5-6
TROUBLESHOOTING ORBAN MODEL 8685
System will not pass line-up tones at 100% modulation
• This is normal. Sine waves have a very low peak-to-average ratio by comparison
to program material. The processing thus automatically reduces their peak level
to bring their average level closer to program material, promoting a more consis-
tent and well-balanced sound quality.
• The 8685 can generate test tones itself. The 8685 can also be put into Bypass
mode (locally or by remote control) to enable it to pass externally generated
tones at any desired level. (See Test Modes on page 3-64.)
System will not pass Emergency Alert System (“EAS” USA Standard) tones at the
legally required modulation level
• See System Will Not Pass Line-Up Tones at 100% Modulation (directly above) for
an explanation. These tones should be injected into the transmitter after the
8685, or the 8685 should be temporarily switched to a
PASS-THROUGH preset to
pass the tones.
System Receiving 8685’s digital output will not lock
• Be sure that the sample rate at the 8685’s output is set to match the sample rate
that the driven system expects. (Use the S
URROUND OUTPUT RATE or 2.0 OUTPUT
RATE control as appropriate.)
• Be sure that the 8685’s output mode (AES3 or SPDIF) in the active Setup is set to
match the standard expected by the driven system.
• In synchronous systems like TV facilities, be sure that you have set up the 8685’s
digital outputs to lock to your desired reference, which can be an AES3id signal
applied 8685 digital input 1/2 or a word clock reference applied to the 8685’s
Sync input. If the optional HD-SDI module is installed, the 8685 will also sync to a
signal applied to the video reference input or the HD-SDI input. See step (9.B) on
page 2-27 for 2.0 outputs and step (12.B) on page 2-33 for surround outputs.
System will not lock to video sync at 88.2 or 96 kHz
• Synchronization of 88.2 or 96 kHz audio sample rates from the video reference
input only works for integer fame rates, not pull-down frame rates.
AES Channel Status Bits will not set the 8685’s 2.0 processing to Stereo or Dual-
Mono mode.
• Be sure that the equipment driving the 8685 is set in AES3 or AES/EBU mode.
(SPDIF will not work.) Similarly, you must set the 8685’s digital output mode (via
the S
URROUND OUTPUT FORMAT or 2.O OUTPUT FORMAT control) to AES in order to
send AES channel status bits to downstream equipment. (See step 13 on page 2-
18.)
Equipment receiving the 8685’s 2.0 Processing output changes operation mode un-
expectedly.
• Some equipment will respond incorrectly to AES Channel status bits:. Try turning
these off in the 8685. (See step 13 on page 2-18.)
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