REPAIRING AND NOT THROWING AWAY

REPAIRING AND NOT THROWING AWAY

Richtige Fernseher haben Röhren!

Richtige Fernseher haben Röhren!

In Brief: On this site you will find pictures and technical information about Service Modes, Circuit Diagrams, Firmware Update procedure, Disassemble procedure, Universal remote control set-up codes, Troubleshooting and more....

If you go into the profession, you will obtain or have access to a variety of tech tips databases HERE IT IS Master Electronics Repair !.

These are an excellent investment where the saying: 'time-is-money' rules. However, to learn, you need to develop a general troubleshooting approach - a logical, methodical, method of narrowing down the problem. A tech tip database might suggest: 'Replace C536' for a particular symptom. This is good advice for a specific problem on one model. However, what you really want to understand is why C536 was the cause and how to pinpoint the culprit in general even if you don't have a service manual or schematic and your tech tip database doesn't have an entry for your sick TV or VCR.

While schematics are nice, you won't always have them or be able to justify the purchase for a one-of repair. Therefore, in many cases, some reverse engineering will be necessary. The time will be well spent since even if you don't see another instance of the same model in your entire lifetime, you will have learned something in the process that can be applied to other equipment problems.
As always, when you get stuck, checking out a tech-tips database may quickly identify your problem and solution.In that case, you can greatly simplify your troubleshooting or at least confirm a diagnosis before ordering parts.

Happy repairing!
Today, the West is headed for the abyss. For the ultimate fate of our disposable society is for that society itself to be disposed of. And this will happen sooner, rather than later.

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..............The bitterness of poor quality is remembered long after the sweetness of todays funny gadgets low price has faded from memory........ . . . . . .....
Don't forget the past, the end of the world is upon us! Pretty soon it will all turn to dust!

©2010, 2011, 2012, 2013, 2014 Frank Sharp - You do not have permission to copy photos and words from this blog, and any content may be never used it for auctions or commercial purposes, however feel free to post anything you see here with a courtesy link back, btw a link to the original post here , is mandatory.
All posts are presented here for informative, historical and educative purposes as applicable within fair use. NOTHING HERE IS FOR SALE !

Wednesday, 20 February 2019

TOSHIBA 28MW7DB 28MW7DG SERVICE MODE AND ADJUSTMENTS - SELF DIAGNOSTIC FUNCTION



TOSHIBA 28MW7DB 28MW7DG SERVICE MODE AND ADJUSTMENTS - Self Diagnostic Function 

ENTERING SERVICE MODE


  • Press the 'Mute' button on the remote control. A  mute symbol will be appeared.
  • Press 'Mute' button again and Hod it.
  • While pressing the "Mute" button, press "Menu" button on the front panel of the TV.
  • Will display the adjustment Menu.
  • Press 'Mute' button on the TV. "S" will be displayed on the upper right corner of the screen.
KEY FUNCTION IN THE SERVICE MODE
  1. A single horizontal line ON/OFF >> [-/---] button on the remote control or 'Power' button on the front panel of the TV.
  2. Test signal selection >> 'Power' button on the remote control.
  3. Selection of the adjustment item >> Channe Up/Dn button, either on the remote control or at the TV.
  4. Change of the data value to selected item >> Vol (+/-) either on the remote control or at the front panel of the TV
  5. Adjustment menu On | Off >> Menu button.
  6. Initialization of memory >> Call + Channel [Up] button on the TV. (Never try to perform initialization unless you have been changed the memory IC) 
  7. Reset the count of operating protect circuit to "00" >> Call + Channel [Dn] button on the TV.
  8. R-CUT selection >> 1 button.
  9. G-CUT selection >> 2 button.
  10. B-CUT selection >> 3 button.
  11. CNTX selection >> 4 button.
  12. COLC selection  >> 5 button  ----- Color thickness correction.
  13. TNTC selection  >> 6 button ----  [Note: May display differently depending on the setting of the receiving color system.  COLP = PAL |  COLC = NTSC | COLS = SECAM]
  14. Test Audio Signal On/Off  >> 8 button.
  15. Self diagnostic display On/Off >> 9 button.
SELECTING THE ADJUSTING ITEMS
  • Every pressing  of the 'Channel Up' button in the service mode, changes the adjustment items.
ADJUSTING DATA
  • Press of 'Volume ( +/- )' button will change the value of the data in the range from [00H to FFH].  The variable range depends on the adjusting item.
TO EXIT SERVICE MODE
  • Press the "Power" button to turn OFF the TV once.
INITIALIZATION OF MEMORY DATA OF QA-02.
  1. Enter the 'Service Mode' and select any register item.
  2. Press and Hold the 'Call' button on the remote control, and press 'Channel Up' button on the TV.  The initialization of QA-02 is completed.
  3. Check the picture carefully.  If necessary, adjust any adjustment item.  
  4. Perform "Auto Search Memory" function to make sure it works correct.  
TEST SIGNAL SELECTION
  • Every pressing of 'Power' button on the remote control changes the built-in test patterns on the screen in 'Service Mode'.  [Toggle between NTSC signals (14 patterns) => PAL signal (14) patterns => signal Of =>]
SELF DIAGNOSTIC FUNCTION
  1. Press (9) button on the remote control during display of Adjustment Menu in the Service Mode.  The diagnosis will begin to check if interface among ICs are executed properly.
Diagnosis Screen
==================================

