JBL MPA1100 Скачать руководство пользователя страница 20

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Channel will not come out of muting: 

A.

If reducing Gain to zero does not release muting, the channel is defective or
overheated (see below). 

B.

If reducing Gain releases the muting, advance Gain slowly while watching the
LEVEL displays (in case there is an abnormal signal which could blow the
speakers). 

No sound is heard:

A.

Is the channel in muting? (PROTECT is bright, see below).

B.

If the LEVEL displays are active, (1) the speaker is open (blown), (2) there is an
open circuit in the speaker wiring, or (3) there is an open circuit in the internal
output wiring of the amplifier.  (Consult a JBL dealer for service.)

C.

If there is no LEVEL (SIGNAL PRESENT, -20dB, -30dB) or CLIP displays, (1)
there is no input signal, or (2) the ribbon cable to the input module may not be
seated well.

D.

If the CLIP display is bright or peaking with little or no LEVEL display, this
indicates shorted speaker line (especially if PROTECT starts flashing). 

Channel goes into muting (temp-protect LED is on):

A.

If flashing of the PROTECT display is visible, amplifier has muted due to
extreme overheating. Fan should be running at full speed, and unless ventila-
tion is blocked, operation should resume within one minute. 

B.

The amplifier will mute in response to extreme high frequency overdrive, and
output will not be restored until the frequency or level is lowered. Try turning
down the Gain control to release muting, and determine the source of abnormal
frequencies. 

C.

Muting which does not respond to either condition suggests DC shutdown or
other amplifier fault. 

Hum Problems:

A.

Ground lift of the signal is not available in these amplifiers due to the design
which utilizes grounded-collector transistor mounting to improve thermal effi-
ciency. Low-emission AC transformers are used, and balanced inputs afford
hum rejection. If hum persists despite the balanced inputs, check the tightness
of the rear panel screws which hold the input panel in place (two outer screws,
and two screws holding barrier strip). If the input wiring is near SCR (silicon
controlled rectifier) dimmers, transformer-isolated inputs may be necessary
because of the exceptionally high noise field voltages generated by SCRs. 

Troubleshooting

Содержание MPA1100

Страница 1: ...P r o f e s s i o n a l A m p l i f i e r Clip 10dB 20dB Signal Present Clip 10dB 20dB Signal Present Power Protect 1 CHANNEL 2 18 10 8 6 4 12 14 24 0 2 48 18 10 8 6 4 12 14 24 0 2 48 Clip 10dB 20dB...

Страница 2: ...HE RISK OF ELECTRIC SHOCK DO NOT REMOVE THE COVER NO USER SERVICEABLE PARTS INSIDE REFER SERVICING TO QUALIFIED SERVICE PERSONNEL VORSICHT UM DAS RISIKO EINES ELEKTRISCHEN SCHLAGES ZU VERMINDERN ABDEC...

Страница 3: ...peaker Outputs 5 Figure 5 Typical Unbalanced Connection 6 Figure 6 Portable Balanced System 6 Figure 7 Installed Balanced System 6 Figure 8 Ground Bus Connection 6 Figure 9 Jumper Positions for XLR Po...

Страница 4: ...ort within the rack must be used in portable applica tions Open Input Architecture Slots Provided with each MPA Series amplifier is a standard input module This module and the upper input cover panel...

Страница 5: ...6 7 13 23 22 23 22 25 29 24 27 28 26 30 31 31 25 29 24 27 28 26 30 31 31 Figure 2 Rear and Front Panel for 2 Space High Models MPA275 MPA400 MPA600 Figure 3 Rear and Front Panel for 3 Space High Mode...

Страница 6: ...ce is 20 kilohm balanced 10 kilohm unbalanced as is typical of JBL amplifiers The input jacks are located on a removable panel which has a toggle switch for 1 bridged mono 2 normal stereo or 3 paralle...

Страница 7: ...ld at the source with no connection to pin 1 at the amplifier If after wiring the input as shown above any hum or buzzing is present connect the GND terminals of all amplifiers together This bus shoul...

