JBL 6233 Manual

JBL
6233
INSTALLATION
AND SERVICE
MANUAL

Owner's Instructions
ArchitecturalSpecifications
The amplifiershallhavetwochannels,eachcapable
ofproducingan output of300W continuoussinewave
into a 4 Ci loadand200W continuoussinewave into
an 8 O load from 20Hzto20kHzat less than0.05%
THD. Full output shallbeachievedbyan input ofnot
morethan0.8V perchannel.Thepowersupplyshall
betheinvertertype.
Rise time shallbenomorethan5 /js into a 4 O load
or3 jdS into an8 O loadandtheslewrateshallbeat
least 20V/jus.
Humandnoiseshallbeatleast100OSbeiuw full
rated output, measured with 20kHzequivalent
bandwidth, input shorted.Nospuriousoscillationshall
bepresent with anycombinationofgroundedoropen
input connections.
The programinputsshalleachbeprovided with
a sockettoaccommodatea matching/bridging
transformer.
The amplifiershallbeequipped with protection
circuits that preventdamageduetooverload,short
circuitor excessive temperature rise. Itshallmeetall
performancespecificationsinambienttemperatures
upto50°C (122°F).A thermalsensingdeviceshall
beprovidedforeachchannel.Ifonechannelenters
theprotectmode,theotherchannelshallremain
unaffected.
Whenthermallyoverloaded,thedeactivatedchannel
shall automaticallyresumeoperationwhena safe
operatingtemperatureisreached.
Each amplifierchannelshallbecapableofbeing
overdriven from 10Hzto20kHzbyatleast10times
itsrated input voltage with thevolume control inthe
maximumgainposition.Thisoverdrive condition shall
notdamagetheamplifier.Theamplifiershallbe
capable ofsustained full rated output into a 4 O or
8 O loadat20kHzforatleastonehour without
malfunctioningorenteringtheprotectmode.
The amplifiershallhavefiveindicatorlightsper
channel forvisually monitoring output. Thelightsshall
becomeilluminatedinsequenceashigher output
levels arereached.Thedisplayshallindicatetrueclip-
ping levelregardlessofchangesinAClinevoltage.
Amplifierconstructionshallbemodular, permitting
completereplacementofeachchannelbythesubsti-
tution ofa replacementmodule.
The amplifiershalloperateona powersourceof
100 -120V ACor200- 240V AC,50/60Hz.Theperfor-
mance specificationsshallbelistedunder PRODUCT
SPECIFICATIONS andbemetorexceeded.
Product Specifications
Characteristic
Performance Supplemental
Power Gam 70dB
IfipUl ScfiSlt'V ny
\J . i i V
Fcr fu!l output
po,,\er
O'JiO'jt
300W 4 Q
ConLnoOoS sine vvave
200W 8 O both
channels driven
700W 8 Q
Continuous sine wave
400W 16O both
channels bridged
THD
2QJ4zto 20kHz
Both channels driven
- <0.05°b
atratedoutput
IM
s,0 05%
SMPTE Standard
Rise Time
5 |<sor less
Into4 Q
3^s~nr less Into8 O
Slew Rate
- o n \ / /
^-C\J V / /iO
Load Impedance 4n Minimum
8a Minimuminbridged
configuration
Damping Factor
40 Minimum(4O)
S/N
'100dBorbetter
Reference ratedoutput
Frequency Response
±0 5dB,20Hz~20kHz
PowerSupply
Line Voltage 120V normaland240V normal
switch selectable
Line Frequency
50or60Hz
Power Consumption 180W
Quiescent
920W
33%, both channels
driven
1450W
Full power,both
channels driven
Environmental
Operating Temperature50°C(122°F) Maximum
Physical
CHARACTERISTIC
INFORMATION
Overall Dimensions
133 mm x 483mm x 465mm
(including controls) (5.25"x19"x18.3125")
Mounting
3 EIAstandard rack spaces
DepthBehind Panel
445mm(17.5")
Panel Finish
Baked enamel,darkgray
NetWeight 15.7kg(34.5lb)
Accessories
5195 Matching/bridgingtransformerfor15kObridgingor600O
matching, oneper channel.
