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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Monday 4 February 2019

SAMSUNG CT331HBZX CRT TV [NTSC] - HOW TO ENTER SERVICE MODE, ADJUSTMENTS AND CIRCUIT DIAGRAM

CT331HBZX Samsung CRT TV [NTSC] - How to enter service mode, adjustments and Circuit diagram


Applicable to Samsung CT331HBZX- CT501EBZX - CT331EBZX - CT501HX - CT331HBX - CT5066BZX - CT331HX - CT5038ZX - CT3366BZX - CT3338ZX [Chassis K15A]
Used ICs: KA2131(Vertical amp) – KA350765R(SMPS-STR) – KA21638(chroma-jungle) – Z8933412PSC(Micom) – 24C020(Memory) – LA4425(audio output amplifier)
FBT OPTION
14” = AA26-300005H, 20” = AA26-300005F, 21” = AA26-30005F

Service Mode Menus
Since there are no VRs in the K15A chassis, all adjustments after parts replacement must be done in the Service Mode. Service Mode adjustments are necessary when either the EEPROM (IC902) or the CRT is replaced.
Entering the Service Mode
Press the following transmitter keys while in STAND-BY mode:
MUTE > 1 > 8 >2 > POWER
“Factory Mode Menu” is displayed.
Enter Service Mode using the Volume + / - keys.
Select a mode to be adjusted, using the channel down key.
Change the data with “Volume + / -- “ keys.
Return to the Service mode by pressing MENU.
Return to the Factory mode via the MENU key.
Press POWER to enter the Stand-by mode.
SMPS and deflection circuit diagram [Click on the pictures to zoom in]
Chroma jungle schematic
Micom schematic
PWB
Adjustment in Option Mode
This adjustment is necessary whenever the EEPROM is replaced. Input data (as marked on the back cabinet).
Select “SET OPTION” by pressing the Channel “Dn” key twice.
Press the Volume + / -- keys to enter the set Option mode.
Press MENU to go back to the factory mode.
Select RESET with channel “Dn” key.
Press volume + key. [Power Off].
Service Mode Adjustments
1. The Pattern Adjustment is done only in the factory. Do not attempt to readjust it.
2. Refer to 4-2 for other adjustments.
3. Set OPTION data.
Service Mode Adjustment Ratings
General Alignment
Usually, a color TV needs only slight touch-up adjustment upon installation. Check the basic characteristics such as picture height, focus and a horizontal and vertical sync.
Observe the picture and check for good back and white details. There should be no objectionable color shading: If color shading is present, demagnetize the receiver. If color shading persists, perform purity and convergence adjustments.
Power Supply Check
A: Power plug is connected; “Stand-by” mode
B: Power On when “Power ON” button is pressed
C: Power On by FBT Each supply is marked on its lead-in wire.
Fail Safe Circuit Check (FS) (OPTION)
1. The fail-safe check must be the final step in servicing. 2. Turn the power switch ON and adjust customer controls for normal operation. 3. Temporarily short pin X to pin R on the main board (RX06, RX04) with a jumper wire.  Raster will disappear. 4. The TV must remain in this state even after removing the jumper wire. This shows that the failsafe circuit is working properly. 5. To recover picture and sound, temporarily turn off the TV and allow the failsafe circuit more than 30 seconds to reset. Then switch power ON to produce normal picture and sound.
IC902 Replacement
1. When IC902 is replaced, all values are reset to “Initialized MICOM Data” and readjustment is necessary.
2. Press the POWER button 10 seconds after plug-in.
RF-AGC Adjustment
1. Input a PHILLIPS pattern.
2. Set the input signal to 60 dB.
3. Enter into the AGC in the service mode.
4. Adjust AGC until color bar noise disappears.
Sub-Contrast Adjustment
1. Input a gray scale pattern. Use a pattern generator (PM5518).
2. Short D208 to switch off the ABL feed-back.
3. Check CN201 R-OUT with an oscilloscope.
4. Set RC, BC, GC data to 0 in the Service Mode.
5. Adjust SCT to 2.40 ± 0.1Vp-p
6. Remove the short across D208 and restore ABL.
Sub-Tint Adjustment
1. Input a rainbow pattern.
2. Check CN201 B-OUT with an oscilloscope.
3. Adjust STT in the service mode until the 6th peak is the highest and the 5th and 7th peaks have equal heights.
Sub-Color Adjustment
1. Do sub-color adjustment after the SubContrast and Sub-Tint adjustments.
2. D208 should still be shorted. The ABL should still be switched OFF.
3. Input a color bar pattern. Use a pattern generator (PM5518).
4. Check CN201 R-OUT (use an oscilloscope).
5. Ensure that the RC, GC and BC data are 0.  BG are 140 and GG should be 90.
6. Adjust SCR to 2.4 ± 0.1Vp-p (black and red levels).
7. Remove the short across D208 and restore ABL.
White Balance Adjustment
LOW-LIGHT ADJUSTMENTS
1. Input either a lion head or “pure white” color pattern.
2. Operate the receiver for 30 minutes.
3. Check the data in the service mode:
RC, GC, BC are 0 and SB is 16; Steps BG are 90 and GG are 140.
4. Enter the horizontal line mode by pressing the MUTE key.
5. Adjust the screen VR on the FBT until a dim colored line (red, green or blue) appears on the screen.
6. After pressing the MUTE key, go to RC,BC or GC with channel UP|Dn, keys. After putting a dim colored line (red, green or blue) in the horizontal line with MUTE key, adjust color with volume Up|Dn , keys.
7. Exit the horizontal line via the MUTE key.

HIGH-LIGHT ADJUSTMENTS
1. Input a high-light pattern
2. Adjust GG,BG in the Service Mode.
3. Recheck in low light.
Sub-Brightness Adjustment
1. Input a Toshiba pattern.
2. Warm up the receiver for 10 minutes.
3. Enter the Service Mode and set SB to the point where the 5th point is brighter in the gray scale.
Vertical Size Adjustment
1. Input a lion head pattern.
2. After the vertical center adjustment, enter into the service mode.
3. Adjust VA so that the each top and bottom of the screen is 4.0. If the top and bottom values are different, adjust VA so that the sum of the two values is 8.0.
Horizontal Size Adjustment
1. Receive a lion head pattern.
2. Enter into the service mode.
3. Adjust HS to symmetrized right and left
When CRT Is Replaced
Do the following adjustments after the basic purity and convergence adjustments.
1. White Balance
2. Sub-brightness
3. Vertical Size
4. Horizontal Size
5. Fail safe (should be the final step).