JBL ES 250P (serv.man2) Service Manual ▷ View online
Yes/No
Hi/Lo Line
Nom.
Unit
Notes
Turn-off Transient
0.5
V-peak
0.8V
@ Speaker Output
AC Line cycled from ON to OFF
Efficiency
Efficiency
65
%
60
Test conducted at rated power
250W
Nominal Line voltage
Efficiency at 1/8 of rated power
48
%
45
Test conducted at 31.25 WRMS Nominal Line voltage-Rated impedance 4 Ohms
Off state input power
10
Watts
12
Nominal Line voltage RED LED
Stand-by Input Power
18
Watts
18
@ nom. line voltage
Maximum allowable input power under nominal
Input voltage and frequency, HOT or COLD
operation. LED GREEN no signal applied
Power Cons. @ rated power
406
Watts
416
@ nom. line voltage
250 Watts @ 4 Ohms nominal line voltage
Protections
Short Circuit Protection
YES
functional Direct short at output
Amplifier should resume operation after short
circuit condition removal
Thermal Protection
YES
functional
@1/8 max unclipped Power at
1.06 times the input voltage
Temperature rise in accessible metal parts
should not exceed 35K rise for domestic version
requirements sheet).
DC Offset Protection
YES
-
DC present at Speaker Out leads
Design must insure no Offset at the speaker
output under any operating condition including
abnormal operation
Line Fuse Rating
USA-Domestic
3.15
Amps
3.15
Type-T or Slo Blo-250 V
EU
2
Amps
2
Type-T or Slo Blo-250 V, Low
Breaking capacity
Other Parameters/Notes:
1. Limiter circuit response must be clean sounding with no apparent pops, noises, or pumping.
1. Limiter circuit response must be clean sounding with no apparent pops, noises, or pumping.
2. Volume control should be at the input buffer stage in order to lessen the possibility of clipping the input section with highly dynamic audio material.
3. ALL SPECS SHOULD BE MEASURED AT NOMINAL LINE VOLTAGE.
ES250P
JBL ES 250P
Service Manual
Page 13 of 30
ES250P Test Set Up and Procedure
Equipment needed:
•
Function/signal generator/sweep generator
•
Integrated Amplifier
•
Multimeter
•
Speaker cables
General Unit Function (UUT = Unit Under Test)
1) From the signal generator, connect line level (RCA) cables to the Subwoofer Line Level Input jacks L/R on
the UUT. Use a Y-cable from a mono source if necessary to connect to both inputs.
2) Turn the CROSSOVER control to maximum (150).
3) Turn the LEVEL control on the UUT to completely counterclockwise (MIN).
4) LFE/NORMAL switch should be in NORMAL position.
5) PHASE switch position does not matter.
6) Turn on generator; adjust to 50mV, 50 Hz.
7) Plug in UUT; turn the power switch ON. LED should switch from Red to Green.
8) Turn LEVEL control full clockwise (MAX); immediate and vigorous bass response should be heard and felt
from port tube opening on the bottom.
9) Turn off generator, turn LEVEL control full counterclockwise (MIN), and disconnect RCA cable.
Sweep Function
1) Follow steps 1-8 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 woofer and test.
Driver Function
1) Remove woofer from cabinet; detach + and - wire clips.
2) Check DC resistance of woofer; it should be 3.6 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.
ES250P
JBL ES 250P
Service Manual
Page 14 of 30
ES250P Troubleshooting Flow Chart
yes
no
no
yes
yes
no
yes
no
yes
no
yes
no
yes
no
yes
no
no
yes
yes
no
Start
Dc voltage check
±Vcc,±15V
O
Check transformer
C
168,
C
169
,D
123
,
D
124,
C
170
Power on check
LED red &green
O
Check vol module
& connector
cable& ±15V.etc
Check THD output
power, noise
O
Check pre board
& power board ,
±Vcc,±15V etc
Test frequency
Response
O
Check U
102
,uR
133
,
C
121,
R
135
,C
122
.etc
Test input sensitivity
O
Check U
101
,R
117,
R
112,
R
114
etc
Test protection
O
Check U
107
.R
237
±15Vcc etc
Test limiter circuit
O
Check U
106
.Q
107
etc
Auto off Function
Hi pot test
O
Check U
103
.Q
101.
Q
102
.C
131.
R
142
;Ac
cord, Transformer.
O
Listening test
O
The Amp ass’y ok
END
Test phase sw,low
pass sw rabos vr
Check sw103,102,
R158,163,177 etc
ES250P
JBL ES 250P
Service Manual
Page 15 of 30
ES250P
JBL ES 250P
Service Manual
Page 16 of 30
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