KENWOOD KAC-929 free download

File name KAC-929 Service Manual.pdf

POWER AMPLIFIER KAC-929 SERVICE MANUAL © 2001-3 PRINTED IN KOREA B51-7768-00 (K) 3380 STEREO/BRIDGEABLE AMPLIFIER KAC-929 MAXIMUM POWER POWER IN FUSE(30Ax2) BATT. GND SPEAKER P.CON OUTPUT BRIDGED LEFT RIGHT 30 30 POWER AMPLIFIER SCREW SET (N99-1587-05) ACCESSORY (W01-1516-05) CONNECTING CORD ASSY (E30-4950-05) KAC-929 2 SPK L IC1 L ISOLATION AMPLIFIER INPUT SENS. (L) IC2 B.BOOST IC3 V IC1 R ISOLATION AMPLIFIER SPK R SW1 OPERATION ST/MONO Q5-8,29-33 DC DETECTOR OVER LOAD DETECTOR Q23,25-28 P.CON CIRCUIT Q24 OVER VOLTAGE CIRCUIT THERMAL PROTECTION P.C. BASS BOOST SW2 OFF/+6/+12 INPUT SENS. (R) IC2 B.BOOST SW3 EXPANDER INVERTER SW4 MIXER IC3 LOW PASS LPF ON/OFF SW3 IC4 IC3 EXPANDER INVERTER SW4 EXP. ON/OFF IC3 BUFFER Q4 MUTE Q102,104,106, 108,110,112 DIFFERENTIAL STAGE Q114,116,118,120, 122,124,126,128 B-CLASS STAGE SPK. OUTPUT BUFFER Q3 MUTE Q101,103,105, 107,109,111 DIFFERENTIAL STAGE Q113,115,117,119, 121,123,125,127 B-CLASS STAGE SPK. OUTPUT BLOCK DIAGRAM Q1,2 V AVR IC5 Q11-22 DC/DC CONVERTER BATTERY KAC-929 CIRCUIT DESCRIPTION [Expander Circuit] The expander circuit has been designed to expand the range of audio. Specifically, it inputs a signal with variation over 10 dB and outputs a signal with variation over 20 dB. In other words, the expander circuit can make loud sound louder and small sound smaller. Its characteristic is as shown in Figure 1, which shows its characteristic (B) in comparison with the characteristic of an ordinary amp (A). Figure 2 shows the characteristics of the expander amp used in this set. It shows that the effect described above is applied in the same way all over the bandwidth 0dB=24.5V (dB) 0 150W (4) 6.5dB 5.3dB (4 150W) (dB) OUTPUT LEVEL -10 15W 3.2dB +10 OUTPUT LEVEL 0 (A) (C) 2.1dB -20 1.5W -10 (B) -20 1.1dB 0.7dB -30 0.15W -25 -30 6.3mV -15 -20 20mV -10 -7 -5 63mV 0 (dB) 200mV -20 -10 0 INPUT LEVEL +10 (dB) INPUT LEVEL Fig.2 Fig.1 (A) Characteristic of ordinary amp (B) Characteristic of expander (C) Characteristic of expander amp used in the set Appendix IC4 block diagram is as shown in Figure 3. The point in incorporating an expander circuit in this set is to make the audio more powerful, with punch in it. The expander amp used in the set outputs similar audio to ordinary amp when the input level is low, while it can provide powerful audio with punch when the input level is above a certain level. THD TRIM R3 INVERTER IN G IN R2 20K VARIABLE GAIN R4 30K R3 20K VREF 1.8V OUTPUT RECT IN R1 10K RECTIFIER RECT CAP Fig.3 3 KAC-929 ADJUSTMENT No. ITEM INPUT SETTINGS OUTPUT SETTINGS RECEIVER SETTINGS ALIGNMENT ALIGN POINTS FOR FIG. Connect a cassette receiver or CD receiver. Connect a DC voltmeter between CN2 VOLUME : 0 (L/R) and J2 (SP.OUT, L+/R-) VR3 (L ch) VR4 (R ch) (X09-) 1 IDEL CURRENT - 2.5mV (a) (a)2.5mV VR3(Lch) DC Voltmeter Lch CN2 Rch VR4(Rch) L SP. OUT R (a)2.5mV DC Voltmeter 4 A B C D E F G H I J PC BOARD (Component side view