BOOM SOUND AT AUDIO MODE CHANGE

The move may have resulted in surround mode being deselected. The speaker sound check will not detect this.

go through the input modes its one of them leave it each mode on for 30 seconds what output do you have for audio on the blueray. It can also be setting for audio from blueray was turned off swich to fiberoptec

you need an active speaker. plus you need to connect it to the right output on the back of the receiver.

Not a good sign. There should be a click a few seconds after you turn on the unit. That says the output section is OK. If there is no click, you need repair. Perhaps only some fuses inside, but it could be worse.

Also make sure that the speaker switch is in the right position, like A, not A+B. Also the headphone jack can silence the speaker.
Make sure that ALL switches are in the right position.

I think you need to look at the sound settings. In particular the type of sound. HD channels often carry AAC sound, suitable for Dolby 5.1 and Standard Channels don't. So the sound system will switch modes when you change channels. However the receiver is not switching back to picking up PCM signals, the type used on SD channels.

Some surround modes don't use the center channel. This is where most vocal tracks go to.

Hello
Panasonic TV's after 1996 can be set to "Serviceman Mode" with the
following remote control sequence:

-select the SET-UP icon and select CABLE mode.
-select the TIMER icon and set the SLEEP timer for 30 minutes.
-press the ACTION button twice to get out of the menus.
-change to channel 124.
-adjust the volume to minimum (0).
-Hit the VOL down button on the TV itself (not on
the remote) and a red "CHK" should appear in the upper corner.
-press the ACTION and VOLUME DOWN buttons (again, on the
TV, not the remote) you will toggle between AGING and SERVICEMAN modes.

Select Serviceman mode. The POWER button on the remote control will
select one of the five Serviceman Adjustment modes.

The modes are:

B - Serviceman VCJ SUB Adjustments. These include sub-tint,
sub-color, sub-brightness, sub-contrast, colorkiller/ABL/gamma,
audio and video adjustment, and vertical size.

C - Serviceman VCJ Cut-off adjustments. These include Red, Green
and Blue cut-off, red and blue drive, automatic fine tuning
(AFT), RF AGC (RF gain control), horizontal center, beam limit,
etc.

S - Serviceman Options Adjustments. These involce the PIP and
clock.

M - Serviceman MTS (Stereo/SAP) adjustments.

CHK - the mode you first entered. Normal picture and sound, lets
you check things over and still have a hotkey into the
service menu.

There is one more adjustment that isn't in the five modes, it's
global. When in either the yellow or red CHK mode, you can press
RECALL on the remote control to enter the purity field check mode.
This lets you select a pure white, red, green, or blue screen. A
good thing to walk away from if you just want to temporarily freak
out the floor manager, but it will be fixed as soon as the TV is
turned off. Oh well.

To get out of Serviceman mode, press ACTION and POWER on the
receiver simultaneously for at least 2 seconds. The TV will momentarily
shut off and then comes back on.


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PE77U / PX75U / PX77U / PZ700U / PZ750U
PD60U / PX6U / PX60U / PX600U
PD50U / PX50U / PX500U :


* Hold down the {VOL -} button ON THE PLASMA TV.
* Press the {RECALL} button 3 times on the remote.
* The Service Menu will be displayed.
* Use {1} {2} on remote to navigate main menu items.
* Use {3} {4} on remote to navigate sub-menu items.
* Use {VOL+} {VOL -} on remote to change item value.
* Write down all values before changing
Once a value is changed, THE CHANGE IS MADE.
* Power off to exit service mode and save
OK.

I seem to recall a sub-menu setting having to do with "auto shut off" or something like that.

My receiver is packed up, ready to take to Fry's, or I would find that submenu for you.

Chances are if The Receiver only has sound in Stereo Direct Mode and all surround modes and Sub out are Inop the DSP (Digital Signal Processing) Card is most likey defective. These boards are not available from marantz (D&M Holdings) and must be Component level repaired which usually is not cheap. If Only the Sub out is not working check setup to be sure sub woofer is set for on. Also If On Screen setup menu does not appear on video monitor Unit may need to be Reset manually which entails discharging a Capaitor on main P.C.B Contact [email protected] for details

May not necessarily be the out put, discontect the sub from the receiver and see if it still makes a hum, Making sure that you turn auto on, off on the sub woffer.
If it still makes a hum, then you have a earthing problem, you can get a earth filter put on your internal wiring in your home, or you can remove the earth pin on your sub woffer