Tuner Section - Yamaha CR-840 Owner's Manual

Before assuming that your CR-840 is faulty, check this double-sided trouble-shooting list. It details many steps
you can take yourself without having to call a service representative. Keep it near your CR-840 for ready reference.
TUNER SECTION
Fault
Cause
Cure
A persistent hum occurs when an AM station is tuned.
This hum can affect whole areas where broadcast conditions
are unfavorable.
Sometimes changing the position of the CR-840 will give an
improvement.
Intermittent crackling or continuous background
'roaring' on AM.
Atmospheric electricity or electrical storms, possibly fluores¬
cent lighting or other electrical equipment.
Difficult to eliminate, an external antenna and good ground
connection will give considerable improvement.
High pitched whistles, etc., particularly at night on
AM.
Signals from adjacent stations are interfering with reception.
The CR-840 is being operated too near a TV set.
Nothing can be done to cut out this interference completely
but try the HIGH filter.
Increase the separation between the TV and the CR-840.
The desired station cannot be received at the correct
frequency on the dial.
The station strength may be low, and the MUTING circuit
may therefore prevent audition.
Switch the MUTING/OTS from ON to OFF.
A stereo station is heard monaurally.
The MODE switch is set to MONO.
Push and release to the STEREO position.
Occasional crackling interference (particularly with
remote, weak signal stations).
Electrical noise from automobiles, etc., or from other electrical
equipment.
Set up an external FM antenna, as high and as far from the road
as convenient: use coaxial cable. Fit an interference suppressor
to the offending item where possible.
Disturbing levels of 'hiss' noise when on FM stereo
stations.
FM stereo broadcasts are inherently more liable to this at
remote, low signal strength locations.
Set up an external FM antenna; if you are already using one, orient
it towards the station or replace with a more sensitive array.
Alternatively or additionally, listen with the MUTING/OTS
switch set at OFF,
Local stations suffer from unclear, distorted sound.
Signal input from the antenna for these stations is too strong.
Connect an attenuator between the FM antenna and the CR-840,
or turn the antenna away from the strongest (closest) station.
During stereo test transmissions, sounds which should
come from only one channel can be heard faintly over
the other.
This is known as crosstalk, and normally occurs to some extent.
Provided the sound level is very faint compared with the normal
level for that channel, no fault in indicated.
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