Channel 1 controls are active; Channel 2 controls should be turned down and not used.

Protection

Power Base

open or mismatched loads; overloaded power supplies; excessive temperature, chain destruction phenomena, input overload and high-frequency blowups. They also protect loudspeakers from input and output DC, as well as providing protection from turn-on/turn-off transients.

If operating conditions are unreasonable, the patented

ODEP

tect the output transistors, particularly in the case of elevated temperature. A thermal switch imbedded in the transformer protects the power supplies from overload. In the rare event that a transformer overheats, the thermal switch removes power, waits until the unit has cooled to a safe temperature and then resets itself.

Turn On: Four second delay with no dangerous transients. Contact us if you need to change the delay.

amplifiers are protected against shorted,

circuitry proportionally limits the drive level to pro-

Construction

Durable black finish on steel chassis with special “flowthrough” ventilation from front to side panels.

Cooling: Internal heat sinks with forced-air cooling for rapid, uniform heat dissipation.

Dimensions: Standard 19-inch (48.3 cm) rack mount width (EIA RS-310-B), 3.5-inch (8.9 cm) height and 16-inch (40.6 cm) depth behind the mounting surface.

Approximate Weight: Center of gravity is 6 inches (15.2 cm) behind front mounting surface.

120 VAC, 60 Hz Units:

Power Base-1

(15.4 kg) shipping weight.

Power Base-2

(17.2 kg) shipping weight.

Power Base-3

(18.2 kg) shipping weight.

: 30 pounds (13.6 kg) net; 34 pounds

: 34 pounds (15.4 kg) net; 38 pounds

: 36 pounds (16.3 kg) net; 40 pounds

Page 14

Page 51

Power Base Series Power Amplifiers

Crown specifications are guaranteed for three years.

In an effort to provide you with as much information as possible about the high power-producing capabilities of your amplifier, we have created the following power matrices.

Minimum Power Specifications

Crown’s minimum power specifications represent the absolute smallest amount of output power you can expect from your amplifier when it is driven to full output under the given conditions. Some spaces in each matrix may be left blank because the same guarantee is not provided for those conditions—however, your amplifier will perform well under all conditions listed in each matrix.

When measuring power, 0.1% THD appears to be the industry standard for distortion. Two of the maximum average power specifications shown in each minimum power matrix are measured at 0.1% THD so you can easily compare Crown specifications to those of other manufacturers. But this high level of distortion actually allows for some clipping which is undesirable. Because of this, a maximum average power spec at 0.05% THD is included in each minimum power matrix which represents non-clipped conditions. Although most manufacturers do not give you power specifications at 0.05% THD, we encourage them to provide these specifications so you will have a more realistic representation of the way amplifiers should be used in the real world—without a clipped output signal.

Many manufacturers publish power specs with a tolerance of ±1 dB or worse. This means their amplifier can deviate more than 20% in output! A 100 watt amplifier would meet their specification if it only produced 79.4 watts. Other manufacturers qualify their specs by saying they are “typical,” “subject to manufacturing tolerances,” “single channel driven” or that they are specified with “fuses bypassed.” Each of these statements effectively removes any performance guarantee. In fact, some manufacturers use these tactics to generate large power numbers, and they don’t even print a disclaimer. We take a different approach at Crown—our amplifiers are their specifications for three years. Further, because our published specs are set below our “in-house” measurements, you can expect Crown amplifier to

Minimum Power Notes:

All minimum power specifications are based on 0.1% regulated AC mains and an ambient room temperature of 70° F (21° C). A 100V, 50Hz model was used because of its higher current demand. The standard EIA power measurement (RS-490) is not identified here because it is identical to the FTC Continuous Average Power specification.

1. A 1 kHz sine wave is presented to the amplifier and the output monitored for nonlinear distortion. The level is increased until the THD reaches 0.1%. At this level the average power per channel is reported.

2. A sine wave is presented to the amplifier over the range from 20 Hz to 20 kHz and the output monitored for nonlinear distortion. The level at each frequency is increased until the THD reaches 0.1%. At this level the average power per channel is reported.

3. A 1 kHz sine wave is presented to the amplifier and the output monitored for nonlinear distortion. The level is increased until the THD reaches 0.05%. At this level the average power per channel is reported.

