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harman/kardon Service Bulletin
Service bulletin # 9604 rev1 - October 1998 This is considered a Minor Repair
To: All harman/kardon Service Centers
Models: FL8300
Subject: Digital Output Level
The Digital Interface Standard recommends D/A converters have a minimum Input sensitivity of 200 mV.
In early FL8300 production units, the Digital Output level was 240 mV ±10% peak to peak. Based on our research,
we found that some D/A converters require more than 240 mV for intermittent free operation.
In the event you receive a FL8300 from a consumer with the a complaint “Intermittent Sound from External
D/A converter”, check the serial number in the table below.
If the FL8300 has a serial number higher than indicated in the table below, connect a properly working D/A converter
to the Digital Output and verify interruption free operation. Also confirm the Digital Output level of the FL8300 is 500
mV ±10% Peak to Peak. If the FL8300 passes these two tests, advise the customer to have their external D/A
converter and connecting cables checked.
If the FL8300 has a serial number lower than indicated in the table below, perform the following
modification:
1) With the unit plugged in and turned on, push the “open/close” button to extend the drawer fully; then turn the unit
off and unplug it.
2) Open the top cover (6 screws).
3) Remove output board PCB3 from the rear panel (4 screws). This board can be pulled back and modified without
completely removing it from the chassis.
4) Locate resistor R901, it may be a 680 ohm resistor or a jumper wire; replace in either case with a 0.47
uf capacitor h/k part# 5354-474593.
5) Locate R903 and change from 680W to a 4.7kW resistor - h/k part # 3029472970. Re-attach output PCB3 to the
unit.
6) Connect a 75 Ohms cable to the digital output jack. Terminate this cable with a 75 Ohm load; connect an
oscilloscope to the 75 Ohm termination resistor. While playing a CD, confirm the output of the signal is now 500
mV ±10% peak to peak.
7) Reassemble the FL8300 and test all functions.
Model Serial number
120V
Serial number
230V
Status Action
FL8300 IN0019-01001
to
IN0019-19393
IN0020-01001
to
IN0020-04500
May have low digital
output for some
applications
Replace R901 with 0.47 uf mylar
capacitor h/k part# 5354-474593
Replace R903 with 4.7k ohm resistor
h/k part# 3029472970
FL8300 IN0019-19394 IN0020-04501 Factory Installed * NONE REQUIRED
* Factory modification of the FL8300 starting with the serial numbers indicated in the above table consisted of:
R236: 1k Ohm
R901: Jumper or 680 Ohm
R903: Changed from 680 Ohm to 4.7k Ohm.
Digital output level into 75 Ohms: 500 mV ±10% peak to peak.
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