Did you know you can screw Future Shop, Circuit City and other
  electronics stores TV sales departments with just a few keypresses?

  Most TVs sold today have digital service menus, hidden and completely
  unknown to the consumer.  Not quite an easter egg, because these
  'features' are well known to TV servicemen.  And heaven knows, I'm
  about to do their industry a favor by publishing this file.

  Once you are in a service menu you can do all kinds of things to the
  TV that used to need a screwdriver and the cover off.  You can turn
  the Horizontal Hold way over until the TV shuts down - requiring a new
  memory chip to correct.  You can totally de-align the tuner.  You can
  change the colour temperature so it looks like an old fashioned sienna
  photograph. You can put its user menus in a foreign language, and on
  some models that can't be undone.  Oftentimes, your changes can only
  be corrected by a costly visit from a senior level technician, someone
  the store isn't likely to have on staff.  Do this to 8 or 10 TVs and
  your actions will cost the store a LOT of money.  The manufacturer and
  distribution network also must bear the costs of this, unless of
  course you're caught.

  Here are some TVs you can screw with:

     RCA and G.E. (most models after '94): Turn the TV on.  Hold down MENU
     and hit POWER and VOL+.  Now you're in the service mode, looking at
     parameter 0.  It will say:

              P00     V00

     Use the VOL+ key to change the value (V number) to 76.  This has to be
     done before you can do anything else; it's sort of a password.

     Once P00 is set to V76 you can use the Channel + and Clannel - buttons
     to select from the first 12 parameters.  P13 is another password - set
     to 77 to get higher parameters.  Depending on the model, another one a
     couple of dozen parameters up will require a password of 78.  This
     varies by model but you will know when you have found it because you
     won't be able to advance past it.

     The first parameter, P01, is probably the quickest and easiest to
     work.  It is the Horizontal Frequency control.  When you select it,
     the TV will lose horizontal sync.  Turn it all the way down or all the
     way up with VOL- or VOL+ and then get out of setup (if the TV hasn't
     shut itself off by then) with the power button.

     Here are the parameter tables:

     P00   Password (Must set to 76)   P14  PLL Tuning
     P01   Horizontal Frequency        P15  4.58 MHz Trap
     P02   Horizontal Phase            P16  Video Level
     P03   EW DC (Width)               P17  FM Level
     P04   EW Amplitude                P18  B+ Trim
     P05   Vertical DC                 P19  RF AGC Chan 6
     P06   Vertical Size               P20  RF AGC Band 1
     P07   Red Bias                    P21  RF AGC Band 2
     P08   Green Bias                  P22  RF AGC Band 3
     P09   Blue Bias                   P23  D-PIP Chroma
     P10   Red Drive                   P24  D-PIP tint
     P11   Green Drive                 P25  D-PIP bright
     P12   Blue Drive                  P26  D-PIP contrast
     P13   Password (Must set to 77)   P27  Factory Tint

     P28 Password (Must set to 78)

     P100-156 - Tuner alignment parameters.  If you fuck with these, the
     tuner will have to be aligned by a professional.


     PANASONIC:

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

     First, select the SET-UP icon and select CABLE mode.

     Then, select the TIMER icon and set the SLEEP timer for 30 minutes.

     Next, press the ACTION button twice to get out of the menus.

     Now, change to channel 124.

     Then, adjust the volume to minimum (0).

     You're almost there - Hit the VOL down button on the TV itself (not on
     the remote) and a red "CHK" should appear in the upper corner.

     Now, if you 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 firld 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 remote
        cimultaneously for at least 2 seconds.  The TV will momentarily
        shut off and then comes back on.


     JVC:

     Newer ones with the full colour menus...

     Go into the menu, select CLOCK SET, and you will get the clock set
     menu.  Set the clock to 3:21 AM.  As soon as you select "Start Clock",
     you see a flashing "THANK YOU".  WHILE THIS IS STILL FLASHING hit MUTE
     then UP/DOWN.  You will then be in a service menu which will let you
     change all kinds of neat things.

     The service menu on new JVC televisions is quite self explanatory, so
     I will not include a walkthrough here.


     ZENITH:

     I think this might work on Goldstar TVs as well, since both Zenith and
     Goldstar are the same company, LG Electronics.

     Hold the MENU button.  The menu will come up and then after a few
     seconds will go away.  Now let go of the MENU button and enter

                9   8   7   6   Enter

     You will get a service menu that varies widely depending on model, so
     I won't include a walkthrough here.  The ones I tried were fairly
     self-explanatory.