4. Continuous power in the context of Federal Trade Commission testing is understood to be a minimum of five minutes of operation. Harmonic distortion is measured as the RMS sum total and given as a percentage of the fundamental output voltage. This applies for all wattages greater than 0.25 watts.

exceed

its published minimum power specs. We believe you should get what you pay for.

guaranteed

to meet or exceed

every

Power Base-1 – Minimum Guaranteed Power (Watts)

Stereo-Mono

Mode

AC Mains120 VAC, 60 Hz Units

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

Parallel-Mono

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

International Units

Parallel-Mono

Fig. 4.1 Power Base-1 Minimum Power Matrix

0.1% THD+N (See note 1)

Load (Ohms)

4 8 8

4 4 8 8

Maximum Average

1 kHz

240

200

455

395

455

400

230

205

465

410

440

410

0.1% THD+N (See note 2)

20Hz-20kHz

175

185

360

370

165

185

355

375

0.05% THD+N (See note 3)

1 kHz

235

200

455

390

445

395

225

200

455

405

430

405

FTC Continuous Average

0.1% THD + Noise (See note 4)

1 kHz 20Hz-20kHz

200

390

200

390

180

350

175

350

Page 15

Page 52

Power Base Series Power Amplifiers

Power Base-2 –

Stereo-Mono

Mode

AC Mains120 VAC, 60 Hz Units

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

Parallel-Mono

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

International Units

Parallel-Mono

Fig. 4.2 Power Base-2 Minimum Power Matrix

0.1% THD+N (See note 1)

Load (Ohms)

4 8 8

4 4 8 8

2 4

Minimum Guaranteed Power (Watts)

Maximum Average

1 kHz

460

325

910

660

920

655

425

310

855

620

850

620

0.1% THD+N (See note 2)

20Hz-20kHz

425

310

830

615

390

290

775

575

0.05% THD+N (See note 3)

1 kHz

460

325

905

655

915

650

425

305

850

615

845

615

FTC Continuous Average

0.1% THD + Noise (See note 4)

1 kHz 20Hz-20kHz

385

310

815

625

805

630

395

305

790

615

785

610

265

530

325

275

640

545

Power Base-3 –

Stereo-Mono

Mode

AC Mains120 VAC, 60 Hz Units

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

Parallel-Mono

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

International Units

Parallel-Mono

Fig. 4.3 Power Base-3 Minimum Power Matrix

0.1% THD+N (See note 1)

Load (Ohms)

4 8 8

4 4 8 8

2 4

Minimum Guaranteed Power (Watts)

Maximum Average

1 kHz

760

540

1525

1090

1530

1080

680

510

1335

1025

1365

1015

0.1% THD+N (See note 2)

20Hz-20kHz

715

525

1430

1045

630

495

1240

980

0.05% THD+N (See note 3)

1 kHz

755

540

1500

1075

1520

1080

660

505

1305

1000

1340

1010

FTC Continuous Average

0.1% THD + Noise (See note 4)

1 kHz 20Hz-20kHz

530

1055

1065

555

510

1115

1025

1115

1030

495

985

485

470

1085

930

Page 16

Page 53

Power Base Series Power Amplifiers

Maximum Power Specifications

Crown’s maximum power specifications represent the largest amount of output power you can expect from your amplifier when it is driven to full output under the given conditions. These specifications can be used to prevent loudspeaker and hearing damage.

The maximum power matrices include specifications for single cycle and 40 millisecond burst sine waves. Burst signals act like large transient peaks that are present in common source signals. Loudspeakers can respond to a single cycle burst, so the single cycle burst specifications should be used to help you protect your loudspeakers. In contrast, a 40 millisecond burst represents the typical response time of the human ear. Your ear will not respond to the entire dynamic change of a burst that lasts less than 40 milliseconds.

The specifications are provided at 0.05% THD because this represents a low distortion condition. To help you operate your amplifier within these tolerances, Crown’s premium amplifiers include an input/output comparator that shows when the amplifier has exceeded 0.05% THD. Operating the amplifier at levels higher than 0.05% THD can result in output power levels that are higher than those listed in the maximum power matrices.

Maximum Power Notes:

All maximum power specifications are based on 0.1% regulated AC mains and an ambient room temperature of 70° F (21° C). A 100V, 50Hz model was used because of its higher current demand. Although it is an unusual condition, your amplifier can function well with AC mains voltages up to 10% over the specified line voltage. With overvoltage conditions, your amplifier may be capable of delivering instantaneous power levels up to 20% greater than the specifications in the matrix.

1. A single cycle sine wave is presented to the amplifier and monitored for nonlinear distortion. The average power during the burst is reported. Loudspeakers must be able to withstand this level if they are to be safely used with this amplifier.

2. A 40 millisecond sine wave burst (10 percent duty cycle) is presented to the amplifier and monitored for nonlinear distortion. The average power during the burst is reported. This power level is a measurement of the amplifier’s maximum transient power that can be perceived by the human ear.