Note1.20kHzequivalentbandwidth.
Installation
The 6233issuitableforeitherrack mounting inthree
EIA standardrack spaces without additionalbracing,
with chassis slides(notprovided)orforcounter-top
placement.A full setof mounting hardwareforallbut
chassis slide mounting ispacked with each unit. All
externalconnectionsaremadeontherear chassis,
Figure 2.Total depth necessaryto mount the unit ina
rack is508mm(20inches).Thisallows room forair
circulation,powercordandconnections.

Indicators,ControlsandConnections
Figure2 showsthe front andrearpanelofthe6233
FIGURE 2
FRONT VIEW
Front Pane!
Pl|0t Lgpnn Indicatesapplicationofprimarypower.
Power Switch' Appliesprimarypower.
Protection Mode indicators; Indicatesabnormalthermal
condition
andshutdownof output signal.
Channel GamControl: Controls
input sensitivity.
AirFilter:
Prevents dustparticles from entering
unit.
Rear Panel
Output Terminals:
uu9^ iii!(JCUSIiceO i i 111111M uni pci
cnannel(duai-channeloperation;or
8O minimum (budgedoperation).
Input Terminals:
XLR connector with input impedance
of20kO(directtovolumecontrol),
of15kOor600O (balanced input
with optional matching/bridging
transformer))
GroundTerminal: Requiredtoorevenieiertricsnock
ufmSr\i SuppreSSiOn SyMtnii.
AirExhaust; Circulatedair
from unit.

Counter-top placement-Turn the unit upsidedown
qpH fQnrovn +h ° foijf
cTe\A/Q
from thf3 bottom cov^ras
indicatedinFigure1.Installthefourrubberfeetusing
thefour6-32x%,! screws.
NOTE: Operationofthe6233 sitting ona flatsurface
without theabovefeetwillresultin excessive fan
noise duetovibrationsoftheinternalcomponents
against the bottom cover.
The remainingcover screws shouldbereplaced with
6-32x 100°countersink screws only.
NOTE: Certainscrewpositionsdonothaveclearance
forlonger screws.
Rack-mounting using chassis slides- Threaded
mounting holesareincorporated into the6233 chassis
foruse with CHASSIS TRACK C-300-B-120 chassis
slides. These slidesoffer easy, convenient access to
enclosed racks from the front ofthecabinet.
CAUTION: Ifthe6233istobeshippedina rack
mountcabinet, chassis slidesarerecommendedin
ordertopreventdamagetothe front paneland
chassis duringtransit.
OperatingTemperature
The 6233iscooledbyairdrawninatthe front and
blownout through thebackofthe unit. Adequate
clearance mustbeprovidedatthebacktoallowfor
adequateheatdissipation.
CAUTION: Donotblockorrestricttheair flow from
theventilationholesinthecabinet.
A numberofthermalswitchesinthe6233provide
thermalprotectionanddualaxialfanspeedcontrolif
theinternaltemperatureexceedsa safeoperatinglevel
The air filter shouldbevisuallycheckedeveryfew
weeks andcleanedif dirty. Morefrequentinspections
are requiredundersevereoperatingconditions.
The following procedureissuggestedforcleaning
thp qir filter:
1. Removethe filter by pulling the filter frameand
filter away from the front panel.
2. Flush theloose dirt from the filter with a streamof
warmwater.
3. Place the filter ina solutionof mild detergentand
warmwaterandletsoakforseveralminutes.
4. Squeezethe filter towashoutthe dirt remaining.
5.Rinse the filter incleanwaterandletdry.
6 Re-installthe filter intheframeandinstallthe filter/
frametotheamplifier
The maximumambientoperatingtemperatureofthe
6233 is50°C(122°F).
