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Interlude Series

IL50 L/R Powered Loudspeaker
Service Manual

Infinity Systems, Inc 250 Crossways Park Dr. Woodbury, New York 11797 REV10 10/2005

IL50
CONTENTS

SPECIFICATIONS ..............................................................3 DETAILED SPECIFICATIONS ..............................................4 CONTROLS and CONNECTIONS .........................................6 OPERATION......................................................................10 BASS OPTIMIZATION SYSTEM............................................10 MECHANICAL PARTS LIST.................................................12 EXPLODED VIEW .............................................................13 EXPLODED VIEW OF AMPLIFIER........................................14 SERVICE TIPS..................................................................15 SERVICE BULLETIN INF2002-02 .........................................16 SERVICE BULLETIN INF2001-04 .........................................17 SERVICE BULLETIN INF2002-05 .........................................19 TECH TIP INFTT2003-03.....................................................24 TEST SET UP PROCEDURE...............................................25 IL50 ADJUST BIAS PROCEDURE........................................26 PACKAGING ....................................................................27 PRINTED CIRCUIT BOARD DIAGRAMS................................28 ELECTRICAL PARTS LIST (120v).........................................34 INTEGRATED CIRCUIT DIAGRAMS ....................................40 HI-PASS CROSSOVER SCHEMATIC..........................................41 IL50 SCHEMATICS............................................................42

2

IL50 L/R Specifications
IL50 L/R Frequency Response: Recommended Amplifier Power Range Subwoofer Amplifier Output: 32Hz - 22,000Hz (±3dB) 15-150 watts* 250 watts (In to 8 from 20 Hz - 100Hz with no more than 0.1% THD) 88dB (2.83V @ 1 meter) 8 150Hz; 2500Hz, 24dB/octave, 10" C.M.M.D., magnetically shielded 6-1/2" C.M.M.D., magnetically shielded 1" C.M.M.D., magnetically shielded 42" x 8-3/4" x 14-1/2" (1067mm x 222mm x 368mm) 60 lb (27kg)

Sensitivity: Nominal Impedance: Crossover Frequencies: Low-Frequency Driver: Mid-Bass Driver: High-Frequency Driver: Dimensions (H x W x D):

Weight:

* The maximum recommended amplifier power rating will ensure proper system headroom to allow for occasional peaks. We do not recommend sustained operation at these maximum power levels.

3

IL50 L/R Detailed Specifications

4

IL50 L/R Detailed Specifications (Cont.)

5

IL50 L/R Controls and Connections (Cont.)

6

IL50 L/R Controls and Connections

7

IL50 L/R Controls and Connections (Cont.)

8

IL50 L/R Controls and Connections (Cont.)

9

IL50 L/R Operation/Bass Optimization SystemTM

10

IL50 L/R Bass Optimization SystemTM (Cont.)
NOTE:It is important that you make the same adjustments to both loudspeakers. Set the Bass Optimization System Bandwidth adjustments 11 to a middle position (10 clicks from a fully clockwise position) and set Level adjustments 10 for a ­6dB (8 clicks from a fully clockwise position). Then,while the music is playing,sit in your favorite chair and have somebody else slowly adjust the Frequency controls 9 from fully clockwise to fully counter-clockwise. At a certain frequency, you should hear the problem lessen and the overall bass performance improve. When you are satisfied that you have found the best frequency, have your assistant vary the Levels 10 slowly up and down until you have maximized the improvement.If you have really keen ears, you can also have the Bandwidth controls 11 adjusted for maximum benefit. While the Bass Optimization System allows the listener to fine-tune the bass response to sound best in a particular room,some listeners don't have the skill or desire to adjust their system by ear. In order to facilitate quicker and more accurate results, Infinity has developed an optional test and measurement kit that allows the user to perform a series of measurements and aids him/her in properly setting the Bass Optimization System controls. With the addition of this kit,the Bass Optimization System becomes truly room-adaptive. The kit consists of the following:a test CD, a sound-level meter that is specifically calibrated for low frequencies, and something we call a "Q-Finder, "a device to help find the width of the measured curve and, finally, a measurement template. It works as follows. The listener plays the tones from the test CD and records the relative output level of each test tone, using the sound-level meter, on the provided measurement template. After all the tones are complete, the template contains a response curve for the frequencies below 100Hz. The user simply notes the frequency of the largest bass peak,calculates the correct amount of attenuation,and uses the "Q-Finder" to determine the width of the curve. These three values are dialed into the Bass Optimization System controls located on the speaker.The entire process takes less than twenty minutes. If your dealer does not stock the Bass Optimization System test and measurement kit,you may purchase it directly from Infinity. U.S. residents can visit our Web site at www.infinitysystems.com or call 1-800-553-3332.Canadian residents should contact their dealer or call 1-800-567-3275. Ask for Infinity part number 335852-002.

