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TECHNICAL SPECIFICATIONSTECHNICAL SPECIFICATIONS

TECHNICAL SPECIFICATIONS

Dimensions: (WxHxD) 483x88x445mm (2U)

Weight: 16Kg

Power Requirements: (230Vac±15% 50/60Hz) 1000VA

(115Vac±15% 50/60Hz) 1000VA

Output Power: (4Ω stereo/parallel) 2x 500Watts

(8Ω stereo/parallel) 2x 350Watts

(8Ω bridge) 1000Watts

(16Ω bridge) 700Watts

Max. Undistorted Out: (4Ω stereo/parallel) 126Vpp

(8Ω stereo/parallel) 149Vpp

(8Ω bridge) 250Vpp

Input Sensitivity: (constant sensitivity) 0.775Vrms (0dB)

(constant gain) 2.25Vrms (+9.2dB)

Input Impedance: (balanced) 30KΩ

(unbalanced) 15KΩ

Voltage Gain: (constant sensitivity) 35±0.5dB

(constant gain) 26±0.5dB

Slew Rate: 25V/µS

Damping Factor: (4Ω stereo/parallel) >400

(8Ω stereo/parallel) >800

Frequency Response (-0.2dB) 20Hz÷20KHz

at Full Power: (-3dB) 10Hz÷60KHz

IMD: (SMPTE 60Hz/7KHz 4:1) <0.1%

THD: (THD+N) <0.1%

S/N Ratio: (unweighted) >95dB

Crosstalk: (1KHz) >70dB

TEST PROCEDURES & ADJUSTMENTSTEST PROCEDURES & ADJUSTMENTS

TEST PROCEDURES & ADJUSTMENTS

PrecautionPrecaution

Precaution

➭ To prevent short circuit during any test,

the oscilloscope must bethe oscilloscope must be

the oscilloscope must be

EARTH insulatedEARTH insulated

EARTH insulated, this occurs because some test require to connect its

probe to the amplifier output, non-compliance may cause damages to

oscilloscope inputs circuitry.

➭ Before removing or installing any modules and connectors,

disconnectdisconnect

disconnect

the amplifier from AC MAINSthe amplifier from AC MAINS

the amplifier from AC MAINS and measure the DC supply voltages

across each of the power suppliy capacitors. If your measurement on any

of the caps is greater than 10Vdc, connect a 100Ω 100W resistor across

the applicable caps to discharge them for your safety. Remember to

remove the discharge resistor immediately after discharging caps.

Do notDo not

Do not

power up the amplifier with the discharge resistor connectedpower up the amplifier with the discharge resistor connected

power up the amplifier with the discharge resistor connected.

➭ Read these notes entirely before proceeding to any operation. These

notes are not comprehensive of all damages that possibly occur, but

includes some specifically advices, checks and adjustments relative to

this amplifier.

RemarksRemarks

Remarks

➭ The output coupled transistors TR6-TR11 (MJ15022/B) and TR16-TR22

(MJ15023/B) are factory selected on V

and V

BREAKDOWN

EC0<

-6.6mA at

(BR)CE0

=11V for NPN and I

EC0

<6.6mA at V

(BR)CE0

=-11V for PNP)

The selection is marked by a red digit (from 0 to B) representative of V

forward voltage categories, these are subdivided in 12 steps of 30mV

each.

Only selected transistors must be used when replacing TR6-TR11 orOnly selected transistors must be used when replacing TR6-TR11 or

Only selected transistors must be used when replacing TR6-TR11 or

TR16-TR22 and every coupled transistors must have the same digit.TR16-TR22 and every coupled transistors must have the same digit.

TR16-TR22 and every coupled transistors must have the same digit.

➭ The power supply utilizes a dual bipolar DC rail configuration with low and

high voltages; one positive and one negative low rail (+/-Vcc1) and one

positive and one negative high rail (+/-Vcc2).

Visual CheckVisual Check

Visual Check

➭ Use compressed air to clear dust in the amplifier chassis.

➭ Before proceed to supply the amplifier check visually the internal assem-

bly, if appears an evident damage find the most possible reasons that

cause it.

➭ Check the wiring cables for possible interruptions or shorts.

➭ If the damage has burnt a printed circuit board don’t try to repair it, re-

place with a new one.

