Harman JBL EON10-G2 Operating manual

Technical Service Manual
Rev. A
7/26/2004

TABLE OF CONTENTS
PRODUCT OVERVIEW 3
SPECIFICATIONS/FREQUENCY RESPONSE GRAPHIC 4
PANEL CONTROLS, CONNECTORS AND INDICATORS 5
BLOCK DIAGRAM 7
CIRCUIT DESCRIPTIONS 8
TROUBLESHOOTING GUIDE 19
SEMICONDUCTOR DIAGRAMS 21
FINAL TEST PROCEDURE 22
PICTORIALS OF PCB ASSEMBLIES 23
JBL WARRANTY LIMITED WARRANTY 27 - 52
SYSTEM EXPLODED VIEW
FAILURE QA CODES
SCHEMATICS / MASTER PARTS LIST

Product Overview
The new EON10 G2 compact powered speaker features a 10" woofer, increased power and a
three input mini-mixer. The EON10 G2 is ideal for AV applications, smaller musical and spoken
word performances and, when combined with the new EONSUB G2 powered subwoofer,
provides a full range sound system for small and medium sized events.
The first generation EON10 was very popular, not only with musicians, but with hotels,
meeting planners, AV companies and just about any application where portable compact sound
reinforcement was needed. Its successor, EON10 G2 offers more power, more flexibility and a
refined appearance that will make it even more appropriate for its many types of users.
The EON10 G2 has more power than the first generation EON10, with 125 watts for low
frequencies and 50 watts for the highs. The 10" Differential Drive low frequency driver uses a
neodymium magnet for light weight and reduced distortion. The one-inch JBL 2412
compression driver for the high frequencies includes a titanium diaphragm and ferro-fluid
cooling.
The EON10 G2 shares the same appearance improvements with its larger companion EON15 G2,
including new black exterior material and a mini-mixer with three inputs. An additional XLR output
allows EON Speakers to be daisy-chained together. As with other EON G2 speakers, the EON10
G2 is kept cool, not by heatsinks or fans, but by JBL's Thermomaster Total Thermal Management
System.
With its versatile cabinet design, the EON10 G2 can be used in several different ways. As a front of
house speaker, the EON10 G2 can sit on a flat horizontal surface or be raised in the air using
standard tripod speaker stands.
The cabinet has also been designed to let the EON10 G2 be snugly placed atop the EONSUB G2
for added volume and extended bandwidth. In addition, the angled back of the speaker allows
its use as a vocal or instrument monitor on stage.

Specifications
Frequency Response
Notes:
JBL Professional is continually engaged in research activities to enable further product improvement. New materials, production methods and design
refinements are instituted into the existing product without notification and, therefore, the information contained within this manual is subject to
change without notice. Rest assured that your JBL Professional equipment will always equal or exceed the published design specifications unless
otherwise stated.

Connectors

Indicators

Block Diagram

AC Input PCB
The line voltage of 117 Vac is connected at input jack P1 on the ac input PCB. Shunting
capacitor C1 reduces the probability of electronic damage that could occur should any
abnormalities exist on the input voltage. Capacitors C2 and C3 work in conjunction with
C1 to help stabilize this input voltage and reduce the instantaneous line voltage spikes that
could cause noise especially in the high frequency range. Pin 2, the neutral, is connected to
ground. Both lines of input voltage are directly connected to the 2-pole 2-position power
switch.
The operational idle current will be below the rated 2.5 amp fuses to protect the user from
fire. If the amplifier is consistently overdriven or an abnormality does exist with the
equipment, the fuses will open and current will cease to flow. After the fuses, the voltage
travels to the manually operated voltage selection switch. It is important to power down the
equipment when this switch is used to avoid possible driver damage. The switch,
essentially, determines which transformer primary is utilized. We will assume that the input
voltage is 115 Vac for this circuit description. The toroidal transformer output would then
deliver 44Vac to the power supply connector P2 on the main amplifier PCB.

