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!

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All posts are presented here for informative, historical and educative purposes as applicable within fair use. NOTHING HERE IS FOR SALE !

Tuesday 19 March 2019

AKAI PT4250AX/SMS REAR PROJECTION TV - HOW TO ENTER SERVICE MODE - W/B ADJUST - LENS FOCUS ADJUSTMENT - BEAM ALIGNMENT

AKAI PT4250AX/SMS Rear Projection TV - HOW TO ENTER SERVICE MODE - W/B ADJUST - LENS FOCUS ADJUSTMENT - BEAM ALIGNMENT

SERVICE MODE
  • Turn on the TV, and then select "STANDARD" on the picture adjustment mode.
  • Turn off the TV (STAND-BY).
  • Enter the service mode by pressing the remote control keys in the following sequence : [MUTE => 1 => 8 => 2 => POWER]
Initial SERVICE MODE DISPLAY
Service Mode Control Keys
  • Direction keys ▲/ ▼ => Item Selection by Moving the Cursor
  • Direction keys ◄/► => Data Increase/Decrease for the Selected Item.
  • Press the Add key to exit.
W/B [White Balance] ADJUSTMENT
  1. Select the "STANDARD" Video Mode.
  2. Input 100% white pattern.
  3. In the stand-by mode, press the remote-control keys in the following sequence: [MUTE => 1 => 8 => 2 => POWER]
  4. Warm up the TV for at least 30 minutes.
  5. Input a 10-step signal.
  6. R-cut off, B-cut off, and G-cut off by pressing the ▲▼ / ◄► keys.
  7. Adjust the low light with viewing the dark side of the screen.
  8. Select R-drive, G-drive, and B-drive by pressing the ◄► / ▲▼ keys.
  9. Adjust the high light with viewing the light side of the screen.
  10. If necessary, redo screen adjustments and 6~9.
  11. Press the Add key to exit.
Lens Focus Adjustment
  • Set the Screen to "STANDARD". (Contrast : 100 / Brightness : 50)
  • Set the pattern to Crosshatch.
  • Adjust the electric focus before beginning.
  • Adjust the DY tilt (TILT) before beginning.
  1. Loosen the lens screw for easier adjustment.
  2. Press Mute, 1, 8 and 3, sequentially to enter Convergence Mode.
  3. Display only the Green pattern by using the +100, 0, and Previous Channel Keys in order to turn the R, G, and B patterns On/Off respectively.
  4. Turn the Green Lens clockwise/Counterclockwise to adjust for optimum status.
  5. (Repeat if unsuccessful, varying the VR of the front Focus Pack.)
  6. Perform steps 1~3 for the R and B Lenses. [Note: Green determines picture quality; pay close attention for exact adjustment]

BEAM ALIGNMENT
  • Select the "STANDARD" Video Mode.
  • Warm up the set at least for 10 minutes.
  • Enter the Convergence mode by pressing the remote control buttons in the following sequence. [MUTE => 1 => 8 => 3]
  • Set the Beam Alignment Adjustment CY to Zero magnetic field area.
  • Press the 7- digit button for a while, on the remote control, and a vibrating dot-pattern appears.
  • Adjust the Focus-pack VR for defocusing.
  • Mute the other patterns (R/B) other than G-PATTERN. (Use "+100" / "PRE-CH" Key on the remote control.)
  • Adjust the 2, 4 polarities of VM-COIL as shown in figure below.
  • Adjust the G-Focus until any light around the core disappears.
  • Adjust G-Focus so that the surrounding flash can disappear from the spot.

  • After G-Focus adjustments are complete, adjust R-Focus as above procedures.
  • The B-CRT adjustments can be omitted because the variance of beam focus is small. (Only Vm-coil is mounted.)
  • Adjust the Focus-pack VR for fine focusing.
  • Press the 7- digit button for a while, on the remote control, and the mode changes to the Convergence Adjustment mode.
  • Press the "S.MODE" Key on the remote control to return to normal viewing.
Since this RPTV uses Samsung Technology, remote control to Samsung is used to adjust the parameters.
REMOTE CONTROL KEY FUNCTIONS IN CONVERGENCE MODE
Posted By: FRANK at 03:17
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