NOTE: Operationathigherambienttemperatures
will limit themaximumcontinuouspoweravailable.
InputConnections
The 6233isshipped from JBLwiredforanunbalanced
input impedanceof20kO.
Figure 3 showstheproperwaytowiretheXLR
connectorforanunbalanced input.
OutputConnections
Outputconnectionsarevia5-way binding posts with
19 mm(075inch)centers.
Cleaning
To cleanthe front panelofthe6233,useonlya mild
soap andwarmwatersolution.
WARNING:Theuseofacetone,methyl-ethylketone
(MEK) oranysimilarproductwilldamagepanel
plastic components.
Remove
SHIELD-
-HOT
FIGURE 3
NOTE: Toavoidground loop problems,Pin1 ofthe
XLR connectorshouldnotbeconnectedtothe input
signal source.
FIGURE 1

IntermodulationDistortion
tntermodufationvs.power output ofa typical 6233, both channelsdriven
simultaneously into 4 Q loads. SMPTE standardtestconditionswere used: 60-Hz
and 7 kHztesttonesina 4:1ratio.
Frequer , ..
Outputofa typicalunitat1 W into a 4 il load.
Phase Shift
Phase shiftvs.frequencyofa typicalunittakenat1W into a 4 (1load.Notethat
phase shiftof less than±15°cannotbeperceived,asshownbythe dotted lines
representingthethresholdofperception.
Threshold ofClipping
Outputofa typical6233measuredjustbelowthelevelofclipping, both channels
drivensimultaneously into 4 (1 loads.
TotalHarmonicDistortion
Total harmonicdistortionofa typicalunit, both channelsdrivenat300W continuous
sine wave into a 4 (1 load.

inismanualsGctioncontainstheinformlationnecessary
toryou to completelymaintain the 6233DualChannel
Power AmplifierTheinformation is containedunder
headings of: MAINTENANCE ACCESS.VOLTAGE
CONVERSION AND LINEVOLTAGESELECTION,
INPUT IMPEDANCE CHANGE OPTIONS. Werecom-
mendthatyouthoroughlyread and understandthis
section of themanualbeforeattemptinganymainte-
nance procedures.
Maintenance Access
The followingproceduresare tobe used to gain access
tovariousportions ofthe 6233. Carefully follow the
numericalsequence of Table 1 and the explodedview
ofFigure 4 to gain access to particularportions of
theunit.
FIGURE 4
Table 1
MAJOR PARTSACCESS REC
OMMENDED REMO
CAL
SEQUENCE
_ _ - -•• • ,
ACLIKE VOLTAGE RECTIFIER |
i
1
5*
!
18 L
2" »
! 1 !
LI:TE VOLTAGE FILTER CAPACITORS
(C403 and 0404)
1 1
18 23 |l2^
I
AXIAL FANi
1 13
5:^22~
BIPOLAR FILTER CAPACITORS I
(C410 and 0411) !
1
13
23
61 253
!
1 I
i
AIR FILTER
21
t
\ 1
FRONTPANEL
1 i
|
18 ' 21
20 J_
26H ,
278| 288! 19;
-5 J r 1
HEAT SINK ASSEMBLY i
1
x3
i 1
i
INVERTER RECTIFIER
i !
I
C1C|
1
| 1 \
INVERTER PCBOARDi
i
I i
b
~~[
LEVEL LAMP ASSEMBLY
/|
—i
ON/PROTECT ASSEMBLY
—i
J
POWER SWITCH 118
_
POWER AMPLIFIER
(CHANNEL #1)
l
2 3
POWER AMPLIFIER
(CHANNEL §2)
—
18 17 16
—
—i-
VOLTAGE AMPLIFIER
(CHANNEL #1)
1
VOLTAGE AMPLIFIER
(CHANNEL #2)
18
RFI FILTER
(Reference Internal dwg 50733)
1 18
23
VOLTAGE SELECT SWITCH
1
i?_
k _
__l
Fig. & Index No.