11

IL50 L/R IL50 L/R Mechanical Parts List
NOT FOR SALE

* On 9/1/2000 a new replacement port tube was included with the IL50. Supplied part number reflects the new part. In addition, modified IL50 product w/ new port tube may be identified by the following serial number prefixes, which appears on the amplifier faceplate and the carton barcode label: IL50BLKL IL50MPLL IL50CHL IL50BLKR IL50MPLR IL50CHR NM0825-01001 NM0826-01001 NM0827-01001 NM0828-01001 NM0829-01001 NM0830-01001 and and and and and and above above above above above above

12

IL50 L/R Exploded View
SCREW, (4) #6X.75" PB PPH BLK 903401-012 SCREW, (4) 6-19X.375 MS PPH BLK 905401-006 VOLUME CONTROL ASS'Y w/CABLE, 336250-001, R 336250-002, L (ROTATED) MID RANGE TRANSDUCER, 335741-001 SCREW, (6) #6X.75" PB PPH BLK 903401-012

PORT TUBE, 336805-001 See page 12 CABINET, IL50 (NOT FOR SALE)

SCREW, (10) #8X.75" PB PPH BLK 900101-012

SCREW, (4) 8-18X.5ZINK MS PPH BLK 905802-008

TWEETER, 335225-002 BAFFLE, 336163-001, R 336163-002, L AMPLIFIER, NOT FOR SALE NETWORK, 336476-001 TRIM RING, 336162-001 GRILLE CUP, (3) 333249-003 GRILLE CUP, (7) 333249-003 SCREW, (6) #6X.75" PB PPH BLK 903401-012 GRILLE CUP, (6) 333249-003

WOOFER, 335808-001

SCREW, (3) #8X1" PB PPH BLK 900101-016

00269

GRILLE, BLACK, LEFT 335612-072 GRILLE, BLACK, RIGHT 335612-071 GRILLE, MIDNIGHT BLUE, LEFT 335612-052 GRILLE, MIDNIGHT BLUE, RIGHT 335612-051 GRILLE, RICH BURGUNDY, LEFT 335612-062 GRILLE, RICH BURGUNDY, RIGHT 335612-061 GRILLE, GRAY, LEFT 335612-042 GRILLE, GRAY, RIGHT 335612-041 PEDESTAL, 336256-001