Power Supply
This is the power supply circuit of the EON 10-G2. Operational voltages, necessary of the
main amplifier and processing circuits, are created on this PCB. The schematic, shown
above, contains three individual circuits: the signal shutdown, the main rectification and low
voltage power supply circuits.
Note: Voltages documented minimally differed from published results and are
attributable to component tolerance variations.
Voltage rectification by BR1 modifies the 44Vac delivered by the toroidal power
transformer at P2 into the positive and negative 29 volts. This voltage feeds the main
amplifiers and the positive and negative 15 volt power supplies used for signal processing.
C63 and C62 filter this rectified voltage, respectively.
In the second circuit, Zener diodes D5 and D6 clamp the positive and negative 29 Vdc so
that voltage regulators Q3 and Q4 output positive and negative 15 Vdc. Further filtering of
this voltage occurs by C61 and C58. An LED, D51, is serially connected with R47 to
negative 15 Vdc and functions as the pilot lamp.
The third circuit, the signal shutdown circuit, monitors several different parameters: the
presence of ac voltage, the presence of the low voltage supplies and the output transistor
temperature. Absence of any voltage or excessive temperature detected will cause
comparator U4 to trigger Q1 resulting in muting of the audio output. The time constant of
C22/R15 provides the initial speaker delay time upon power up.

Signal Input Circuitry
The above is the XLR line input circuitry for the EON 10-G2. The balanced signal from
pins 2,3 of J2 is attenuated by R40 and R39. Signal overload is contained by the signal-
limiting diodes, D4 and D1, preventing possible internal IC damage by clamping them to the
±15 Vdc supplies. This will provide a maximum of 30 volts of signal voltage swing
between the inputs of isolation IC U4A. The output signal of this IC, pin 1, is passed
through connectors RC1, and PA2 to the volume control PCB. Coupling capacitors C28,
C29, and C30 prevent dc circuit interaction but allow signal throughput to VR2 and VR3.
Once the signal is returned to the input PCB at pin 3 of RC1, it enters the switchable-
gain/sensitivity IC U4B at pin 5. When the mic/line switch, SW2, is toggled from mic to
line input, resistors, R25/R17, are serially added to R31/R6, which increases the input
impedance at J2 input thereby decreasing the signal delivered to U4A. This action corrects
the level for proper signal amplification. The opposite occurs when SW2 is toggled in the
reverse direction. Output of U4B on pin 7 enters pin 6 of summing IC U5 via R51 and C37.
The output of this IC feeds the Loop/mix circuitry IC

Tip Ring Sleeve Input Circuitry
Above is the Tip Ring Sleeve jack input circuitry. The input signals are attenuated by R33
and R46 before reaching isolation IC U5A. Multi-path feedback is used to decrease the
distortion and increase the stability of the amplifier. The output signal on pin 1 of U5
connects to pin 5 of connector RC1 where volume control, VR2, (not shown) can control the
amplitude delivered to loop/mix summing amplifier, U5B (not shown).

Loop/Mix Input Circuitry
The loop/mix circuitry, shown above, is another feature that makes the EON 10-G2 so
versatile. The user can decide which signal is output to extension male XLR jack J1. SW1
switches between the XLR input signal only or a mixture of the Tip Ring Sleeve and the
XLR input signals for increased sound reinforcement. In the “loop” or up position, the
incoming signal on XLR jack J2 is sent directly to the extension XLR jack J1. When the
switch is toggled, a mixture of the Tip Ring Sleeve and XLR line inputs are sent to the jack.
In either case, this allows the user to connect XLR cable to J1 and send audio signal to other
equipment.
Initially, the processed XLR input signal is summed with the TRS (Tip Ring Sleeve) ¼”
jack input signal at U5 via R31/R33 (not shown). Signal output from U5, located on pin 7,
passes through components C20, R35, R39, and enters the non-inverting inputs of U2A and
U2B. The bridge configuration of IC U2 allows for an increase in the voltage level while
providing a balanced output format. R3 and R5 in conjunction with C18 and C17 attenuate
electrostatic transients that could possibly be further amplified. The resultant signal
branches to SW1 where the looping option of connecting to the respective pins of XLR
output jack J1 for external amplification. Multiple feedback circuits of U1A and U1B
provide necessary isolation between the internal or main circuitry and externally connected
equipment. This configuration also prevents an increase in distortion and loading that could
be induced by external circuitry. Output of U1B is connected to pin1 of P1 for internal
amplification on the main PCB. C10 and C11 provide additional filtering of cable-induced
transients on the ±15 Vdc power supply lines.

