McIntosh C24 Preamp Schematic.pdf

TUNER 75V O3 5.6 V 0103 R67 R 69 VWtWV- 100 K 330 K 0 Q15 5V Q101 LEFT OUTPUTS .22 10/100 r LEFT SPEAKER HEADPHONE RIGHT “ a SPEAKER L+R OUTPUT L+R VOLUME CONTROL RIGHT OUTPUTS 75 V I A R 100 I 18 K ALL VOLTAGES MEASURED UNDER FOLLOWING CONDITIONS- USE OF II MEGHOMS INPUT IMPEDANCE VTVM VOLTMETER INPUT VOLTAGE 117 V AC INPUT SELECTOR - AUX MODE SELECTOR - STEREO UNLESS OTHERWISE SPECIFIED ALL RESISTORS IN OHMS tW 10% LAST R R 108 LAST C C46 TRANSISTOR REPLACEMENT CHART MCINTOSH NO. EQUIVALENT NO Q 101_2N720_ Q 102_2N637_ Q 103 2 N 3390 SCHEMATIC, C 24 N0 J m n 10 shmBORroRr imc. Ir vH HilKV Willi i iiiii i mi SC 149-194 IB m MODEL NUMBER: C 24 MODIFICATION: Add four grounding springs to the shafts of the Volume, Balance, Bass and Treble controls. DESCRIPTION: Some controls have developed a noise when rotated. Adding the springs to ground the shafts prevents this condition. CAUTION: When adding the springs to the Bass and Treble control, be sure they make good contact. Make sure the spring is not too tight. If the springs are tight the clutch action of the controls will not function. PROCEDURE: Remove the front panel. Place the spring around the shaft and insert the ends of the spring into the control guide hole. See diagram.