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CX Series
Power Supply and Voltage Rail Balancing
(Uneven rails and power supply problems)
Symptoms:
-
Current limiting wrong
l
Current limiting too high into a short
. IC rail too high into a short
-
Current limiting too low into a short
l
Uneven voltage rails
Possible Causes:
l
CURRENT LIMITING WRONG
Current limits should remain high down to 2 ohms, and collapse to a lower value for short
circuits. This is caused by the IC rails going from normal 14 - 1.5 volts to about 5-6 volts.
Current limit trimmers TR502 & TR503 permits adjustment of each channel to a specified range.
See Test & Calibration Procedures for correct adjustment of the current limiting.
l
CURRENT LIMITING TOO HIGH INTO SHORT
(I
C
ra
il
check norma
l
5-6 vo
lt
s)
1. Reversed or shorted 4.7V zeners D511, D514. (CX4/T) D503, D506.
2. Shorted bias diode D505, D506 (also shows severe crossover). (CX4/T) D504, D505.
l
IC RAIL TOO HIGH INTO SHORT
1. Check op amp (weak output current).
2. Clip LED LD103 open, clip circuit parts R544 high or missing. (CX4/T) LD
1
, LD3, R511.
3.
D101/D102/D103/D104
open. (CX4/T) BR500.
l
CURRENT LIMITING TOO LOW INTO SHORT AND 2 OHM LOAD
1. Bias resistor R512, R522 high.
2, Very low gain driver transistors.
3, Missing connection or open emitter resistors in some of the paralleled output transistors.
.
CURRENT LIMITING TOO LOW INTO SHORT ONLY
(OK into norma
l loads)
1.
3.9
or 4.7V zeners high (7.5V or 15V).
2. Clip LED LD103 shorted, clip circuit pans R544 low. (CX4/T) LD
1
, LD3, R511.
3.
D101/D102/D103/D104
shorted. (CX4/T) BR500.
l
OK INTO SHORT BUT LOW INTO 2 OHMS:
(
U
sua
ll y
on one side on
l
y)
1, IC RAIL LOW: Check replenishing resistor R548 and diodes D519, D.520. (CX4/T) D509,
D511, R518.
2. IC RAIL OK: (until clipping starts) usually indicates low output section gain caused by weak
driver, open output devices, or open emitter resistors. Also check value of driver emitter
resistors R501, R502. (CX4/T) R516, R517.
UNBALANCED RAIL VOLTAGES:
1. Shorted
Q
503, Q504.
2. Defective U501, U502.
3. Open R506, R505.
4. Open D514, D511. (CX4IT) D503, D506.
21
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 ...