Страница 8: ...the rear panel 5 Install the input ribbon cable and remount the Standard Input Module securely To Parallel the Inputs 1 Locate the selector switch adjacent to the CHANNEL 1 input XLR connector and se...

Страница 9: ...MIN CH 2 CH 1 DUAL CHANNEL OUTPUT CONNECTOR STEREO 4 OHM MIN PER CH CONNECT ONE SPEAKER LOAD ONLY Use Either Binding Posts or Stereo Speakon but not both 2 2 1 1 BRIDGED MONO MODE CAUTION Output volt...

Страница 10: ...hese levels in perspective music played at one third average power will be in a state of constant clipping and this power level is about the greatest one can obtain without completely obliterating the...

Страница 11: ...1400 x 2 56 0 A 23 4 A 11 8 A 8 8 510 x 2 18 6 A 9 8A 4 8 A MPA750 4 4 760 x 2 30 0 A 14 8 A 6 8 A 0 8 A 2 2 1000 x 2 39 4 A 21 4 A 10 6 A 8 8 425 x 2 13 6 A 8 6 A 3 6 A MPA600 4 4 610 x 2 23 0 A 13 4...

Страница 12: ...A 2 2 1400 x 2 28 0 A 11 7 A 5 9 A 8 8 510 x 2 9 3 A 4 9A 2 4 A MPA750 4 4 760 x 2 15 0 A 7 4 A 3 4 A 0 4 A 2 2 1000 x 2 19 7 A 10 7 A 5 3 A 8 8 425 x 2 7 8 A 4 3 A 1 8 A MPA600 4 4 610 x 2 11 5 A 6 7...

Страница 13: ...proaches maximum tempera ture Illuminated steadily plus flashing during thermal muting Illuminated steadily during non thermal muting Typical Power Up Operation Power Down Behavior When the amplifier...

Страница 14: ...bnormal PROTECT may flash too CLIP flashing at full LEVEL display indicates the amp has reached full power clipping and the limiter is acting to prevent severe overdrive A steady CLIP glow after the f...

Страница 15: ...hose models rated at 2 ohms see Specifications the LEVEL 10 display should not be on more than about half the time with only occa sional clipping Protection Circuits The essence of high efficiency lig...

Страница 16: ...f 15 dB If this does not arrest the temperature rise in case of an output short or blocked ventilation the amplifier will finally enter full muting which causes full shutdown of the output bias circui...

Страница 17: ...oad grounding relay with internal fault fuses Complementary linear high efficiency outputs 3 step on MPA1100 2 step on MPA750 MPA600 MPA400 1 step on MPA275 100 120 220 240 Vac 50 60 Hz See Charts on...

Страница 18: ...720 650 700 750 500 550 600 350 375 400 225 250 275 900 1000 1100 480 510 550 400 425 450 275 290 300 180 190 200 740 770 800 700 760 825 550 610 675 400 425 450 275 300 400 1000 1100 1200 900 950 100...

Страница 19: ...1 THD 1 dB 50 Hz AC Power Mains 220 VAC 230 VAC 240 VAC 660 690 720 220 VAC 230 VAC 240 VAC 650 700 750 500 550 600 350 375 400 225 250 275 220 VAC 230 VAC 240 VAC 900 1000 1100 220 VAC 230 VAC 240 VA...

Страница 20: ...TECT display is visible amplifier has muted due to extreme overheating Fan should be running at full speed and unless ventila tion is blocked operation should resume within one minute B The amplifier...

Страница 21: ...speed 50 60 C Fan Speed rises gradually from slow to full 75 C PROTECT LED starts flashing 85 C PROTECT flash rate increases and CLIP starts to glow steadily The limiter will begin to reduce amplifie...

Страница 22: ...ty without prior authorization You may obtain that authorization by contacting the factory or repair facility directly Please ship amplifiers in original packing materials or equiva lent to prevent fu...

Страница 23: ...Part No TD 007500 OB PS137 2 A Harman International Company JBL Incorporated 8500 Balboa Boulevard Northridge California 91329USA...

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