Service Bulletin Jbl 2001-07 - JBL PowerBass PB12 Service Manual

PB12
Service Bulletin JBL2001-07 Rev1 - February 2002
To: All JBL Service Centers
Model: PB12 (Revision 1 only)*
Subject: Possible Missing Diode D4
In the event you receive a PB12 subwoofer for any servicing reason, check for the presence of
diode D4 on the Main PCB close to the Power Amp Module (see illustration). If D4 is missing or
has been "cut out" of the circuit, it should be replaced; add JBL part# 50115. Observe polarity.
Note: The presence or absence of D4, in itself, does not contribute to, or solve, an amplifer failure.
Purpose of D4 is to reduce the possibility of an occasional Turn-OFF pop noise.
Reference for general location only; all parts or designators may not conform exactly to this drawing.
* Revision 1 of the PB12:
Amplifier faceplate says "Made in Canada"; Amplifier serial number starts with "AM"
Black (or silver) potted, non-serviceable S64AMI output module.
Service Bulletin
This is considered a Minor repair
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