Test InstrumentTest Instrument

Test Instrument

➭ Audio Generator

➭ Dual Trace Oscilloscope

➭ Digital Multimeter

➭ 2Ω 2000W, 4Ω 1000W, 8Ω 1000W, 100Ω 100W resistors

➭ Variac

➭ Temperature Meter

SetupSetup

Setup

➭ Connect the Variac between the PROTECTION board and the TF1 and

TF2 transformers and set it at zero voltage.

➭ Set the amplifier in STEREO MODE and turn full clockwise the LEVEL

potentiometers.

➭ Connect the audio generator to the channel inputs and set it to 1KHz

775mV

RMS

(0dB) sinusoidal signal.

➭ Insert the temperature meter through the IC1 interstice located at centre

of heatsink.

➭ The procedures that follow must be executed subsequently in the order

specified.

Supply CheckSupply Check

Supply Check

➭ Remove the transformer secondary fuses (located on FUSE board), set

the Variac to the nominal mains voltage, check with the Multimeter the

phase opposition between the secondaries of the two transformers (F1-

F2,F3-F4), if not, verify the primary connections (T1÷T4 on Protections

Board).

➭ Verify the AC supply voltages: F1-F2=72±2Vac F3-F4=128±3Vac.

➭ Re-set the Variac at zero voltage, turn off the amplifier and put the fuses

back on its holders.

➭ Connect the oscilloscope probes CH1/2 to the channel outputs, set both

to 20V/div. 200µS/div.

➭ Set up the Variac slowly monitoring the Outputs with the oscilloscope

CH1/2 connected, it should display the sinusoidal input signal amplified

with no distortions, if a distortion occur check the Driver and the Power

Boards as suggested in the ADVICES section.

➭ If the protection trips, turn off the amplifier, wait some minutes and dis-

connect the supplies from the outputs modules (CN1 - CN2 - CN7 - CN8

on POWER boards), continue to check the supplies.

➭

CAUTION: Before re-connecting the output modules to the supplies,CAUTION: Before re-connecting the output modules to the supplies,

CAUTION: Before re-connecting the output modules to the supplies,

you must have the capacitors discharged for your safety: connect ayou must have the capacitors discharged for your safety: connect a

you must have the capacitors discharged for your safety: connect a

100100

100

ΩΩ

Ω

100W resistor across the caps and remove the resistor just 100W resistor across the caps and remove the resistor just

100W resistor across the caps and remove the resistor just

after they are discharged.after they are discharged.

after they are discharged.

➭ Finally verify the DC supplies on Supply Board:

CN6 (+Vcc2) =+89.5±2Vdc

CN8 (+Vcc1) =+50±1.5Vdc

CN7 (-Vcc1) =-50±1.5Vdc

CN2 (-Vcc2) =-89.5±2Vdc

on Protections Board:

CN2 pin3 =+27±1Vdc

CN3 pin3 =-27±1Vdc

CN1 pin4-5-6 =+13.8±1Vdc

CN1 pin1-2-3 =-13.8±1Vdc

➭ If one or more voltages don’t correspond, check the rectifiers, capacitors

and transformers disconnecting them from circuitry, refer to schematics.

Channels CheckChannels Check

Channels Check

➭ The channel A is facing the front and channel B the rear of the chassis.

➭ These procedures are intended for one channel at a time, repeat these

operation for the other channel.

➭ Verify, with the Multimeter, the insulation between the heatsink and the

transistors collectors.

➭

SETUP:SETUP:

SETUP:

Connect the CH1 scope GND clip to CN5 (GND terminal).

Connect the CH1 probe tip to CN6 (AMP output).

Connect the CH2 probe tip to D2 cathode on POWER board.

Set the LEVEL potentiometers full clockwise.

The load resistor is disconnected.

➭

INITIAL TEST:INITIAL TEST:

INITIAL TEST:

Increase slowly the Variac. The channel output signals must be symmetri-

cal respect the GND without visible distortion and oscillation as shown in

Fig.1 Trace A

. If there is a distortion read the section ADVICES and

proceed to check the other channel.

Verify that, when the heatsink temperature is less 50°c, the cooling fan

Fig. 1Fig. 1

Fig. 1

Trace B (20V/div.)

Trace A (20V/div.)

Trace C (20V/div.)

Brand	LEM
Model	P1000
Category	Amplifier
Language	English

LEM P1000 User Manual

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LEM P1000 Specifications

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