CRT test

HOW TO CHECK A PICTURE TUBE

    
It is very easy to check the emission of the cathodes of a color picture tube. Assuming all other circuit functions right, including LOT [Line output Transformer] and video output section. There is proper screen voltage; focus voltage and EHT [Extra High Tension].
      Locate the three cathode points on the base card, usually marked as Gk, Bk and Rk. Keep the brightness, contrast and color control to zero position. Take a wire of suitable length, say 50cms or so tie or clip its one end to TVs chassis [negative]. Take one resistor of value 100K 1W, tie its one end to the wire, thus one end of this resistor is now connected to negative chassis with wire and the other end of it is free now.
      Hold this resistor with some electrically nonconductive material [using hand gloves will be better]; switch on the TV, wait a minute or so to get it warm up. Just make an intermittent touch at each cathode of the picture tube base card soldering.
     For each intermittent touch will give you a color flash at screen of the respective cathode. For example, when you touch on the Rk cathode, will give a red color flash on the screen. Similar effect will give for the other two cathodes.  If any one does not get the respective color flash on the screen, check the CRT base-connecting socket for any fault with its contacts to the picture tube pin first.  Replace the CRT base socket is recommended before confirming the fault.
    Never hold it for long duration of time. Only intermittent touch should be done. This process can be used for checking cathode emission of any type of Cathode Ray Picture tubes.

HOW TO ENTER SERVICE MODE TO PANASONIC - CT SERIES TELEVISIONS.

APPLICABLE TO:


PANASONIC: CT-20R6E_CT-20R6CE_CT-20D11CE_CT20D11DE_CT-2006SE_CT20G6E_CT-20G6DE_CT-2016SE.


                                      TO ENTER SERVICE MODE


     All times, if minor adjustments to be done to the electronic controls, the method of entering service mode without removal of the cabinet back is as follows using the remote control.

• Select the "Setup" icon and select "Cable" mode.
• Select "Timer" icon and set sleep time for 30 minutes.
• Press "Action" button twice to exit menus.
• Tune to channel [124].
• Adjust "Volume" to [0].
• Press "Volume <" button on the "Receiver.  Red "CHK" appears in the upper corner.

     While the 'CHK" is appeared on the left top corner of the screen, pressing the Action & Volume Up buttons on the receiver simultaneously will toggle between  modes.  Red 'CHK' for service, and Yellow for Aging.  

• Press the 'Power" button on the remote control to select one of service adjustment modes.

1. B => Service VCJ SUB-DATA adjustment.
2. C => Service VCJ CUT-OFf adjustment.
3. S => Service options [Picture adjustments]
4. M => Service MTS adjustments.
5. P => Service VCJ adjustments.
6. X => Service AFC adjustments.
7. "CHK" => Normal operation of Channel Up,Dn or Volume '<-  ->'

TO EXIT SERVICE MODE

     Press "Action" and "Power" on the receiver simultaneously for at least 2 seconds.  The receiver exits service mode.  It momentarily shuts OFF then come back on tuned channel '3' with a preset level of sound.  Any programmed channels, channels caption data and some other used defined setting will be erased. 

Registers marked as 'Fixed"in the following are Factory Preset.  Do not change these values.

• Press Power button on the remote control to select the service adjustments.
• Press Ch Up & Ch Dn button on the remote control to select one of the available service adjustments.
• Write down the original value set for each address before modifying anything.  It is easy to erroneously adjust the wrong item.
• Press Vol Up/Vol Dn button on the remote control to adjust the data value to selected item. 

     Some adjustment modes may not be available in some models depending on available options.