Shure SR105 Service Manual

SR105 Power Amplifier OPERATION AND SERVICE MANUAL Manufactured by SHURE BROTHERS INC. 222 Hartrey Avenue Evanston, Illinois 60204 U.S.A. WARNING To

MOUNTING AND VENTILATION The SR105 Power Amplifier is designed for rack-mount- ing in a standard 19-inch (483 mm) audio equipment cabinet rack and i

FIGURE 4. SR105 POWER AMPLIFIER BLOCK DIAGRAM METER RECTIFIER In applications where the Amplifier is located at a con- siderable distance from the

FIGURE 5. INPUT CONNECTIONS @ UNBALANCED PARALLELED MIXER- PREAMPLIFIER POWER AMPLIFIER 0 I I I I I \/ \A 0 UNBALANCED PARALLELED HIGH-IMPEDANCE INP

2 3 4 5 678910 20 30 40 LOAD IMPEDANCE (OHMS) FIGURE 6. TYPICAL OUTPUT POWER VS. LOAD IMPEDANCE FROM 2 OHMS TO 32 OHMS I1 KHz. 2% TOTAL HARMO

AMPLIFIER-TO-SPEAKER DISTANCE (FEET1 200 400 600 800 1000 1200 36 - 32 0) i 28 Y 2 24 Y 0 1 20 P 3 16 L J I2 0 8 4 0 50 100 1% 200 250 300

dance may be calculated by the formula: 1 1 1 1 -=- f-+- . . . . etc. ZT ZI 22 Z, where ZT is the total impedance, Z, is the impedance of the first

Meter Reading Output Power 100% 1 X 86.7% 3/4X 70.7% 1 /2X 50 % 1 /4X 33.3% 1/10X 10% 1/1oox In most applications, the VOLUME Control (2) set

duce approximately 28.3 volts at the DIRECT OUTPUT terminals (8,9), or 70 volts at the 70V OUTPUT terminals (11) when the 70-volt input li

SR105 Power Amplifier SERVICE INSTRUCTIONS AMPLIFIER SERVICE (See Guarantee) The SR105 Power Amplifier uses components of the high- est quality, ope

R39 R40 Dl2 R36 T2 C14 C15 R3 1 Q8 R35 Q7 R43 PL2 MI PL3 (XPL2) (XPL3) Y SRIOSA MODEL ONLY FIGURE 13. SR105 POWER AMPLIFIER TOP VIEW, CO

SR105 Power Amplifier SPECIFICATIONS The following specifications apply to both SR105A and SR105B Power Amplifiers except where noted. The SR105A Pow

Main Circuit Board SMALL SIGNAL AND PREDRIVER TRANSISTORS Transistors Q1 through Q6, Q13, Q14, and Q201 through Q203 are mounted on printed ci

OUTPUT TRANSISTORS Output transistors Q9 through Q12 (Figure 13, Page 13) are located on the black, finned heat sinks. The replace- ment procedure

11 TOOLS /I Description SR105B AMPLIFIER PARTS Pliers, Diagonal, or Wire Stripper *'Four machine screws presently securing rear-panel 70-Volt C

in the space exposed by removal of the cover using four 6-32 x 3h1' Phillips head machine screws. Be sure to orient the screw contacts on the

S 4 OFF JI-J2 e TS2 - - GROMMET x J e 3 d m WHT a FILTER &- + CIRCUIT t BOARD TU 1 YEL / BLK H& RED a J MAIN CIRCUIT BOARD R4 1 VOLUME FIGURE

REPLACEMENT PARTS FOR SR105 POWER AMPLIFIER 04, D5 I - I - 1 86A415 1 Diode,Silicon, Computer, 75V - Reference Designation Q8 Q9-Q12 R35-R40 R41

REPLACEMENT PARTS FOR SR105 POWER AMPLIFIER Reference Designation I RKC9 1 4 1 86A349 / Transistor. Silicon. NPN Replacement Kit Consists Of: Kit

FIGURE 18. MAIN CIRCUIT BOARD PARTS LOCATION DIAGRAM 2038-21525-2 FIGURE 19. FILTER CIRCUIT BOARD PARTS LOCATION DIAGRAM

SR105 Power Amplifier NOTES TO CIRCUIT DIAGRAM GENERAL Shure part numbers are not shown in the Parts List accompanying the Circuit Diagra

SR105 Power Amplifier SPECIFICATIONS (Curves shown are typical) FREQUENCY (Hz1 OUTPUT POWER (WATTS) TOTAL HARMONIC DISTORTION VS. OUTPUT POWER

LINE LEVEL INPUTS 120 VAC 50160 H r NOTE I: DIFFERENCES BETWEEN SRIOSA AND SR105B: "STRAIGHT- THROUGH" WIRING SHOWS SRlOSB CIRCUITS

SR105 Power Amplifier CONDENSED OPERATING INSTRUCTIONS DIRECT SPEAKER OUTPUT (MODELS SRlOSA and SRlOSBI CONSTANT VOLTAGE 70-VOLT SPEAKER OUTPUT (MO

The Amplifier shall have built-in circuitry to protect the Amplifier from open circuit, short circuit, or mismatched output loads, by using

SR105 Power Amplifier TABLE OF CONTENTS Section Page ... SPECIFICATIONS ii DESCRIPTION ...

SR105 Power Amplifier DESCRIPTION (Shown in A105A Carrying Case) The Shure SR105 Power Amplifier is a high-power ampli- fier designed for sound rei

FIGURE 1. SR105 POWER AMPLIFIER FRONT PANEL FIGURE 2. SR105 POWER AMPLIFIER REAR PANEL (SR105A MODEL SHOWN)

SR105 Power Amplifier OPERATING INSTRUCTIONS FUNCTIONAL IDENTIFICATION (Refer to Figures 1 and 2, Page 2). 1. OUTPUT VOLTAGE Meter - lndicates A