Service Bulletin Jbl9903 - April 1999 - JBL PSW-D115 Service Manual

Amplifier/Subwoofer
To:All JBL Service Centers
Models: PSW-D115
Subject: Check Solder Joints in Event of Failure
Some performance related complaints in the PSW-D115 powered Subwoofers may be caused by cold solder
connections between the 28 pins of the Power Amp Module and the main circuit board. When troubleshooting,
failure to check these joints can result in erroneous conclusions or wasted time.
In the event you receive a PSW-D115 Subwoofer with the complaints "Dead, or No Output, or
Motorboating (Oscillation)", perform the steps listed below first before any further
troubleshooting takes place:
1)
Unplug all cables, lay the subwoofer on a padded surface.
2)
Remove all Philips screws around the outer perimeter of the amplifier faceplate.
3)
Remove amplifier assembly; you should be able to remove the amplifier far enough out of the cabinet to
service it without removing the woofer wires.
4)
Locate the Power Amp Module; it is the large gray component with a metal case. On the solder side of the
circuit board are the 28 soldered connections to the Module.
5)
Regardless of whether you can visibly see breaks in any of the connections or not, carefully re-solder all 28
pin connections, adding 60/40 rosin core solder. Take care not "bridge" any connections on the board with
solder.
6)
Inspect the solder joints to the main filter capacitors C1 and C2 on the main PCB and re-solder if needed.
7)
Replace the amplifier assembly back into the cabinet; replace the screws.
8)
Test the unit by applying a signal from a music source, adjust the volume to a moderate level and confirm
the original problem has been corrected.

SERVICE BULLETIN JBL9903 - APRIL 1999

This is considered a Minor repair
PSW-D115
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