SCREW, (3) #8X.75" PB PPH BLK 900101-012

GRILLE, WOOFER, Part of Set - See Upper Grille Options SPIKE (4), 331360-001

SCREW, (2) #8X.75" PB PPH BLK 900101-012 SCREW, (6) #8X.75" PB PPH BLK 900101-012 BUMP-ON (4), 330104-001

13

IL50 L/R Exploded View of Amplifier

High Level Binding Posts-JC0104

Feature PCB Linear PCB Rear Plastic Cover 930050

RABOS PCB

Power Supply PCB

EMI Filter PCB

Power Cord, 15 FT. WI0043

14

00277

IL50 L/R Service Tips

15

IL50

Service Bulletin
Service Bulletin INF2002-02 - February 2002 To: All Infinity Service Centers Warranty labor rate: MINOR repair Model: Interlude IL50, IL100s Subject: No Output In the event you receive an Interlude IL50 or IL100s subwoofer with the complaint: "There is no output, and the LED on the volume control does not light, red or green", check the items listed below: Check the 3A line fuse to make sure it's not open. If open, replace with a 3A MDL (.25 x 1.25) slo-blo fuse, Infinity part# 80126. Locate R22 in the power supply section, as shown below. If value of R22 is not 100k ohms ±5%, then replace R22 with a 1/2 Watt 100k ohm ±5%, resistor. 1. Remove the grille. Lay the subwoofer on its face on a padded surface, amplifier facing upwards. 2. Remove the 10 Phillips screws around the outer perimeter of the amplifier faceplate; remove the amplifier from the cabinet. 3. Remove two Phillips screws on the faceplate to remove the rear plastic cover; they are (1) the screw directly above the Bass Optimization switch and (1) to the left of the power cord receptacle; remove the amp cover. 4. Locate the power supply section and R22 from the illustrations below. R22 can be checked in-circuit and should be 100k ohms ±5%. If it is any other value, or open, replace with Infinity part# RC0082. 5. Reassemble the amplifier, rear cover, replace the amplifier in the cabinet and test the subwoofer.

16

IL50

Service Bulletin
Service Bulletin INF2001-04 Rev2 ­ May 2005 To: All Infinity Service Centers Warranty labor rate: MINOR repair Model: Interlude and Intermezzo IL50, IL60, IL100s, IL120s, IM1.2s, IM4.1t Subject: No Output In the event you receive an Interlude or Intermezzo loudspeaker with the complaint: "There is no output, and the LED on the volume control does not light, red or green", check the item listed below:
1) Check the line fuse to make sure it's not damaged. Replace if necessary IL50, IL100s 3A Infinity part# FS0022 IL60, IL120s 4A Infinity part# FS0026 IM1.2s, IM4.1t 6A Infinity part# FS0027

If the fuse is intact, or the unit still does not function, check the power supply portion of the amplifier circuit, described below: 2) Refer to the Exploded view page for detailed instructions on amplifer removal from the enclosure. 3) Remove all connectors and screws necessary to detach the Power Supply PCB from the main chassis heatsink. Squeeze the heads of the plastic standoffs with long-nosed pliers to detach the PCB from the heatsink. 4) Refer to the illustration on page 2. Check the DC resistance of following parts, in circuit, with a DMM: IRF740 MOSFETS Q501, Q502 Infinity part# QM0055 IL120s IL60 22 Ohm 0.6W Resistors R506, R503 Infinity part# RM0340 422 Ohm 1/4 watt Resistors R505, R502 Infinity part# RM0397 IRF740 MOSFETS Q4, Q5 Infinity part# QM0055 22 Ohm 0.6W Resistors R17, R20 Infinity part# RM0340 475 Ohm 1/4 watt Resistors R16, R19 Infinity part# RM0075 IRF740 MOSFETS Q403,404,406,407 Infinity part# QM0055 22 Ohm 0.6W Resistors R407,410,414,417 Infinity part# RM0340 365 Ohm 1/4 watt Resistor R408,411,415,418 Infinity part# RM0072 D to S or S to D Should measure >28K ohms* G to S or S to G Should measure >400 ohms D to G or G to D Should measure >28K ohms* Should measure 22 ohms ±1% Should measure 422 ohms ±1% D to S or S to D Should measure >28K ohms* G to S or S to G Should measure >400 ohms D to G or G to D Should measure >28K ohms* Should measure 22 ohms ±1% Should measure 475 ohms ±1% D to S or S to D Should measure >28K ohms* G to S or S to G Should measure >400 ohms D to G or G to D Should measure >28K ohms* Should measure 22 ohms ±1% Should measure 365 ohms ±1%

IL50 IL100s

IM1.2s IM4.1t

* The two transistor leads should be shorted together before these measurements are taken; the DMM leads will "charge" the circuit and the value may change, but should match the values above. Very low values that do not change indicate a shorted MOSFET.