JBLPart No.
Description
1
52115 TopCover
33
Channel #1 Voltage/Amplifier Assembly
2
VoltageAmplifier
3
Shield
4
Power Amplifier
5 52694 TopCover,Heat
Sink
6
Inverter P.C. Board Assembly
7
52124
SidePanel-Left
8
Full Wave Bridge Rectifier
(CR402)
9
Full Wave Bridge Rectifier
(CR401)
10
Axial Fan
11 Capacitors
(C403 & C404)
12
Capacitor Mounting Bracket
13
Voltage Select Switch
14
Heat Sink Assembly
34
Channel #2 Voltage/Amplifier Assembly
15 Power
Amplifier
16
Shield
17
VoltageAmplifier
18 52115 BottomCover
19 Power
Switch
20 52104
Filter
21
52103
Bezel
22 53788 BottomCover,Heat
Sink
23 52695
Cover, RFI Filter
24
Capacitors
(C410 & C411)
25
Capacitor Mounting Bracket
26 Knobs
27
On/Protect P.C. Board Assembly
28
Level Lamp P.C. Board Assembly
29 52132
FrontPanel
30 52116
Rear Panel
31
RFIFilter
32 52127
SidePanel-Right
Notes: 1.
Requires removal of3.75 inchboltholdinginvertertransformer/inverter
PCboard to chassis.
2.
Requires removal oftwo Phillips-head screws on bottom of chassis andtwo
screws holding bracket to chassis.
3.
Requires removal of four Phillips-head screws on bottom of chassis to remove
cover holding capacitors, (C410and C411).
Note: DONOT remove thetwo Phillips-head screwsholding the cover
to the capacitors until the cover is removed from the chassis.
4.
Requires removal of knobs and potentiometerhardware.
5.
Requires removal of four Phillips-flat headscrews on front panel.
6.
Requires removal of seven Phillips-head screwsfromouter side panels.
7.
8.
Requires removal of four Phillips-flat headscrews on bottom of inverter
shield cover.
Requires removal of Molex plugbeforeremovingassembly.
9.
Requires removal of six Phillips-headscrews on backpanel and four
Phillips-headscrews on outer sidepanels.
10.
Remove two quick disconnectterminals offthe thermalbreaker ontop
of the heat sink.

WARNING
THIS SECTIONOFTHE MANUAL
CONTAINS SERVICE INSTRUCTIONS
FOR USEBYQUALIFIED SERVICE
PERSONNEL ONLY

Voltage Conversion and Line voltage Selection
The 6233canbeoperated from eithera 100-120VAC
or200-240V ^050/60HzsourceTheiNPiJT
VQl^AGE SELECTOR onthemarpanelconvertsthe
amplifier from oneoperatingrangetotheotherUse
the following proceduretoconverttheamplifiervoltage
ranges
1. Disconnecttheamplifier from thepowersource.
2 Toconvert from 100-120VACto200-240VAC,
rotatethe INPUT VOLTAGE SELECTOR screwdriver
biui LU tiit?desiredvoltayeir iu iCauon.
3. Changethelineand/orattachrnent plug tomatch
thesupplysourcereceptacle,orusea 120V to
240 V ACadapter(notprovided].Theadapteras
wellasthepowersupplycordand/orattachment
plug usedforthe240V ACmodeintheU.S.,
Canada and Japan shallbe both ULListedandCSA
Certifiedforuse with saidpowersourcereceptacle.
For useinothercountries,adapter,linecordand/or
attachment plug selectionshallbebasedonlocal
regulationsgoverning240V **0,50/60Hzsupply
sources.
4. Changethelinefuse from a 16A,type3 ABtoa
8 A,type3 AB.
CAUTION: This unit maybedamagedifoperated
with the INPUT VOLTAGE SELECTOR settothe
incorrectpositionforlinevoltageapplied.
