LEM Hurricane H100MA Service Manual Download Page 4

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General Precaution

• To prevent short circuit during any test,

the oscilloscope must be EARTH insulated

this occurs because some test require to connect its probe to the ampliﬁ er output, non-com-
pliance may cause damages to oscilloscope inputs circuitry.
•  Before removing or installing any modules and connectors, disconnect the ampliﬁ er 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 10W resi-
stor across the applicable caps to discharge them for your safety. Remember to remove the
discharge resistor immediately after discharging caps. Do not power up the ampliﬁ er with
the discharge resistor connected.
•  Read these notes entirely before proceeding to any operation. These notes are not com-
prehensive of all damages that possibly occur, but includes some speciﬁ cally advices, checks
and adjustments relative to this ampliﬁ ed speaker.
•  Do not check the ampliﬁ er with the speaker connected use only an appropriate load
resistor.
•  BE CAREFUL increasing the Variac you must not exceed the nominal mains voltage plus
its tolerance (see speciﬁ cations) any upper voltage can be cause of damage.

Visual Check

•  Check the speakers for any damaging (cone-breaking, interruption or so).
•  Before proceed to supply the ampliﬁ er check visually the internal assembly, if appears
an evident damage ﬁ nd 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, replace with a new
one.

Test Instruments

• Audio

Generator

• Dual Trace Oscilloscope
• Digital

Multimeter

• Temperature

Meter

• 8

500W, 4

500W, 100

10W resistors

• Variac

(0÷250Vac)

H100MA CHECKING & ADJUSTMENTS

The following adjustment and notes are relative to these models only.

Technical Specifications

Dimensions: .....................H100MA (WxHxD) ................................ 305x395x275mm
Weight: ............................H100MA .............................................. 13Kg
Power Requirements: .........(230Vac±10% 50Hz) ............................ 150VA
.......................................(115Vac±10% 50/60Hz) ....................... 150VA
Output Power*: .................(8

) ................................................... 90W

Max.Undistorted Out*: .......(8

) ................................................... 76Vpp

Sensitivity: .......................H100MA (1W/1m) ................................ 92.6dB

SPL

Max SPL: ..........................H100MA (continuous) ........................... 112dB

SPL

.......................................H100MA (peak) .................................... 115dB

SPL

Frequency Response ..........(ampliﬁ er+speaker) .............................. 65Hz÷20KHz
.......................................(only ampliﬁ er -3dB)............................. 10Hz÷60KHz
Input Sensitivity: ...............(0dB) .................................................. 0.775V

RMS

Input Impedance: ..............(balanced) ........................................... 30K

.......................................(unbalanced) ....................................... 15K

Voltage Gain: .............................................................................. 31±1dB
IMD: ................................(SMPTE 60Hz/7KHz 4:1)........................ <0.1%

THD: ...............................(THD+N) ............................................. <0.1%
S/N Ratio: ........................(unweighted) ....................................... >100dB
*Note: measured with the limiter enabled.

Setup

• Verify, with the Multimeter, the insulation between the heatsink and the transistors col-
lectors. Also see Advices section.
• Verify, with the Multimeter, the PTC resistor value (TH1), it must be between 50

and

200

•  Connect the Variac between the mains and the ampliﬁ er and set it at zero voltage.
•  Connect the audio generator to the channel input and set it to 1kHz 775mVRMS (0dB)
sinusoidal signal.
•  Place the temperature sensor between heatsink and the PTC (TH1).
•  Connect the CH1 scope GND clip to CN4 pin 1 (SGND terminal) and the probe tip to R50
side RL1 (PWR out), set it to 20V/div. 1mS/div.
•  Connect the CH2 probe tip to R58 side C28 and set its sensitivity at 0.2V/div.
•  Set the LEVEL potentiometer full clockwise.
•  The load resistor is disconnected.
•  The procedures that follow must be executed subsequently in the order speciﬁ ed.

Supply Check

•  Remove the transformer secondary fuses (located on SUPPLY board), set the Variac to
the nominal mains voltage, check with the Multimeter the AC supply voltages:
  F1-F2=71±2Vac
•  Re-set the Variac at zero voltage, turn off the ampliﬁ er and put the fuses back on its
holders.
•  Set up the Variac slowly monitoring the Outputs with the oscilloscope CH1 connected,
starts from 2/3 of nominal mains voltage it should display the sinusoidal input signal am-
pliﬁ ed with no distortions, if a distortion occur or the protection trips, turn off the ampliﬁ er
and check the AMPLIFIER board as suggested in the ADVICES section.
•  Finally verify the DC supplies on SUPPLY board:

CN4 pin 2 (+Vcc1)

=+50±2Vdc

CN5 pin 1-2 (-Vcc1)

=-50±2Vdc

CN4 pin 4

=+15±1Vdc

CN4 pin 5

=-15±1Vdc

•

If one or more voltages don’t correspond, check the rectiﬁ ers, capacitors and transformers

disconnecting them from circuitry, refer to schematics.

Channel Check

VOLTAGE AMPLIFIER TEST:

• Increase slowly the Variac. The channel output signals must be symmetrical respect the
GND without visible distortion and oscillation. If there is a distortion read the section ADVI-
CES.