5) Replace any defective parts above that show measured values lower than normal. 6) Reconnect J505 or J6 multicolor ribbon cable connector; remount the Power supply PCB; reconnect J501/502 or J4/J5 black/red Faston connectors. 7) All models except IM1.2S, IM4.1t: temporarily DO NOT connect the pair of black/red "CD±" leads on the linear PCB). Isolate the ends so they are not touching each other, or any conductive material. (For models IM1.2S, IM4.1t procedure is finished; replace amplifier).

17

IL50
8) Connect the subwoofer amplifier to an AC power source; turn the unit ON. Measure the DC voltage at the "CD±" wires; it should be 10-20 volts. 9) If it is 25 volts or greater, turn the amplifier OFF, disconnect from the power source, and replace: IL120S, IL60: Q504,Q507 IRF640 on the Power Supply PCB, Infinity part# QM0015. IL50, IL100s: Q1 IRF540 on the Power Supply PCB, Infinity part# QM0020. 10) If the voltage is normal, turn the amplifier OFF, disconnect from the power source, and reconnect the "CD±" leads. 11) Finish reassembling the amplifier, remount the heatsink, replace the amplifier in the cabinet and test the subwoofer.

18

IL50

Service Bulletin
Service Bulletin INF2002-05 Rev5 - October 2005 To: All Infinity Service Centers Warranty labor rate: MAJOR repair Model: Interlude IL50 Subject: Reliability Upgrade PURPOSE: Improve reliability of the IL50 amplifier; this procedure should be followed for every unit that has to be serviced, for any reason.

PLEASE READ ENTIRE PROCEDURE FIRST BEFORE ORDERING PARTS OR SERVICING THE AMPLIFIER. SOME PART REPLACEMENTS ARE AS NEEDED BASIS ONLY; SEE SHADED AREAS IN CHART BELOW. IR = Brand International Rectifier
Infinity Part Number QM0061 QM0055 TS0016 DR0091 810066 810156 810157 810158 810056 MS0017 Ref. Designator Q1 Q4,Q5 D1 Description MOSFET, IRF540 TO220AB IR ONLY MOSFET, IRF740 TO220AB IR ONLY TUBING, #5 BLACK CUT TO .3

A/R = As required
Qty 1 2 A/R 1 2 1 1 1 1 5 A/R 1 1 A/R 1 A/R 1 2 1 1 1 1 1 1 To replace 85 deg. part For KS0027 leads As Needed As Needed As Needed As Needed As Needed As Needed Comment As Needed As Needed As Needed Used with heatsink 810156 on U2,U3 Replaces 810091 Replaces 810092 Use with Q1 Use with Q1,3,4,7,8 Use with Q1,3,4,5,7,8, D1,D3 Replace Add

RECT, 15A 200V MUR1540 MOTOROLA ONLY
HEATSINK, FET CLIP, CLIP ON - NO SCREW HEATSINK, LINEAR VOLTAGE REG HEATSINK, FET SEC BLACK HEATSINK, FET PRIMARY BLACK HEATSINK, FET CLIP .9 x .5 x .2 MISC, CERAMIC PLATE TO-220, CERAMIC INSULATOR 0.025 Thermal grease

RM0002 KS0027

R43

RES, MF 10K0 1/4W 1% 50 DEGREE PTC THERMISTOR RTV DOW CORNING 747 OR EQUIVALENT CAP, E 1000uF 100V 18 x 40 105C HEATSHRINK TUBING 1/16" DIA. CAP 0.0047µF 100v 10% 0.1 RES MO, 2W 5% METAL FILM MPSA92 PNP TO92 TRANS 100K 1/2W RES CF 5% SURGISTOR 10R 2A CL-110 (13S100L) RES, CF 160K 1/4W 5% RES, ZERO OHM 1/4W SILPAD, .009" .3C/W TO3P

CE0145 TS0009 CC0040 RX0109 QB0014 293-100K KS0020 RC0136 RC0273 MS0005

C6 C11 R1, R2 Q6 R22 R26 R30

The repair procedure is to be executed in 3 phases.

