Fisher CA 2100 Service Manual

Page 1

SERVICE MANUAL

FISHER
CA-2100

STEREO AMPLIFIER

WORLD LEADER IN HIGH QUALITY STEREO

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SPECIFICATIONS

POWER AMPLIFIER SECTION Maximum Input Signal (at 1 KHz 1% THD)
Minimum continuous RMS sine wave power per channel from 40 to Phone to RCDR 180mV
20,0004Hz with less than 0.8% total harmonic distortion into 4 ohm AUX, Tuner to SPKR 150mV
and 8 ohm loads. Tape 1. 2 to SPKFi 150mV
CONTROL AMPLIFlEFl SECTION Input Impedance Values (at 1KHz) K
Sensitivity for rated power (at 8 ohm, lKHzl Phone 50 ohm
AUX. Tuner 50K ohm
Phono 2.5mV T 1 2 50K h
AUX. Tuner 150mV ape ' D m
Tape 1.2 150mV Volume Control
Hum & Noise below rated power (Volume Max.) Tracking error 0 to 4OdB AA 3dB
Phono GEdB Attenuation at 50% rotation l7dB
Maximum attenuation 981218
AUX. Tuner SSdB
Bass Control Range (at 100Hz) thdB
Tape 1. 2 35dB 4,
Frequency Response Treble Control Range (at 10KHZI > -10dB
Phono RlAA 30H2715KH2 tldB Loudness Contour (at 30118 VoluflzgfienuationzgdB
AUX 20Hz-20KH2 :1dB 10KHZ +3d
Tape 1. 2 20Hz-20KH2 as Z 5
ADJUSTMENT OF THE MAIN AMP P.C. BOARD
' BEFORE ADJUSTMENT (BI IDLING CURRENT ADJUSTMENT
1. Disconnect the PRE OUT/MAIN lN connector. Adjust VR 03 NR 04) for an idling current of 35mA. Measure
2. After the power switch is turned ON, allow a few minutes before the voltage at both sides of R91 (94) resistor (0.47 ohms) and
making adjustment, to be sure of the rnOSt stable operation. adjust VR 03 (VR 04) to indicate 0.018Vi0.001 V.
3. Connect dummy load resistors (8 ohms) to the speaker terminals. Note: Polarity of Emitter of 023 (026) is (+).
4. Use a DC V.T.V.M. (Input impedance: More than 50K ohms/V) Mid-point is (-I.
(AIMlD-POINT POTENTIAL ADJUSTMENT ICI Repeat steps A and B for optimum results.
5 Set the voltage between the speaker terminal and ground Note: a. Turn the semi-fixed variable resistor slowly during
(Chassis) to OV:0.01 V with VR 01 NR 02). adjustment.

b. Be careful of the polarity of each measurement point.

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