CAUTION: The623\ isdesignedtobeused with
a three-wireACpowersystem.Ifthethree-totwo-
wireadapterisusedtoconnectthis unit toa two-wire
AC powersystem,besuretoconnecttheground
lead oftheadaptertosafetyearth(ground).Failure
tocompletethegroundsystemmayallowthe chassis
oftheamplifiertobeelevatedabovegroundpoten-
tialandposea shockhazard.
InputImpedanceChangeOptions
InpsO sonr>ecdoosma;becone*"dYecccoup:eoor
transTcrmer- soiareca-me/.LRconnectorsJ SCO or
J222 Directcoupling»saccomplishedbytheuseof
snoringmugs JEcar> cc53620 Tnese cocas ?/e
inc!a"ed andsOopedzj thetactoryFigure5
For transOrmer-;scateainputsa 5135matcnng/
hedgingtra-stormerrrmsroep'uggec»mome9-c«n
receptacles ><A401or XA4C2 requiringremova'ofthe
topcover.
WARNING
THIS SECTION OF THE MANUAL
CONTAINS SERVICE INSTRUCTIONS
FORUSE BY QUALIFIED SERVICE
PERSONNEL ONLY
For 15kObalanced input, connectthe input per
Figure 6 andreplacetheshorting plug with a JBL
5195transformer.
FIGURE 5
For a 600O balanced input, wiretheXLRconnector
perFigure1 andreplacetheshorting plug with a JBL
5195transformer.
FIGURE 6
U.l.and C.S.A. LineVoltageWiringCode
Safety Earth
Country
Line
Neutral
(Ground)
U.S., Canada, Japan
Black White
Green
Europe (U.S., Canada & Japan
Optional, but Acceptable)
Brown Blue
Green/Yellow
FIGURE 7
The input nfthem°2Tc^nL<^icwi^d0 > provide
14 dBofadditional gain m morue5 0)5ttansformei
The REDwiresOd^edtop.n#2c!\'v*4Qim WA402
15 rttliUVt-JaML! mvj-doK J IVJpi I ! ~t 0 0 si C>Ji IIIGUI
dt;cnFigure8 nomcu.te<imnation^ rnqmrnd
F t
OOr"E Ftm s co^Ogu-aco^me mput s^gna: rnus1"
note/.eeed-4oB,orsaturat.ocofmemaicnmg.-
ondging transformervm:result

WARNING
THIS SECTION OFTHEMANUAL
CONTAINS SERVICE INSTRUCTIONS
FOR USEBY QUALIFIED SERVICE
PERSONNEL ONLY.
Recommended TestEquipment" —
instrumentType
Required Characteristic
Recommended instrument
Test Oscillator
Frequency Range:20Hz-20kHz
Distortion: Less man u.Ouib
Output:1 V RMSMm.
Hewlett-Packard
HP339
DistortionAnalyzer Measurableto
0.0018
Oscilloscope
BandwidthDCto50MHz Tektronix
Model 465
Multimeter
Accuracy: 0.1%reading+1digit
DC Range:±199.9mVto±1199V
AC Range:199.9mVto1199V
InputImpedance:10mO
Fluke Model 8000A
OutputLoad Resistors
Total500W pereachchannelat4 O
(Non-inductivetype) Dale
NH-250 250W
8O V,1%,4 required
Resistor Decade 1O-100kO
VariableAutotransformer Mustbecapableofsupplying1.5kVAovera rangeof90-136V
GenRad Model W20MT3A
Wattmeter
Range of180W mmand1500W max.
Current-measuring Probe Termination:
Passive
Sensitivity: 2 mA/mV
Accuracy: 3%
Tektronix Model P6021
1XProbe
10XProbe
Frequency: 50MHz Tektronix
Model P6062A
Block Diagram

WARNING: DisconnecttheACpowercordfrom
theamplifierpriortoremoving covers. Exposed
terminalswithintheamplifier[including several
pointsontheprintedcircuitboards)cansupply
sufficientenergyto cause injuryordeath.
