Infinity Interlude Series User manual

Interlude Series
IL50 L/R
Powered Loudspeaker
Service Manual
Infinity Systems, Inc
250 Crossways Park Dr.
Woodbury, New York 797
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
3
Specifications
IL50 L/R Frequency Response: 32Hz - 22,000Hz (±3dB)
Recommended Amplifier Power Range 15-150 watts*
Subwoofer Amplifier Output: 250 watts (In to 8Ωfrom 20 Hz - 100Hz
with no more than 0.1% THD)
Sensitivity: 88dB (2.83V @ 1 meter)
Nominal Impedance: 8Ω
Crossover Frequencies: 150Hz; 2500Hz, 24dB/octave,
Low-Frequency Driver: 10" C.M.M.D., magnetically shielded
Mid-Bass Driver: 6-1/2” C.M.M.D., magnetically shielded
High-Frequency Driver: 1” C.M.M.D., magnetically shielded
Dimensions (H x W x D): 42" x 8-3/4" x 14-1/2"
(1067mm x 222mm x 368mm)
Weight: 60 lb (27kg)
* 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.

Detailed Specifications
IL50 L/R
4

IL50 L/R
5
Detailed Specifications (Cont.)

IL50 L/R
6
Controls and Connections (Cont.)

IL50 L/R
7
Controls and Connections

IL50 L/R
8
Controls and Connections (Cont.)

IL50 L/R
9
Controls and Connections (Cont.)

IL50 L/R
0
Operation/Bass Optimization S stemTM

IL50 L/R
Bass Optimization S stemTM (Cont.)
NOTE:It is important that you make the same adjustments to both loudspeakers.
Set the Bass Optimization System Bandwidth adjustments to a middle position (10 clicks from a
fully clockwise position) and set Level adjustments 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 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
slowly up and down until you have maximized the improvement.If you have really keen ears, you
can also have the Bandwidth controls 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
10
9
10
11

IL50 L/R
2
IL50 L/R Mechanical Parts List
* 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 - NM0825-01001 and above
IL50MPLL - NM0826-01001 and above
IL50CHL - NM0827-01001 and above
IL50BLKR - NM0828-01001 and above
IL50MPLR - NM0829-01001 and above
IL50CHR - NM0830-01001 and above
NOT FOR SALE

IL50 L/R
3
Exploded View
CABINET,
IL50
(NOT FOR SALE)
PORT TUBE,
336805-001
See page 12
SCREW, (10)
#8X.75" PB PPH BLK
900101-012
SCREW, (6)
#8X.75" PB PPH BLK
900101-012
SCREW, (2)
#8X.75" PB PPH BLK
900101-012
SCREW, (3)
#8X1" PB PPH BLK
900101-016
SCREW, (3)
#8X.75" PB PPH BLK
900101-012
SCREW, (4)
#6X.75" PB PPH BLK
903401-012 SCREW, (4)
6-19X.375 MS PPH BLK
905401-006
SCREW, (6)
#6X.75" PB PPH BLK
903401-012
SCREW, (4)
8-18X.5ZINK MS PPH BLK
905802-008
MID RANGE
TRANSDUCER,
335741-001
SCREW, (6)
#6X.75" PB PPH BLK
903401-012
GRILLE CUP, (6)
333249-003
GRILLE CUP, (3)
333249-003
GRILLE CUP, (7)
333249-003
BAFFLE,
336163-001, R
336163-002, L
VOLUME CONTROL
ASS'Y w/CABLE,
336250-001, R
336250-002, L
(ROTATED)
NETWORK,
336476-001
SPIKE (4),
331360-001
WOOFER,
335808-001
TRIM
RING,
336162-001
BUMP-ON (4),
330104-001
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
AMPLIFIER,
NOT FOR SALE
TWEETER,
335225-002
PEDESTAL,
336256-001
00269
GRILLE, WOOFER,
Part of Set - See
Upper Grille Options

IL50 L/R
4
Exploded View of Amplifier
00277
Rear Plastic Cover
930050
High Level
Binding Posts-JC0104
Power Cord, 15 FT.
WI0043
Feature PCB
Linear PCB
RABOS PCB
Power
Supply
PCB EMI Filter
PCB

IL50 L/R
5
Service Tips

Service Bulletin
Service Bulletin INF2002-02 - February 2002 Warranty labor rate: MINOR repair
To: All Infinity Service Centers
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.
IL50
16

Service Bulletin
Service Bulletin INF2001-04 Rev2 – May 2005 Warranty labor rate: MINOR repair
To: All Infinity Service Centers
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:
* 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).
IRF740 MOSFETS Q501, Q502
Infinity part# QM0055
D to S or S to D
G to S or S to G
D to G or G to D
Should measure >28K ohms*
Should measure >400 ohms
Should measure >28K ohms*
22 Ohm 0.6W Resistors R506, R503
Infinity part# RM0340
Should measure 22 ohms ±1%
IL120s
IL60 422 Ohm 1/4 watt Resistors R505, R502
Infinity part# RM0397
Should measure 422 ohms ±1%
IRF740 MOSFETS Q4, Q5
Infinity part# QM0055
D to S or S to D
G to S or S to G
D to G or G to D
Should measure >28K ohms*
Should measure >400 ohms
Should measure >28K ohms*
22 Ohm 0.6W Resistors R17, R20
Infinity part# RM0340
Should measure 22 ohms ±1%
IL50
IL100s 475 Ohm 1/4 watt Resistors R16, R19
Infinity part# RM0075
Should measure 475 ohms ±1%
IRF740 MOSFETS Q403,404,406,407
Infinity part# QM0055
D to S or S to D
G to S or S to G
D to G or G to D
Should measure >28K ohms*
Should measure >400 ohms
Should measure >28K ohms*
22 Ohm 0.6W Resistors R407,410,414,417
Infinity part# RM0340
Should measure 22 ohms ±1%
IM1.2s
IM4.1t
365 Ohm 1/4 watt Resistor
R408,411,415,418
Infinity part# RM0072
Should measure 365 ohms ±1%
IL50
17