1) POWER SUPPLY BOARD UPGRADE - THESE STEPS CORRESPOND WITH FIGURE 1
Step 1. OPERATION Q1 - This part must be IR only. Replace with QM0061, MOSFET, IRF540 TO220AB IR if needed. Use TUBING, #5 BLACK cut to .3 (TS0016) to set mounting height to 0.3".
19

IL50
2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. Q4,Q5. These parts must be IR ONLY. Replace with MOSFET, IRF740 TO220AB IR (QM0055). Q4 and Q5 must have black tubing on component leads: TUBING, #5 BLACK cut to .3 Inch in length (TS0016) or equivalent. D1 should be MUR1540 MOTOROLA ONLY, if not replace with DR0091, RECT, 15A 200V MUR1540 MOTOROLA Add a thin ceramic, CERAMIC PLATE TO-220, INSULATOR 0.025 THICK " (MS0017) behind Q1 with thermal grease on both sides of the ceramic. Ensure that grease covers the complete surface of ceramic on both sides. Remove SILPAD (MS0005 SILPAD, .009" .3C/W TO3P) behind D3 and thoroughly clean the adhesive film with an Alcohol blended cleaner such as IPA etc. Parts Q4, Q5, D1, D3 must also have thermal grease between the devices and the heatsink. Verify that C6 is a 105 deg.C part, if not replace with CAP, E 1000uF 100V 105C (CE0145) Ensure that C11 is 0.0047uF (4700PF 100V 10%). This part must be axial and not a radial part. If not order Infinity Part# CC0040 Ensure that R1, R2 are 0.1 ohm resistors (Color Code - Brown, Black, Silver and Gold) RES, MO 0.1 ohm 2W 5% Metal film, not wire wound. If not order Infinity Part# RX0109 Ensure that Q6 is MPS A92 PNP TO92 MPSA92TR. If not order Infinity Part # QB0014 Ensure that R22 is 100K, 1/2 watt part. (Color Code - Brown, Black, Yellow and Gold), RES, CF 100K 1/2W 5%. If not order Infinity Part# 293-100k Ensure that R26 is SURGISTOR 10R 2A CL-110 (13S100L) If not order Infinity Part# KS0020 Ensure that R30 is 160K part (Color Code - Brown, Blue, Yellow, Gold), RES, CF 160K 1/4W 5%. If not order Infinity Part# RC0136 Assemble the (new part) PRIMARY BLACK HEATSINK 810158 on the (2) FET(Q4 & Q5) side. ENSURE THAT THE FETS ARE FLUSH AGAINST THE HEATSINK. Assemble the 810157, HTSNK, FET SEC BLACK heat sink on side of three devices (Q1, D1, & D3) Install FET CLIP 810056 on Q1 (not shown in illustration)

2) LINEAR BOARD UPGRADE
Step A 1. 2. 3. 4. 5. 6. 7. 8. 9. B. 10. 11. OPERATION Remove Linear Board from Amplifier Assembly Remove SILPADS under indicated location "A" in Figure 3 and thoroughly clean surface with IPA or equivalent. THESE STEPS CORRESPOND WITH FIGURE 2 Replace R43 with Infinity Part# RM0002, RES, MF 10K0 1/4W 1% Locate, unsolder and lift a lead from C1 (CAP, E 2.2UF 50V BP 6X11 5MMLS) that is closest to the trim pot, see image. Mount new Thermistor (KS0027) at linear board mounting point as shown by removing the screw retaining the PCB bracket, inserting the Thermistor and rethreading the screw to hold down both the PCB and Thermistor, the tab "sandwiched" between the bracket and faceplate. Thermistor body should be flush with the faceplate. Important ! Cover both exposed thermistor leads with Shrink tubing (TS0009) Solder RC0273 (RES, ZERO OHM 1/4W) to one lead of new Thermistor, as depicted. Solder other lead of RC0273 to PCB location previously occupied by C1, as depicted. Solder lifted lead of C1 to Thermistor as depicted. THESE STEPS CORRESPOND WITH FIGURE 3 Insert (new part) MS0005, SILPAD, .009" .3C/W TO3P between new Heatsink (810156) and both Regulators U2 and U3 Add (new part) HEATSINK, LINEAR VOLTAGE REG (810156) Apply thermal grease to both surfaces of all (4) of the CERAMIC PLATE TO-220, CERAMIC INSULATOR 0.025" (MS0017), and sandwich between each power device and the faceplate. Replace the screws and clips; tighten. Secure Voltage regulators U2 and U3 to 810156, HEATSINK, LINEAR VOLTAGE REG using 810066, HEATSINK-FET CLIPS. These clip on and do not use screws Secure THERMISTOR leads & C1 using RTV DOW CORNING 747 or equivalent as depicted
20

