![QSC CX Series Скачать руководство пользователя страница 24](http://html1.mh-extra.com/html/qsc/cx-series/cx-series_service-manual_767404024.webp)
CX Series
5. Replace LD501 if voltage is less than 1.5V
l
SHUTS OFF UNDER SIGNAL
1. C517 missing, defective, or much too small
l
DC FAULT WITHOUT CURRENT DRAW
In most cases, shorts in the output circuit will cause current draw, but certain shorts will only cause DC
offset in the output. In both cases, measure all the voltages, and look for abnormal values to help trace
the fault, which can be a solder or component short (zero volts), reversed zener or diode (0.6V),
reversed electrolytic (several volts), or wrong value parts (abnormal voltage). Look at the following
points in the circuit.
I.
Shorted IC rails.
2. Blown D521, D522 give zero volts on the IC rail.
3, VR502, VR503 turned all the way off or way too low in value.
4. Collector-base short on the driver (rare without further damage)
5 Sometimes IC forces the rest of the circuit into DC due to shorts in the feedback network,
etc. To check this remove IC, check for +/-15V, and see if adjusting current limit trimmer
VR502, VR503 will produce a zero volt output (there will be no signal, of course). If so,
output stage is probably OK, look for problems in the IC, or its associated parts.
6. Defective/reversed IC (pull and check voltage)
l
FAN DOESN’T WORK:
1. Always operate at high speed: check shorted fan thermal switch. (on the heatsink under the
main PCB).
2. Always operate at low speed: check defective fan thermal switch.
3. Doesn’t operate: check open R902 on the AC PCB and intermittent fan cable connectors.
Faults with Signal Present
(The amplifier passes a signal but is not running correctly)
Symptoms:
-
Output power “breaking up”
l
-
Ringing’ sound with no input to amplifier
-
Output collapses into a 8, 4, or 2 ohm load
-
Voltage rails ok without signal
-
Amplifier gets too hot without load
-
One channel clips prematurely
-
Gain wrong
-
Poor Frequency Response
l
Step Circuit Problems
Possible Causes:
l
OUTPUT POWER “BREAKING UP”
(Output
distorted
1. R523, ,524,
526,
527 open (CX4/T) R520.
2. C513, C514 open. (CX4/T) C515.
3. Check for continuity between speaker ground, input ground and ac ground.
4. R501, R502, R543 open. (CX4/T) R516, R517.
5, Current limits out of adjustment.
Содержание CX Series
Страница 1: ...CX Series CX4 CX12 ...
Страница 2: ...CX Series CX4T CX1 2T ...
Страница 4: ......
Страница 6: ......
Страница 49: ...43 ...
Страница 50: ... CX Series 44 ...
Страница 51: ......
Страница 52: ...1 CX Series a 46 ...
Страница 53: ...1 I v 47 ...
Страница 54: ...CX Series 4a ...
Страница 55: ...CX Series ...
Страница 56: ...CX Series _ _____ i 50 ...
Страница 57: ... a C X S e r i e s t ...
Страница 59: ...CX Series ...
Страница 60: ...CX Series ...
Страница 61: ...H 5 5 ...
Страница 62: ...IWOHS A021 V X3 WVki3VlO ONMM xv LOmoo ix n3m osNvnl ...
Страница 64: ...I I oml ION om 104 I I INI I II kla 6waca SKDNNXXi3lM Nld Ol Nld IUM 3lm M36aRl6al mlm tl ...
Страница 65: ...CX Series 59 ...
Страница 66: ...CX Series 60 ...
Страница 67: ...CX Series i r ...
Страница 68: ...I I ____ d 62 ...
Страница 70: ...CX Series r 0 _________ a 64 ...
Страница 73: ... f 6 7 ...
Страница 74: ...L I CX Series 68 ...
Страница 75: ...1 I I 6 9 ...
Страница 80: ......
Страница 81: ......
Страница 82: ......
Страница 83: ......
Страница 84: ......
Страница 85: ......
Страница 86: ......
Страница 87: ...CX4 4T PCB Assemblies Component Side ...
Страница 88: ...C X 4 4 T P C B A s s e m b l i e s S o l d e r S i d e ...
Страница 90: ...CX6 6l 8 CXl2 12T Main Display Input PCB Assy Solder Side C 000944 00 REV A ...