Carver pm420 用户手册
19
18
Playback Is Mixed with Hum
1.Check or replace the connecting cables.
2.Make sure that each screw terminal connection is tight.
3. Signal cables may have been routed too closely to AC cables, power transformers, motors or other EMI
2.Make sure that each screw terminal connection is tight.
3. Signal cables may have been routed too closely to AC cables, power transformers, motors or other EMI
inducing device.
4. Try connecting another source to the power amplifier inputs. If the hum stops, the problem lies with the
original source component.
Distortion
Distortion is usually caused by excessive loss in the input controls (the mixer/ equalizer / crossover can’t produce
enough output), overdriving resulting in output clipping, or current limiting caused by excessively low load
impedances.
1. Check the setting of the Input Level controls. If set too low, the preceding piece of equipment may not have
enough output), overdriving resulting in output clipping, or current limiting caused by excessively low load
impedances.
1. Check the setting of the Input Level controls. If set too low, the preceding piece of equipment may not have
sufficient output to overcome the loss.
2. Check the speaker connections and verify that all screw connections are tight and that there are no stray strands of
wire to cause short circuits.
3. Verify that the total load impedance presented to the amplifier is within the limits described in this manual for the
mode of operation selected.
Care and Service
Assistance
C a re: Wipe off the pm125/ p m 4 2 0 ’s front panel and chassis from time to time with a soft, dry cloth. If you have
something stubborn to remove, use a mild dish soap or detergent sparingly applied to a soft cloth. Don’t use alcohol,
ammonia, or other strong solvents.
Service Assistance: We suggest that you read the Limited Warranty completely to fully understand your warranty/
service coverage. Please promptly complete and return the Warranty Registration Card. Also be sure to save the sales
receipt in a safe place. It will be necessary for warranty service. If your CARVER Professional product should require
service, you may contact the CARVER Professional Technical Service Department by calling (503)978-3363 or by
writing to us at the factory address shown below. We will then direct you to the nearest in our national network of
Authorized Warranty Service Centers or give you detailed instructions on how to return the product to us for prompt
action. If you should have questions or comments, please write to the factory address given below. Please include the
model and serial number of your Carver Professional product, your complete address and a daytime phone number.
something stubborn to remove, use a mild dish soap or detergent sparingly applied to a soft cloth. Don’t use alcohol,
ammonia, or other strong solvents.
Service Assistance: We suggest that you read the Limited Warranty completely to fully understand your warranty/
service coverage. Please promptly complete and return the Warranty Registration Card. Also be sure to save the sales
receipt in a safe place. It will be necessary for warranty service. If your CARVER Professional product should require
service, you may contact the CARVER Professional Technical Service Department by calling (503)978-3363 or by
writing to us at the factory address shown below. We will then direct you to the nearest in our national network of
Authorized Warranty Service Centers or give you detailed instructions on how to return the product to us for prompt
action. If you should have questions or comments, please write to the factory address given below. Please include the
model and serial number of your Carver Professional product, your complete address and a daytime phone number.
Carver Professional
Service Department
P.O. Box 83189
Portland, OR 97283
Phone (503)978-3363 • Fax (503)978-3302
Carver Professional reserves the right to improve its products at any time. Therefore, specifications are subject to change without notice.