Stereo-Mono

Mode

AC Mains120 VAC, 60 Hz Units

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

Parallel-Mono

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

International Units

Parallel-Mono

Fig. 4.4 Power Base-1 Maximum Power Matrix

Load (Ohms)

4 8 8

2 4 4 8 8

Power Base-1 –

Single Cycle Tone Burst

At less than 0.05% THD

(See note 1)

50 Hz

325

265

630

540

635

530

325

290

640

580

620

580

1 kHz

335

310

640

630

645

615

330

345

650

690

625

690

Maximum Power (Watts)

40 Millisecond Tone Burst

0.05% THD + Noise (See note 2)

7 kHz 50 Hz

335

300

620

610

640

600

330

335

670

625

670

315

230

600

470

620

465

320

260

635

520

615

515

1 kHz 7 kHz

295

220

565

440

580

430

315

235

625

470

615

475

310

230

580

455

605

450

330

250

655

495

625

490

Page 17

Page 54

Power Base Series Power Amplifiers

Stereo-Mono

Mode

AC Mains120 VAC, 60 Hz Units

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

Parallel-Mono

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

International Units

Parallel-Mono

Power Base-2 –

Single Cycle Tone Burst

At less than 0.05% THD

(See note 1)

Load (Ohms)

50 Hz

655

460

1410

915

1440

915

4 4

720

465

1440

920

1390

915

Maximum Power (Watts)

1 kHz

805

525

1850

1060

1685

1055

900

530

1770

1055

1670

1055

7 kHz 50 Hz

790

515

1805

1020

1645

1020

885

510

1785

1020

1655

1015

40 Millisecond Tone Burst

0.05% THD + Noise (See note 2)

550

400

1190

795

1185

805

605

410

1200

820

1185

820

Fig. 4.5 Power Base-2 Maximum Power Matrix

1 kHz 7 kHz

500

375

1090

755

1085

750

545

380

1075

750

1065

750

520

395

1125

780

1120

775

565

395

1120

785

1110

775

Stereo-Mono

Mode

AC Mains120 VAC, 60 Hz Units

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

Parallel-Mono

Stereo

(both channels

driven)

Bridge-Mono

(balanced output)

International Units

Parallel-Mono

Power Base-3 –

Single Cycle Tone Burst

Load (Ohms)

50 Hz

1090

715

2155

1415

2140

1420

1190

785

2355

1540

2330

1570

At less than 0.05% THD

(See note 1)

Maximum Power (Watts)

1 kHz

1575

870

3140

1740

3135

1735

1750

960

3490

1915

3485

1895

7 kHz 50 Hz

1525

838

3040

1675

3015

1665

1695

920

3380

1840

3345

1825

40 Millisecond Tone Burst

0.05% THD + Noise (See note 2)

910

610

1780

1250

1790

1225

970

675

1945

1360

1940

1360

Fig. 4.6 Power Base-3 Maximum Power Matrix

1 kHz 7 kHz

815

570

1615

1135

1605

1135

870

625

1725

1235

1720

1235

855

595

1690

1180

1680

1170

920

645

1805

1285

1800

1270

Page 18

Page 55

Power Base Series Power Amplifiers

5 Accessories

There are two accessories available at the time of this printing: the

MT-XLR

Factory Service Center or the Crown factory.

5.1 MT-XLR

The

MT-XLR

standard 3-pin female XLR input connectors. The

MT-XLR

connections in a system that uses standard XLR connectors. It can also be used in systems that need to daisy chain an input signal from one amplifier to an-

MT-XLR

and

MT-BB

and the

MT-BB

. Important: The

must be installed at a Crown

is an accessory panel that provides two

accessory makes it easy to quickly change

other. Because the

MT-XLR

connectors are wired in parallel with the amplifier’s built in phone jack connectors, an input signal fed to either input can be fed to another amplifier from the unused connector for that channel.

5.2 MT-BB

The

MT-BB

is an accessory panel that provides barrier strip input connectors. An desirable in applications requiring bare wire connections. It can also be used to daisy chain an input signal from one amplifier to another just like the

MT-BB

accessory might be

MT-XLR

CH-2 INPUT CH-1 INPUT

PUSHPUSH

THESE XLR INPUTS ARE CONNECTED IN PARALLEL WITH THE PHONE JACK INPUTS.

Fig. 5.1 The MT-XLR

MT-BB

GND

CH-2 INPUT CH-1 INPUT

Fig. 5.2 The MT-BB

– +– +

Page 19

Page 56

Page 57

Page 58

Page 59

Page 60

Crown PB-1, Power Base 1 Service manual

Specifications and Main Features

Frequently Asked Questions

User Manual