HF Processing
The EON 10G2 utilizes bi-amplification topology to actively filter and separate the high
frequency signal from the low frequency signal. Consequently, the low frequency
processing circuits are similar. These frequency separation characteristics allow usage of
independent, dedicated components for accurate signal reproduction.
In the above circuit, the low frequency component of the input signal is effectively
attenuated by the 3-pole Butterworth filters consisting of U8B and U8A while the high
frequency signal is enhanced. Capacitive coupling is used throughout. These filters
effectively eliminate the low frequencies (from dc to about 1khz.) in a cascaded component
configuration. Signal level increases at +60db per decade beginning at the lower critical
frequency of 1.3 kHz. U7-A and B are used as signal integrators to increase the level to a
useful level for power amplification. Distortion and extraneous noise is almost nonexistent
due to the feedback loops associated with this circuitry. Thus, the output on pin 1 of IC U7
of 1.2Vpp is sent to the high frequency power amplifier.
Troubleshooting would best be accomplished by verifying signal waveforms at the
input /output of key IC’s using the oscilloscope. Further signal tracing from IC to IC noting
the individual voltage and signal levels at each pin. Any measurements that drastically differ
from the referenced documentation point to a defective stage or would at least indicate the
need for further examination.

HF Amplifier Stage
After the increase in signal level from U7 pin 1 to 1.1Vpp, the signal enters the monolithic
power amplifier IC, U3, at pin 10 via R18, C20 and R11. R12/C23 at the inputs avoid the
possibility of phase distortion in the rated 50 Watt output and effectively makes use of
common mode rejection to eliminate any induced noise within the audio range. This also
prevents any ultra-high frequency oscillation that could cause premature IC failure. C21
adds stability to the mute line and avoids any erroneous triggering from Q1. Connecting P1
pin 7 at junction R18/C20 activates the user adjustable trim potentiometer, VR1 on the input
PCB, for a more custom sound. Also, the output of U3 pin 3 is connected to P1 pin 6 and
transferred to the peak/signal detection and indicator circuitry on the input/output PCB.

LF Processing
The input signal of magnitude of .49Vpp from P1 at pin 1 from the input/output PCB enters
the first stage of the low frequency filtering circuits at R34. The two pole Butterworth filter
is used as the active filter configuration due to its flat frequency response. Unity gain to
prevent signal distortion with concise filtration characteristics begins at about the 3 kHz
cutoff frequency at a rate of -60dB/decade. U5B performs the first order filtering while
U5A continues with second order filtering to provide total low pass filtering of –
80dB/decade. The low noise NJM4580, U6A and B, provide a signal gain of two to increase
the signal level necessary to interface with the low frequency power amplifier without
adding distortion.

LF Amplifier Stage
This is the low frequency amplifier. The bridged mode configuration using two LM3886T
monolithic amplifiers, U1 and U2, enable twice the output voltage capability than if one IC
were driven alone. Therefore, it is strongly recommended this unit be connected to the
ac mains through an isolation transformer for safety purposes during the servicing of
the amplifier/ output stage. This will separate the grounds from interacting with the
test equipment, the unit under test and the technician.
A 1Vpp level output from U6 pin 1 from the low frequency processing circuits is input at
R52 and branches to each amplifier by passing through coupling capacitors C12 and C14.
Each leg carries this signal to the inverting and non-inverting inputs whereby IC’s U1 and
U2 increase the signal level to 15.6 volts.
Each audio output IC at pin 8 is connected to the detection circuit driver, Q1 (not shown
here—but located in the power supply section) for temperature, voltage and current
abnormalities. Before replacing both the output IC’s to correct a unit with a ‘no sound’
problem, check to verify that this muting line is not detecting a fault elsewhere (--for normal
operation it should be a negative low).

Peak/Signal Indicator
Signal indication is performed by the above circuitry with the possibility of three scenarios--
-normal ac signal present, no signal present and peak signal present.
Circuitwise, the high frequency and low frequency output taps are connected to D3 and D4
through R39 /R40 causing reverse charging of capacitor C55. This negative voltage is
transferred to the input PCB through interface connector P1 to window comparator U3. U3B
and U3C detect signal presence when the transferred voltage is greater than the lower
reference voltage of pin 5. Peak indication is detected when this transferred voltage is
greater than the upper reference voltage, at pin 9, which causes toggling of U3D to –15 volts
and illuminating the red portion of the LED, D52.
Voltage below the lower ref voltage causes no illumination.
Voltage above the upper ref voltage causes the red led to illuminate.
Voltage between the upper and lower ref voltages causes the green led to illuminate.
V
lower ref voltage = 0 volts
V
upper ref voltage = -3.1 volts

