NAD M56, Service Manual

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TRAINING MASTER FOR BLU-RAY (BD)
Does the noise only
happen when a disc
is playing?
NO
YES
BDs make a slight hum when playing discs.
A clicking noise or a noise interfering with audio may indicate a problem.
Try multiple discs. Multiple discs with the same issue means the
BD may need service or be professionally cleaned.
Check BD service for service instructions.
Does the noise happen
when the BD is turned on?
NO
Check to see if a disc is inserted into the BD and eject the disc.
A humming or clicking noise when the disc is not inserted
may be a cooling fan. Check OM to see if cooling fan is present.
If not, unit will need service. See BD service for service instructions.
4-3. Humming/Clicking Noise
The unit is making a humming noise or a clicking noise.
Has the customer tried
multiple tapes and discs?
NO
YES
YES
If the issue only shows up on one disc, then the problem is
with that disc. Have the customer try multiple tapes or discs.
If the issue happens on multiple discs and tapes,
then ask the customer to try a lens or a head cleaner.
Has the customer
connected to another TV?
NO
Ask the customer to connect the product to another TV.
If the issue persists, try another set of cables. If the issue still persists,
then the issue is with the unit. The unit will need service.
Arrange service following proper procedure.
How are the cables routed?
NO
Make sure cables are routed properly.
Make sure audio and video cables are routed to the same source
(if possible). Routed audio and video to separate products
can cause a bit of a delay between the devices as not all devices
will process audio and video signals at the same speed.
4-4. Audio/Video Out of Synch
The audio and video do not match up. People look to be talking, but their voices are delayed by a few seconds.
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