J-654 hamProAudio
TM
Microphone Equalizer/Conditioner
Instruction & Technical Manual
-23-
IN CASE OF DIFFICULTY
[ ] Won’t Power up:
Check the polarity and connection to your power supply.
[ ] No microphone audio:
Check the Mic Audio Jumper block and the Mic
Ground Jumper block for proper placement of the jumper
on the proper header
position. Also if using an electret microphone element ensure the proper
phantom voltage is programmed using the proper jumper.
[ ] No receiver audio:
Check the cabling from your radio to the MFJ-654.
Ensure the Test/Operate switch on the rear of the unit is in the Operate position.
[ ] Station PTT will not function:
Check the PTT jumper block. Ensure that
you have a ground between the radio and the MFJ-654 as the Mic Ground is
isolated from the Chassis Ground.
[ ] Noisy audio, Hum:
Magnetically induced hum can be caused to any modern
piece of audio equipment by proximity to unshielded power transformers or
equipment that radiated strong AC fields. Another source of hum can be caused
by a ground loop. This is when equipment is connected together but do not have
their grounds well connected. The use of “Daisy Chain” grounding techniques
can contribute to this problem. The use of a single point ground is always
recommended in Amateur Radio installations. RF floating in the shack can also
contribute to distortion. To determine if you have this problem simply transmit
into a Dummy Load. If the distortion goes away then you have RF in the shack.
TECHNICAL ASSISTANCE
If you have any problem with this unit first check the appropriate section of this
manual. If the manual does not reference your problem or reading the manual
does not solve your problem, you may call
MFJ Technical Service
at
662-323-
0549
or the
MFJ Factory
at
662-323-5869
. You will be best helped if you have
your unit, manual and all information on your station handy so you can answer
any questions the technicians may ask.
You can also send questions by mail to MFJ Enterprises, Inc., 300 Industrial Park
Road, Starkville, MS 39759; by Facsimile (FAX) to 662-323-6551; or by email to
[email protected]. Send a complete description of your problem, an
explanation of exactly how you are using your unit, and a complete description of
your station.
Schematic (Conditioner)