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.
IL50
18

Service Bulletin
Service Bulletin INF2002-05 Rev5 - October 2005 Warranty labor rate: MAJOR repair
To: All Infinity Service Centers
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 A/R = As required
Infinity Part
Number
Ref.
Designator Description Qty Comment
QM0061 Q1 MOSFET, IRF540 TO220AB IR ONLY 1 As Needed
QM0055 Q4,Q5 MOSFET, IRF740 TO220AB IR ONLY 2 As Needed
TS0016 TUBING, #5 BLACK CUT TO .3 A/R
DR0091 D1 RECT, 15A 200V MUR1540 MOTOROLA ONLY 1 As Needed
810066
HEATSINK, FET CLIP, CLIP ON - NO
SCREW 2 Used with heatsink
810156 on U2,U3
810156 HEATSINK, LINEAR VOLTAGE REG 1
810157 HEATSINK, FET SEC BLACK 1 Replaces 810091
810158 HEATSINK, FET PRIMARY BLACK 1 Replaces 810092
810056 HEATSINK, FET CLIP .9 x .5 x .2 1 Use with Q1
MS0017
MISC, CERAMIC PLATE TO-220,
CERAMIC INSULATOR 0.025 5 Use with Q1,3,4,7,8
Thermal grease A/R
Use with Q1,3,4,5,7,8,
D1,D3
RM0002 R43 RES, MF 10K0 1/4W 1% 1 Replace
KS0027 50 DEGREE PTC THERMISTOR 1 Add
RTV DOW CORNING 747 OR
EQUIVALENT A/R
CE0145 C6 CAP, E 1000uF 100V 18 x 40 105C 1 To replace 85 deg.
part
TS0009 HEATSHRINK TUBING 1/16” DIA. A/R For KS0027 leads
CC0040 C11 CAP 0.0047µF 100v 10% 1 As Needed
RX0109 R1, R2 0.1 ΩRES MO, 2W 5% METAL FILM 2 As Needed
QB0014 Q6 MPSA92 PNP TO92 TRANS 1 As Needed
293-100K R22 100KΩ1/2W RES CF 5% 1 As Needed
KS0020 R26 SURGISTOR 10R 2A CL-110 (13S100L) 1 As Needed
RC0136 R30 RES, CF 160K 1/4W 5% 1 As Needed
RC0273 RES, ZERO OHM 1/4W 1
MS0005 SILPAD, .009" .3C/W TO3P 1
The repair procedure is to be executed in 3 phases.
1) POWER SUPPLY BOARD UPGRADE - THESE STEPS CORRESPOND WITH FIGURE 1
Step OPERATION
1. 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.
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.
3. D1 should be MUR1540 MOTOROLA ONLY, if not replace with DR0091, RECT, 15A 200V MUR1540
MOTOROLA
4.
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.
5. 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.
6. Parts Q4, Q5, D1, D3 must also have thermal grease between the devices and the heatsink.
7. Verify that C6 is a 105 deg.C part, if not replace with CAP, E 1000uF 100V 105C (CE0145)
8. 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
9. 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
10. Ensure that Q6 is MPS A92 PNP TO92 MPSA92TR. If not order Infinity Part # QB0014
11. 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
12. Ensure that R26 is SURGISTOR 10R 2A CL-110 (13S100L) If not order Infinity Part# KS0020
13. Ensure that R30 is 160K part (Color Code - Brown, Blue, Yellow, Gold), RES, CF 160K 1/4W 5%. If
not order Infinity Part# RC0136
14. Assemble the (new part) PRIMARY BLACK HEATSINK 810158 on the (2) FET(Q4 & Q5) side.
ENSURE THAT THE FETS ARE FLUSH AGAINST THE HEATSINK.
15. 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 OPERATION
Remove Linear Board from Amplifier Assembly
A Remove SILPADS under indicated location “A” in Figure 3 and thoroughly clean surface
with IPA or equivalent.
THESE STEPS CORRESPOND WITH FIGURE 2
1. Replace R43 with Infinity Part# RM0002, RES, MF 10K0 1/4W 1%
2. 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.
3.
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.
4. Important ! Cover both exposed thermistor leads with Shrink tubing (TS0009)
5. Solder RC0273 (RES, ZERO OHM 1/4W) to one lead of new Thermistor, as depicted.
6. Solder other lead of RC0273 to PCB location previously occupied by C1, as depicted.
7. Solder lifted lead of C1 to Thermistor as depicted.
THESE STEPS CORRESPOND WITH FIGURE 3
8. Insert (new part) MS0005, SILPAD, .009" .3C/W TO3P between new Heatsink (810156) and
both Regulators U2 and U3
9. Add (new part) HEATSINK, LINEAR VOLTAGE REG (810156)
B.
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.
10. 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
11. Secure THERMISTOR leads & C1 using RTV DOW CORNING 747 or equivalent as
depicted
20
IL50