CRT Monitor Service Guide

CRT Monitor Service GuideCRT Monitor Service Guide

Damage that often occurs on CRT monitors below is a continuation of my article that I’ve posted some time ago. For those of you who have never read please click here. CRT Monitor Service Guide

Flyback working but the screen is dark.
• Check the line heater (filament tube / tubes), usually crack solder.
• Check the G2 line (usually cracked solder)
• Replace C ceramic high voltage (1600-2000V) in G2 which serves as a further discharge. C. This does not seem damaged but had in fact changed its capacity. It’s on the block RGB / video block.
• Tubes damaged / weak. The best solution is replaced with another tube is OK.

Samsung 14 synmaster / SPC 14 and 15 often damaged in DIODE H size.

ACER 14 often have cracks in the solder trafonya, so it looks dead.

Horizontal line in the middle of the screen:
• There was a split in the Vertical
• Vertical IC is defective.
• Vertical IC Vcc is not entered (R fuse end) or vertical output power supply is damaged.

Screen can not be full when all the normal components
Yoke is damaged, replace

Screen narrows to form unsymmetrical
Broken Yoke, replace the tube

There is no clear picture or color interfere in any screen color of the rainbow:
Check the degaussing PTC connection, usually crack.

ACER 14 which replace the normal FBT for a resolution of 640×480, 800×600 but for the dark.
Raise the B + voltage to 110 Vdc

VISION 15 rolled up the screen below.
Re-solder the front panel and the vertical.

Brightnes unstable (sometimes light sometimes dark)
Check the connection of video ICs
Check the line G1.

After changing FBT, Horizontal become hot quickly.
Lower voltage changing AFC AFC with FBT with 2-3 turns in FBT. If it is hot try reducing the number of AFC loops.

Excessive AFC produces a high voltage B + is also causing a rapid Horizontal heat, and input B + II from the IC to terprotek.
Input B + II is the result of IC Vcc 5 Vdc as input to the FET or Transistor B + II.

All the normal component, but the monitor stays off
Horizontal lines Tr freelance basis. Turn on the monitor and check the AC input voltage transformer syncrone horizontal, if not then the serial link to the rear. These transformers have Vcc 12 V from the power supply Vcc is usually combined with the vertical. Please check this 12 V voltage. If no voltage, means there is damage to the IC program that serves triggering Transistor Horizontal syncrone. If the voltage of 12 V is not listed, if the measuring path will produce a high voltage of approximately 90V transistor colector horizontal lines. CRT Monitor Service Guide

GTC FUTURA 14 is OFF, the horizontal and FBT OK.
Elco check the size of UF 1000/35 v power supply in vertical section, if the heat at the time the monitor is turned on, the elco is damaged, replace it. (No visible damage)
Elco is defective and causes a voltage Vcc Tr Hor Vertical Sync to be down, but no longer 12 v 9 v Only so can not be to run a series of vertical and hor sync. Characteristics if G2 is increased, then the screen will be white horizontal lines in the middle of the screen.

AOCA 14 dark screen.
Check the heater voltage (6v), if true means the tube is weak.

Display the picture looks washed out on the screen
Elco RGB is old age so that the liquid is dry, the question is elco elco with a high voltage of about 100-160 v with small farad size, about 1 UF. Elco before the IC can be a video, which can also be Upholstery Video Tr. Try replacing them with new ones. Also check elco G1, may also occur in this component damage.

Model B + II
Some use the FET
Some use the Tr
The use of Tr using the following method:
• At 640×480 Frequency: B + B + voltage of normal use of the PS
• At 800×600 Frequency: In addition to the additional normal B + voltage of the transistor which is triggered by the base input voltage 5 v output is the result of the IC program. This produces an additional voltage transistors so that the voltage becomes mixed with the B + voltage is normal (double) and generate a new B + voltage of about 110 V
In the 1024×768 • Frequency: the principle of cooperation with IC output voltage is only 800×600 which is the base input voltage Tr up to produce a mixture of about 125 V
• If a resolution of 640×480 5v output voltage IC will not appear.

If you replace the FBT B + II TR, then the out put TR B + II added a series of turns in the direction / counter-clockwise by the number of loops adapted to the normal B + voltage at high freq. Pin 1 is connected with the diode have Tr B + II, and again got the pin 1 + normal B pathway. It is intended to obtain the desired voltage.

Samsung 14 frequently damaged parts of the tube.

Samsung PS 14 are dead his
Caused by a small elco in the power supply so that if the heat could damage the flame, replace the elco.

If G2 is broken (the brighter the screen, the brightness tisak stable)
Remove the original G2 FBT, replace with the following sequence:
FBT colector searahkan with diode watt in small / large voltage is then scaled by R ohm size of between 300 Kohm – 2 M ohm, then the output is connected to G2 in the RGB channels.
If still can not mean Flyback be grafted / dicascade / in double flybacknya.

B + II high to low voltage using a FET IRF 9610.
FET uses a 9 V to Vcc zener her. Input voltage of 125 V PS was lowered to 80 V.

Goldstar 14 dead PS
Check the Vcc Tr STR trigger for PS. Vcc is obtained from the AC voltage drop across R 220 is passed two 22K ohm in series, which is then feed them to the base of Tr Trigger.

Samsung 15 if the switch is off screen nitik FBT if the light in the middle
There is a path that is not connected to the FBT line of about 200V TR RGB amplifier that originally got the voltage of the FBT. Make a solution of the same voltage.

SPC 14 horizontal lines in the middle
Check the Vcc voltage of 21 V Vertical passed PS R 1 ohm fuse on pin 3 Vertical IC TDA 1175. when Vcc is missing, the IC is damaged, replace it.

AOC 14 bottom screen scroll to the top
Check the Vertical IC connections, cracks often occur. CRT Monitor Service Guide

 

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source: ekohasan blogspot.

CRT Monitor Service Guide | twinqu | 4.5