EON10-G2 Troubleshooting Guide
The purpose of this troubleshooting guide is to enable the experienced service
technician to quickly become familiar with the operating characteristics of the unit and to
accurately diagnose the associated symptoms of malfunctioning circuitry to their root
causes. In addition, this guide will facilitate the timely repair of the malfunctioning
equipment so that it can be returned to a satisfied owner. Since the total ‘repair time’ equals
the sum of the ‘diagnoses’ time plus the ‘circuitry repair’ time, and the ‘circuitry repair’
time is standard, the only other factor that can impact this total ‘repair time’ is the diagnoses
time. Therefore, the successful technician, must be time efficient with respect to diagnosing
and repairing malfunctioning equipment.
Isolation of the defective circuitry can be accomplished by utilizing this guide and the
circuit descriptions found on the previous pages. Generalized faults of current, voltage and
signal irregularities will constitute the bulk of the repairs necessary to the EON 10-G2.
• Visually inspect product. Many times a customer's problem with a unit can be located
just by visually inspecting the product for gross faults. This visual inspection can also
determine if the internal damage is related to equipment abuse.
• Verify the fault that the customer is experiencing. If unable to reproduce the customer's
complaint, notify the customer of your findings and obtain more information about the
complaint.
• It is suggested to always use the original JBL replacement components that are listed in
the master parts list to insure the maximum performance of JBL equipment. More
information can be obtained at the website www.JBLPRO.com.

Troubleshooting The EON 10-G2
Excessive current draw problems (shorted component)
Shorted output IC’s
U1, U2, U3
Shorted Power supply components
C62, C63, BR1, Q3, Q4, D5 and D6
XFRMR primary/secondary shorted together
No voltage/missing voltage/low voltage problems (open/shorted component)
Verify proper a.c. input voltage.
If all internal voltages are absent,
Check that fuses F3 and F4 are ok? Should be 2.5amp 2AG.
If ok, check if transformer is open? Transformer should have continuity
in primary and secondary windings. Unplug Secondary from Main PCB
and verify a.c. output voltage. At pins 1&3 on P2, it should read 44Vac.
Power supply ok? ±29Vdc at C62, C63?
±15Vdc at C61, C58?
Supply voltages at all 3 output IC’s on Pins 1,5 and Pin 4
If not ok, repair, verify and continue.
Verify ±15V at P1 pins 3& 4 on Main PCB and to P1 on input/output PCB
If absent, locate, repair and continue.
No sound (possible missing control voltage)
Verify ±15Vdc at P1 pins 3 & 4 on input/output PCB
No sound (voltages are okay),
The quickest way to isolate this problem to a specific PCB is to start with a known good
input /output PCB. Most failures are related the main amplifier or to components under
the most stress.
If problem exists on the input PCB,
Verify signal input to unit at J2 pin 2.
Verify signal output at pin 1 of P1
If no signal then verify output signal on U4 , U5, U2, U3.
Signal trace PCB accordingly using circuit descriptions.
If problem exists on main amplifier board,
Verify input signal to Main Amplifier PCB at pin 1 of P1
If no input signal at P1, replace 8-pin cable assembly
Measure dc offset on output of IC’s U1, U2, U3
If more than 2Vdc, replace defective output IC
If dc offset is ok, continue to verify input at pin 10 of remaining output
IC’s
if ok, verify status of mute pin 8 on output IC.

If mute pin 8 reads near 0 volts, change IC.
If mute pin 8 of any/all output IC’s reads close to –15 volts, recheck above
results and signal trace PCB. If the unit measures positive or close to zero the
unit is detecting a fault or there exists a problem with the fault detection
circuitry. Signal and voltage trace accordingly using circuit description.
Low output power problems
Verify proper level input at pin 10 of output IC’s
If level ok, replace IC (U1, U2—Low Frequency amplifiers
U3—High Frequency amplifier)
If not ok, signal trace back to fault using circuit descriptions, repair and
continue check out
No power On LED indicator operation
Verify -15 volt at Q3 and leg of R47
Verify -2V on opposite end of R47
If absent, change LED
No input signal indication
Verify operating voltage of ±15V on U3 of input/output PCB
Verify input signals from the low and high frequency outputs at D6 and D7
Verify C55 charging and discharging.
Verify threshold voltages by inputting external voltage to inverting pin of U3
on Input/output PCB
At 0 volts--no illumination
Below 0 volts to -3.1 volts—green illumination
At/below -3.1Volts—red illumination
If above is ok, replace IC U3 (TLO74)
No microphone LED indication
Verify 15 Volts at junction of R57/R54
Verify audio ground on cathode of DS1
Verify LED element operation. If defective replace LED.
Verify continuity of SW2 contacts