Philips 21 inch CRT TV – Service mode, factory mode, fault detection, Schematic

Used ICs: TDA98XX, TDA486X, W6554A (STR), DM837X, TDA9842AJ, TDA98XX

[If you feel any difficulty to see the diagrams, please take a magnified printout. See this post by desktop computer.]

Service Modes, Error Codes, and Fault Finding

This chassis does not contain a specific Service Mode. Service and Alignment of the TV set can be done via the Factory Mode by the service technician.

Power on Failure
Check whether the power supply is working properly and whether the values of voltages normal. If those are correct, check line transistor and transformer are working properly and check fore or back line for defects.

Horizontal Deflection Transistor Defective: No Picture, No Sound.

To find the fault for a defect with horizontal deflection transistor check the following items:
• Over voltage to breakdown.
• Over current to burn.
• Horizontal frequency too low or very high.
• Horizontal drive inefficient.

Picture Interference
• Check if the signal line contact is good.
• Change Tuner if is necessary.

Can't find any TV program
 Check the closed circuit from tuner to picture decoder IC to detect whether there are defective components. 

Check whether the resistance of R117, R118, R203 and R204 has increased which also could cause the problem.

No Good Picture or Double Image
Check the correctness of the signal from IF1/IF2 to Q101 and relevant circuit. 

In this case the problem can be Q101 and/or SAW101

Picture not or incorrect Colored
• Check the circuit from IC201 to R.G.B. three gun circuit.
• Check the IC soldering and relevant circuitry on physical damage or check for defective capacitors.

Picture with Horizontal Bright Line and Sound
Check both supply voltages of vertical IC301 and relevant circuitry for correctness. Also check the vertical synchronizing signal from IC201

Remote Control Malfunction
Check the voltage on pin 64 of IC201. 

The normal value should be 5.15 V. 

If this is correct check front control panels soldering connections. 

If can't be solved, check the remote control, crystal or transmitting diode of the remote control are in good condition.

No Sound
Check power supply of sound IC (IC402) and relevant circuitry (not exclude IC402 to be defective) or change speakers

Poor Sound Quality
Check the sound system after searching the channel which should set at DK, I or AUTO. 

If still has problem, check accompany board circuit on chassis good or not.

Main Voltage Adjustment
In order to adjust the main voltage, connect a voltage meter to the cathode of diode D610, and adjust VR601 to a voltage of 110 V ±0.3 V

To Put the set in its MENU mode (factory mode) as follow

Rf AGC Voltage Adjust
1. Provide a 475.25 MHz, 60 dB half colour bar signal.
2. Enter factory mode and press key 4.
3. Measure tuner AGC point voltage, adjust AGC item till the voltage is 2.4 V, or till picture noise just disappears.

Focus Fine Adjust
1. Provide a cross-hatch pattern signal.
2. Set state to dynamic.
3. Adjust flyback transformers Focus knob till picture is clear.

Screen Voltage Adjust (Key 0).
1. Set picture to “Standard” mode, without signal input.
2. Enter factory mode and press key ”0”. There will be a level bright line displays

Adjust flyback transformers Screen knob till the level bright line just can be seen, press PROG+ and turn to other factory menu.

Horizontal Adjustment (key 1)

1. Provide a 50 Hz monoscope pattern. Put the set in the MENU mode. Press key 1 to enter factory mode.

2. Adjust 5HSH (for 60 Hz picture, its is 6HSH) to set picture horizontal centre to CRT horizontal centre.

3. Provide a 60 Hz monoscope pattern. Put the set in the MENU mode. Press key 1 to enter factory mode.

4. Adjust 6HSH to set picture horizontal centre to CRT horizontal centre.

Vertical & YUV/RGB Horizontal Adjust (key2)

1. Provide a 50 Hz cross hatch signal, set TV to standard mode. Adjust 5VSL so that half picture of the pane cross appears. The picture’s vertical line is just at the bottom of the half picture. Adjust 5VSL to make the centre of the picture’s vertical line and the kinescope are in superposition.

2. Adjust 5VAM to obtain picture’s vertical re-display ratio more than 90%.

3. Provide a 60 Hz cross hatch signal, do step 1 and 2 again to adjust.

4. If necessary, fine adjust above items.

5. Provide a 50 Hz RGB or YUV cross hatch signal, set the TV in the standard mode, adjust 5RGH till picture horizontal centre is at the CRT centre (optional).

6. Provide a 60 Hz RGB or YUV cross hatch signal, set the TV in the standard mode, in the factory menu, adjust 6RGH to make the pane cross vertical center at the center of the screen (optional).

OSD Position
1. Menu OSD position adjustment: Provide a 50/60 Hz cross hatch pattern. Put the set in MENU mode. Press key 2 to enter the factory mode. Adjust 5VOF/6VOF and HOF item, to obtain menu OSD at the centre of CRT screen.
2. LOGO position adjustment: Provide a 50/60 Hz cross hatch pattern. Put the set in MENU mode. Press key 7 to enter the factory mode. Adjust XMIN, XMAX, YMIN and YMAX, to obtain LOGO at the centre up to 1/3 of CRT screen.
3. Teletext OSD position adjustment: Provide a red signal in the standard mode. Press key 7 to enter the factory mode.
Adjust TXMI and 5TYM/6TYM to obtain index at the centre of screen.

White Balance Adjustment (key 3)
Normally, this chassis can auto adjust white balance, but for some CRTs it a necessity to adjust white balance carefully by hand. Set Brightness and Contrast at normal status, provide a greay scale test pattern and from the MENU mode press key 3 to enter the factory mode. Set WPR at 31, adjust WPG and WPR to obtain white balance.

To Enter Factory Mode    Click on the pictures to magnify

Circuit diagram (Schematic)

E2PROM Initializtion (key 8)

An empty or used E2PROM can be used for servicing. 

The following steps have to be passed through to initialize the E2PROM.
While in the MENU mode press key 8 to enter the factory mode.
Now enter the initialization menu by pressing the < / >.

The set shows the OSD ”INIT BUSY” on screen, 5 minutes later, the text “BUSY” disappears. Now power OFF and ON the set. 

This finalizes the initialization.

Function Settings (key 5)

1. While in the MENU mode press key 5 to enter the factory menu.
2. The Logo setting is used when powered on or no signal.
Press MENU in the factory mode to enter the compile mode, there are to rows. 

The first can set the customer’s name etc. 

The second row is intended to display the customer’s e-mail, telephone etc. 

Press L / R  to select the character to edit. Use keys Up / Dn buttons to choose the character.
Press MENU again to exit this view.
3. Set values for Option 1 to Option 8