CURRENT AMPLIFIER TEST:

• Connect

the

500W load on the output and repeat the test.

LIMITER CHECK:

• Increase the input signal of 10 dB and verify the output voltage and wave shape remain
constant.

BIAS ADJUSTMENT:

• With resistive load connected wait until the temperature reach 50°c.
• Set the generator level at zero, connect the Multimeter across the R50 and R53 resistors,
then adjust VR1 trimmer to read 5±0.1mVdc.

BANDWIDTH CHECK:

•

Switch alternatively the generator frequency to 100Hz and 10kHz, no level changes must

be detectable respect 1kHz.
• Switch the generator frequency to 30Hz and verify the output level decreases abruptly
respect to 1 KHz level.

OFFSET SENSOR CHECK:

• Set the Variac to zero voltage output, disconnect resistive load from the ampliﬁ er output,
connect temporarily (by means of a suitable conductor wire) CN4 pin 4 (+15Vdc) to R72
side RL1, the protection circuitry (Q14,15,16) detect the DC voltage and open the output
relay (RL1) within 3 seconds approx.
• Remove the connection, wait until the relay switch on and after some seconds repeat
the check with -15Vdc (available on CN4 pin 5), the protection circuitry must open the relay
again.

SIGNAL TO NOISE RATIO CHECK:

• Disconnect the audio generator and short the input (pin 1,2,3 of XLR socket shorted) the
output signal (noise) must be less than 1mV.

H150A H200A H200MA CHECKING & ADJUSTMENTS

The following adjustment and notes are relative to these models only.

Technical Specifications

Dimensions: .....................H150A (WxHxD) ................................... 340x460x285mm
.......................................H200A (WxHxD) ................................... 390x508x325mm
.......................................H200MA (WxHxD) ................................ 390x508x325mm
Weight: ............................H150A ................................................ 18.5Kg
.......................................H200A ................................................ 22Kg
.......................................H200MA .............................................. 20.5Kg
Power Requirements: .........(230Vac±10% 50Hz) ............................ 180VA
.......................................(115Vac±10% 50/60Hz) ....................... 180VA
Output Power*: .................(8

) ................................................... 136W

Max.Undistorted Out*: .......(8

) ................................................... 93Vpp

Sensitivity: .......................H150A (1W/1m) ................................... 92.5dB

SPL

.......................................H200A H200MA (1W/1m) ...................... 96.4dB

SPL

Max SPL: ..........................H150A (continuous) .............................. 114dB

SPL

.......................................H150A (peak) ...................................... 117dB

SPL

.......................................H200A H200MA (continuous) ................. 118dB

SPL

.......................................H200A H200MA (peak) .......................... 121dB

SPL

Frequency Response ..........H150A (ampliﬁ er+speaker) .................... 60Hz÷20KHz
.......................................H200A (ampliﬁ er+speaker) .................... 55Hz÷20KHz
.......................................(only ampliﬁ er -3dB)............................. 10Hz÷60KHz
Input Sensitivity: ...............(0dB) .................................................. 0.775V

RMS

Input Impedance: ..............(balanced) ........................................... 30K

.......................................(unbalanced) ....................................... 15K

Voltage Gain: .............................................................................. 33±1dB
IMD: ................................(SMPTE 60Hz/7KHz 4:1)........................ <0.1%
THD: ...............................(THD+N) ............................................. <0.1%
S/N Ratio: ........................(unweighted) ....................................... >100dB
*Note: measured with the limiter enabled.

Setup

and

200

Supply Check

•  Remove the transformer secondary fuses (located on SUPPLY board), set the Variac to
the nominal mains voltage, check with the Multimeter the AC supply voltages:
  F1-F2=90±2Vac
•  Re-set the Variac at zero voltage, turn off the ampliﬁ er and put the fuses back on its
holders.
•  Set up the Variac slowly monitoring the Outputs with the oscilloscope CH1 connected,
starts from 2/3 of nominal mains voltage it should display the sinusoidal input signal am-
pliﬁ ed with no distortions, if a distortion occur or the protection trips, turn off the ampliﬁ er
and check the AMPLIFIER board as suggested in the ADVICES section.
•  Finally verify the DC supplies on SUPPLY board:

CN4 pin 2 (+Vcc1)

=+63±2Vdc

CN5 pin 1-2 (-Vcc1)

=-63±2Vdc

CN4 pin 4

=+15±1Vdc

CN4 pin 5

=-15±1Vdc

•

If one or more voltages don’t correspond, check the rectiﬁ ers, capacitors and transformers

disconnecting them from circuitry, refer to schematics.

Channel Check

VOLTAGE AMPLIFIER TEST:

• Increase slowly the Variac. The channel output signals must be symmetrical respect the
GND without visible distortion and oscillation. If there is a distortion read the section ADVI-
CES.

CURRENT AMPLIFIER TEST:

• Connect

the

500W load on the output and repeat the test.

LIMITER CHECK:

• Increase the input signal of 10 dB and verify the output voltage and wave shape remain
constant.

BIAS ADJUSTMENT:

• With resistive load connected wait until the temperature reach 50°c.