Power Supply
Ifanycomponentintheinvertersupplyisreplaced,
thefollowingverificationstepsmustbefollowed:
•1.Diodes CR1, CR2,CR3andCR4mustbe
checked for FORWARD and REVERSE resistance.
Readings between2.1and2.3Oarenormal.
NOTE: Theforwardand
re^er?^
readingswill
beidenticalasmostmeterswillnotdevelop
sufficientvoltage across the2 Q resistorsto turn
onthediodejunction.
•2.Aninfiniteresistancemeasurementshouldexist
betweenthe case oftransistorsQ1,02,Q3and
Q4 oftheinvertersupply,heatsinkandground.
Also, aninfiniteresistanceshouldexistbetween
theheatsinkandthecollectorsoftransistors
01. 02,03andQ4.
•3.Theinvertersupplyshouldstarttooperatewith
approximately30V ACappliedwiththe INPUT
VOLTAGE selectswitchsetat100-120V position.
NOTE: Thestartvoltagewillbedoubleinthe
2U0--240 V mode.
•4.Witha 120V ACinputanda currentprobeat-
tached toeachofthefollowingcolor-codedwires:
ORG/BLK#11
YEL/BLK #12
BRN/BLK #13
RED/BLK #14
The followingwaveforms MUST matchthescopetrace
shown inFigure9.
Collectorcurrent, IDLE
POWER 2 A/divverticle.
10 fis/divhorizontal.
Bump MUSTdisappearat FULL
POWER. Ifnot,replaceallfour
invertertransistors.
Collectorcurrent. FULL
POWER, 2 A/divverticle,
10 /us/div horizontal.
RGURE9
WARNING
THIS SECTION OFTHEMANUAL
CQNTA'NS SERV!0E INSTRUCTIONS
FOR USEBYQUALIFIED SERVICE
PERSONNEL ONLY.
NOTES;
A. Ifanyofthetracesdonotmatch, turn the
unitoffandreplaceALL FOUR INVERTER
TRANSISTORS.These transistorsmustbe
orderedasa setoffour.
Color codedidentificationofthese
transistors mustmatchin sets offour.
Replacement sets dcnetneedtohavethe
same colorcodeindentificationasthe
original.
B. Wiresattachedtotheinverterboardare
colorcodedasfollows:
Base colorIndicatestransistor
Stripe Indicatesfunctionterminal
Black Collector
WhiteEmitter
Nostripe Base resistor
Blue Base
•5.Normalidlepowerconsumptionis160-180W.
Maximumidlepowerconsumptionis200W.
•6.Beforeplacingtheshieldovertheinvertersupply,
make surethewire harness doesnot pass over
theresistorandcapacitorbank.
•7.Withtheamplifierrunningat full rated output at
1 kHz.confirmthatthecurrentwaveformsof
transistors Q1,Q2,Q3andQ4arebalanced
within±10%,andhavenoleadingorlagging
short spikes.
AmplifierAssembly
WARNING:DisconnecttheACpowercordfrom
theamplifierpriortoremoving covers. Exposed
terminalswithintheamplifier[including several
pointsontheprintedcircuitboards]cansupply
sufficientenergyto cause injuryordeath.
Ifany output deviceisreplaced,thefollowingverifica-
tion stepsmustbefollowed:
•1. Bias voltage across resistorsR9.R11.R13.R18,
R20 andR22mustmeasure12mV± 5 mV.
NOTE: Unitmustbewarmbeforemakingbias
measurements. A minimumof5 minutesisrequired
atidlecurrent.Measureonlythatvoltageamp/
powerampassemblythatisinthewindtunnel,
makingsurethatthechannelthatisnotbeing
measured isnotshortingagainsttheunit.
•2.Verifythatallwire/screwconnectionsare tight.
•3.Beforereplacingtheshield,checktheclearance
betweenthetopofresistorsR42.R45,R48and
R50 andthe chassis. Itshouldbe3.175mm
[0.125 inches).