Harman Kardon AVR 300, Руководство по обслуживанию

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harman/kardon Incorporated 250 Crossways Park Drive, Woodbury New York 11797 (516) 496-3400
harman/kardon
Service Bulletin
Service bulletin # H/K2000-05 May 2000 Warranty labor rate: MAJOR repair
To: All harman/kardon Service Centers
Models: AVR300, AVR500
Subject: Volume Level Changes
On early versions of the AVR300 or AVR500 the volume level may change by itself, or when the volume knob
is tapped. This may happen on an occasional random basis and depends on where the volume control knob is
positioned after a volume adjustment. During a running production change, new volume encoders were
installed.
In the event you receive an AVR300 or AVR500 with the complaint “The volume on my receiver
changes by itself”, perform the following procedure:
REPLACE VR901 VOLUME ENCODER
1) Remove the top cover, (14) Black Phillips screws.
2) Remove the (11) Black Phillips screws holding the plastic front panel to the chassis.
3) Remove the single Phillips screw on both right & left side of the chassis with a dual black ground wire.
4) Remove the volume, bass, treble and balance knobs by pulling them straight off.
5) Remove the single nut holding the volume encoder to the front panel.
6) Pull the loaded front panel off the chassis; cut any plastic cable ties necessary to fully disengage it
7) Lift and set the receiver on its right side for the remainder of the procedure.
8) Remove molex connector CN983 at the power switch; see Figure 1.
9) Pull the front panel as far away as the remaining connecting wires will allow.
10) Unsolder the connections at the rear of the front PCB to the volume encoder.
11) Using a “stubby” Phillips screwdriver, remove the (19) Black Phillips screws holding the front PCB to the
front panel; two plated screws at the rear of the headphone jack also must be removed.
12) Pull the front PCB away from the front panel.
13) Remove and replace the volume encoder with h/k part# J32612050102; resolder the new encoder in place.
14) Replace the front PCB and reassemble the receiver in reverse order, following the instructions above.
Replace all cable ties that were cut, and reattach any connectors that were unplugged. Make sure the two
ground wires on both sides of the receiver are reattached.
15) Power up receiver, and test volume control to assure it no longer changes settings by itself, or when the
volume knob is tapped.