IL50
3) IL50 ADJUST BIAS PROCEDURE
(Mandatory when any output MOSFET transistors Q3,4,7,8 are replaced)

Locate the Linear board assembly (PCB with the output transistors) Adjust R11 and R27 fully Counter Clockwise. See diagram below. Apply 120 VAC power to unit, Turn power switch ON. Verify LED illuminates on the front gain control dial unless you have disconnected the plug. Remove shorting plug on terminal J7 on Linear board, and insert current meter, set to the low mA range. 6. Verify initial current is less then 1 mA. 7. Adjust R11 Clockwise until current meter reads 5 mA plus the initial current from step #6. 8. Adjust R27 Clockwise until current meter now reads 10 mA plus the initial current from step #6. 9. Turn amplifier OFF. Disconnect AC power to unit. 10. Remove current meter; insert shorting plug back in terminal J7. 11. Replace cover (if present), wires if disconnected, and replace amplifier back into cabinet.

1. 2. 3. 4. 5.

Location for Bias pots

21

IL50
FIGURE 1 POWER SUPPLY BOARD UPGRADE

FIGURE 2 LINEAR BOARD UPGRADE (Most components absent for clarity)

3 7 4 2 5 5 6
1

22

IL50
FIGURE 3 LINEAR BOARD UPGRADE (cont'd)

8

11

9 10 A&B

Model

Identification 120V No Label Small White Rectangular label On Amp faceplate "Rev II 2002-XXX"

STATUS Needs Reliability Upgrade

ACTION Follow Steps Outlined Above

IL50

IL50

Modified by factory

NONE REQUIRED

23

IL50

TECH TIPS
Troubleshooting tips and solutions to common service problems
For models: IL50, IL100s, MSW-1, IL60, IL120s, IM2.6, IM3.5c TIP# INFTT2003-03

Intermezzo, Interlude and Modulus MSW-1 Power Supply Repair
Recommended for instances where the PCB has been damaged, for the above models only: 1) Change all MOSFETS, even for one device failure. 2) Clean and repair the PC board if required (See Tech Tip HCG2002-01 - Damaged Printed Circuit Boards). 3) Replace the Hybrid Bash Controller IC: U1 in models: IL50,IL100s,MSW-1,IM2.6,IM3.5c U501 in models: IL60, IL120s Infinity part # HC1011

