Read JBL ESC 550 Source (serv.man2) Technical Bulletin online
Service Bulletin
Service bulletin JBL9704 - July 1997
Warranty labor rate: MINOR repair
To:
All JBL Service Centers
Models: ESC550 - The Source
Subject: Surround level changes during CD search mode
In the event you receive a ESC550 system (including the Source) with the complaint that the
surround level (rear channel volume) changes during the CD search mode:
surround level (rear channel volume) changes during the CD search mode:
Procedure:
1) Lay unit face down. Remove the 5 Phillips screws holding the upper & lower case together; separate
cases.
2) Locate C707 (.022uf 50v cap.) on the main PCB in the bottom case.; replace with 470uf 10v electrolytic
capacitor (JBL# 3479347121). Observe polarity; negative terminal should be closest to connector
CN702. It should be possible to cut the original cap off the board and re-solder the replacement without
removal of the main PCB. See drawing.
CN702. It should be possible to cut the original cap off the board and re-solder the replacement without
removal of the main PCB. See drawing.
3) Locate solder pads for connector CN702 on the Control PCB in the upper case, near the headphone
jack. Adjacent to the slot cut in the PCB for the 11 conductor cable, solder a .01uf ceramic cap
(JBL# 3519103935) to pins 8 and 11 on the solder pads. See drawing.
4) Re-assemble unit; test as follows:
4) Re-assemble unit; test as follows:
a) Plug in unit, assure all cable and speaker connections are intact. Insert CD of choice.
b) Turn power ON to the Source and the Bass550 subwoofer; (display on the Source should now be
b) Turn power ON to the Source and the Bass550 subwoofer; (display on the Source should now be
active).
c) Toggle “surround mode” button on front panel or with remote control until “NORMAL” appears.
e) Adjust volume (on the Source) so display reads “VOLUME 30”.
d) Press PLAY button on the Source or the remote control.
e) Press the SEARCH/TUNE button on the Source or the remote control to search up or down
e) Adjust volume (on the Source) so display reads “VOLUME 30”.
d) Press PLAY button on the Source or the remote control.
e) Press the SEARCH/TUNE button on the Source or the remote control to search up or down
selected track.
Model
Serial number
Action
Correction
ESC550 (Source)
Under 11500
Jumps randomly to surround
(rear) channel level during CD
search mode
Replace C707 with 470uf 10v cap.
Add .01uf cap. to pins 8 & 11 of
CN702
ESC550 (Source)
11500 and higher
Modified by factory
NONE REQUIRED
JBL Incorporated 80 Crossways Park West, Woodbury, New York 11797 (516) 496-3400
JBL Incorporated 80 Crossways Park West, Woodbury, New York 11797 (516) 496-3400
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