J. W. Davis & Company D-250AL User Manual - page 8
NEW TECHNOLOGY
OLD RELIABILITY
J.W. Davis & Company
• 3030 Canton Street • P.O. Box 710219 • Dallas, Texas 75371-0219
Sales 800-527-5705 • Fax 800-388-9106 • Corp 214-651-7341 • Fax 214-939-0328 • sales@jwd.com • www.jwd.com
Power Indicator on
Front Panel Does
Not Glow:
Overload Indicator
on Front Panel
Glows Steadily:
No Audio
Output:
No Automatic
Muting of Input
Signal:
No AC power present
Unit’s AC circuit breaker is
tripped
• Verify the unit is receiving AC power.
• Verify the AC circuit breaker is not tripped. If so, depress the
plunger to reset.
• Verify the unit’s internal fuse(s) has not tripped. If it has,
replace the tripped fuse with the same type and value fuse.
Input or output impedance not
matched
Signal in level too high
• Check that the proper input/output line impedance matches
the selected input/output connections used.
• Lower the signal in level.
No input signal source
Incorrect input signal connection
Incorrect output connections
600-ohm/tel-page gain control on
back panel too low
• Verify that proper signal/level is being supplied.
• Verify that the signal input connection is correctly connected.
• Check that the ouput connection has been properly made.
• Check 600-ohm/tel-page gain control setting (recessed on
back).
Internal jumper setting
Insufficient 600-ohm/tel-page gain
• Check that the internal mute jumper is not disabled. (See
page 7.)
• Check 600-ohm/tel-page gain control setting (recessed on
back).
Low, High, or
Distorted Level:
Volume setting
Signal input level is too low
Signal input level is too high
Input or output impedance not
matched
• Check the corresponding gain control on the front panel or
the 600-ohm/tel-page control (recessed on the back).
• Check that adequate input signal level is strong enough.
• Reduce input signal accordingly.
• Check that the proper input/output line impedance matches
the selected input/output connections used.
Possible low resistance or
shorted wiring across the audio in
and/or across the speaker out
SYMPTON
POSSIBLE CAUSE
POSSIBLE SOLUTIONS
The Mark of the Professional...
XI. TROUBLESHOOTING
• Verify the AC outlet has proper AC voltage available.
XII. OPTIONAL ACCESSORIES
Optional 600-ohm Isolation Transformer (IT-600)
Speaker Lightening Suppressor (SLS)
Tel-Page Line-lightning Suppressor (TLS)
Universal ADD-ON-AMP (AO-1A) used to match 4 or 8-ohm, 25V and 70V speaker line to MIC or
Auxiliary input of amplifier
Signal Matching Attenuator (AT-20A), Matches Signal from Tuner or Other high Z Device to Amplifier MIC Input
Signal Matching Attenuator (AT-20B), Matches Signal from Telephone Line or Other Low Z Device to Amplifier
MIC Input
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• Check and correct system wiring.
Signal Matching Attenuator (AT-20C), Matches Signal from 70V Speaker Line Output to AUX Input of Second
Amplifier
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