AVR 500 (serv.man10) - Harman Kardon Audio Technical Bulletin (repair manual). Page 2

harman/kardon Incorporated  250 Crossways Park Drive, Woodbury  New York 11797  (516) 496-3400

2

Models: AVR300, AVR500  Subject: Random Noise, Erratic Output in DTS Mode

9)  Ground Reinforcement:

Using an insulated 16AWG wire, Connect Negative sides of the following capacitors on the bottom side of the
PCB as shown below. Negative side of each cap will have a white mark on the component side of the PCB.

A.  Negative polarity of C746 Elec Cap (1uF/50V) in the proximity of ROM IC709
B.  Negative polarity of C749 Elec Cap (1uF/50V) in the proximity of IC708 DSP IC
C.  Negative polarity of C744 Elec Cap (1uF/50V) in the proximity of IC710 74VHC574

10)  Replace:

Change both R756 & R755 from 600

Ω

 to 33

Ω

 1/10W SMD resistors (h/k part#

 292-33.2)

. See

location below.

11) Replace DSP PC Board back into its (3) receptacle plugs atop the MAIN PCB.
12) Replace all screws, braces, and any cable ties that were cut during disassembly. Before tightening the

screws, make sure all PCB’s and their RCA jacks are firmly seated in their respective holes in the rear
backplate. If using a power tool, use care and minimum effort to avoid damaging the various plastic
receptacles.

13) Plug both the 22 conductor ribbon cable and the 5 conductor molex cable back into their receptacles.
14) Replace the top cover and optical plugs.
15) Test unit by powering up the receiver and playing a source with DTS encoded material; confirm the

complaint of Random Noise or  Erratic Output is no longer occurring.