FAILURE TO FOLLOW THE INSTRUCTIONS ABOVE MAY RESULT IN UNIT FAILURE WHEN THE AMPLIFIER IS POWERED UP

24

IL50 Test Set Up and Procedure

SYSTEM AURAL SWEEP TEST Equipment needed: · Function/signal generator/sweep generator · Integrated Amplifier · Multimeter · Speaker cables General Unit Function (UUT = Unit Under Test) 1. Remove the loudspeaker grille. 2. Switches on the amplifier faceplate: Sub Input to "Line Level" Low Pass Filter to OFF Bass Optimization system to OFF 3. From the signal generator, connect one line level (RCA) cable to the Subwoofer Line Level Input jack on the UUT. 4. On the front of the unit, turn the LEVEL control full counterclockwise (1). 5. Turn on generator, adjust to 50mV, 50 Hz. 6. Plug in UUT; turn the power switch ON. LED should be Red. Turn LEVEL control full clockwise (10) 7. LED should now be Green; immediate bass response should be heard and felt from port tube opening. 8. Turn off generator, turn VOLUME control fully counterclockwise, disconnect RCA cable. 9. Connect one pair of speaker cables to Speaker Level input terminal on UUT. Cables should be connected to an integrated amplifier fed by the signal generator. 10. Switch Sub Input on the amplifier faceplate to "Speaker". 11. Turn on generator and adjust so that speaker level input at the amplifier is 1.5V, 50 Hz. Turn LEVEL control full clockwise. 12. Green LED should light, immediate bass response should be heard and felt from the port tube opening. Sweep Function 1. Follow steps 10-12 above, using a sweep generator as a signal source. 2. Sweep generator from 20Hz to 300Hz. Listen to the cabinet and drivers for any rattles, clicks, buzzes or any other noises. If any unusual noises are heard, remove woofers and test. Driver Function 1. Remove woofer from cabinet; detach + and - wire clips. 2. Check DC resistance of woofer; it should be 3.4 ohms ±10% 3. Connect a pair of speaker cables to driver terminals. Cables should be connected to an integrated amplifier fed by a signal generator. Turn on generator and adjust so that speaker level output is 5.0V. 4. Sweep generator from 20Hz to 1kHz. Listen to driver for any rubbing, buzzing, or other unusual noises. 25

IL50
IL50 ADJUST BIAS PROCEDURE
(Mandatory when any output MOSFET transistors Q3,4,7,8 are replaced)

1. Amplifier should be unplugged and OFF. 2. Remove Amp assembly from cabinet; remove rear plastic cover if present. All wires exiting the cover can remain connected unless they will prevent you from removing the amplifier or accessing potentiometers on the Linear board PCB in the following steps. 3. Locate the Linear board assembly (PCB with the output transistors) 4. Adjust R11 and R27 fully Counter Clockwise. See diagram below. 5. Apply 120 VAC power to unit, Turn power switch ON. 6. Verify LED illuminates on the front gain control dial unless you have disconnected the plug. 7. Remove shorting plug on terminal J7 on Linear board, and insert current meter, set to the low mA range. 8. Verify initial current is less then 1 mA. 9. Adjust R11 Clockwise until current meter reads 5 mA + the initial current from step #8. 10. Adjust R27 Clockwise until current meter now reads 10 mA + the initial current from step #8. 11. Turn amplifier OFF. Disconnect AC power to unit. 12. Remove current meter; insert shorting plug back in terminal J7. 13. Replace cover (if present), wires if disconnected, and replace amplifier back into cabinet.

26

IL50

Packaging

27

IL50

EMI Filter PCB

28

IL50

Feature PCB

29

IL50 L/R Linear PCB

30

IL50

Volume Control PCB

31

IL50

Power Supply PCB

32

IL50

RABOS PCB

33

IL50 IL50 Electronic Parts List
Part# Reference Designator Qty Description

34

IL50 IL50 Electronic Parts List (Cont.)
Part# Reference Designator Qty Description

35

IL50 IL50 Electronic Parts List (Cont.)
Part# Reference Designator Qty Description

36

IL50 IL50 Electronic Parts List (Cont.)
Part# Reference Designator Qty Description

Change R22 to 100K ohm See Page 16

37

IL50 IL50 Electronic Parts List (Cont.)
Part# Reference Designator Qty Description

38

IL50 IL50 Electronic Parts List (Cont.)
Part# Reference Designator Qty Description

39

IL50

Integrated Circuit Diagrams

40

IL50s

Crossover Network Schematic
C3 128uF 100V C1 470uF 100V

L1 1.8mH

L2 0.30mH R1 10ohm 10w

+INPUT

WHT

+

250

MID C2 10uF 100V

-INPUT

WHT/BLK

205

L4 0.075mH

R3 0.5ohm 10w

C4 2.4uF 100V

C5 20uF 100V

R2 1.80ohm 10w

YEL

+ 187

L3 0.22mH HF

00323

YEL/BLK

110

41 38

Change R22 to 100K ohm - See Page 16

42

IL50

43

IL50

44

IL50

45

46

IL50

47