                    <SELF CHECK>

 2390****
POWER      : 00
BUS LINE  : OK
BUS CONT: OK
BLOCK      : UV  V1  V2  QV1
==================================
  • 2390**** is part number of microcomputer.
  • Operating number of the protecting circuit  --- '00' is normal.  When indication other than '00' over current apts to flow, and circuit part may possibly be damaged.
  • BUS LINE CHECK: 'OK' is normal.  [SDA 1-GND = SDA-GD short circuit.] [ SCL 1-GND = SCL-GND short circuit] [ SCL 1-SDA 1 = SCL-SDA short citcuit.]
  • BUST CONT ---'OK' is normal. (When indication shows "QoooNG", the device with the number may possibly be damaged.)
  • BLOCK: (UV=TV reception mode.  V1=Video 1 input mode.  V2=Video 2 input mode]
Others

Indicated color of mode now selected: Green and Red.
Indicated color of other items: White.

Green: Normal.
Red: The microcomputer operates to provide judgement of no video signal.  The red color is still indicated though the signal is input, failure may exists in input signal line including QV 1

QV 1 :  In the case of indication Green = Normal
             In the case of indication red  with input signal = Failure may exist in output line including  QV 1.

  • In the case that the 'Power' indicator is blinking with intervals of (0.5) seconds, means the protecting circuit is operating, and circuit component may possibly be damaged.  Check related components.
  • In the case that the 'Power' indicator is blinking with interval of (1) second, protection circuit does not operate, but a part of Bus Line does not operate normally.  Check bus Line.






ELECTRICAL ADJUSTMENTS.



ITEM
ADJUSTMENT PROCEDURE
Focus adjustment
# Enter the Service Mode and select any register item.  # Press TV/Video button  on the remote control until the balck corss bar pattern appears on the screen.  # Asjust Focus control  in the line output transformer (Top One) for well defined scanning lines on the picture screen.
Sub-Brightness [BRTC] [Note:  Constrict picture height until the vertical retrace line appears adjusting the item HIT (Height)]
# Set contrast to minimum and brightness to center by adjusting user controls. # Set the TV in service mode to get white cross bar of inside pattern.  # Select BRTC , and adjust the Volume Up/Dn to reduce the value, so that white portion of inside pattern slightly light.  # Adjust Vol Up/Dn to increase the data value of BRTC, and set it just before the difference between the belt of the vertical retrace, and the border of black portion of inside pattern is visible.  After that, return vertical height  and contrast.
Horizontal position adjustment [HPOS]
# Set the TV in service mode and get black or white cross-bar signal with video button on the remote control.  # Select either HPOS (Horizontal Phase) or VPOS (Vertical Phase) with Channel Up/Dn buttons, and adjust the horizontal or vertical picture position  to the center of the screen with Volume Up/Dn buttons.
Vertical amplitude adjustment.  [HIT]
# Set the TV in service mode, and get black or white cross-hatch signal with video button on the remote control.  # Select HIT with Channel Up/Dn buttons and adjust the vertical amplitude by using Vol Up/Dn buttons, so that the first bar on cross hatch signal touches the edge of the screen.
White balance adjustment.
  • Cut-Off adjustments
  • Drive adjustments
# Set contrast to ‘40’ and brightness to ‘+20’ by picture control.  # Set TV in Service Mode and get the inside W/B adjusting signal with video button.  # Select R-Cut, G-Cut and B-cut with Channel Up/Dn buttons to set individual values to initial reference data with Volume Up/Dn buttons on the remote control.  # Press [-/---] button on the remote control and rotate screen VR to get a slight horizontal line on the screen.  For every pressing of [-/---] button provides Horizontal line picture and normal picture alternately.  # Press [-/----] button to release horizontal line picture, and select the tow other colors which did not light in the above step with Channel Up/Dn buttons.  Then tap Volume Up/Dn buttons so that three colors slightly light in the same level.  *To correct white balance in light area, select GDRV with Channel Up/Dn buttons to adjust.  ** To correct white balance in dark area, perform fine adjustment of R-Cut, G-Cut and B-Cut.
Posted By: FRANK at 02:51
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