The model is sharp 29L-FG1A,the problem is a green screen with while retrace lines.where to start checking?the RGB ampliflier stage?

removing flyback lines by adjusting the FBT "Screen" trimmer measuring 4000 to 5000 DCV from G2 at CRT socket pin. Check RGB transistors in CRT board circuit to remove green screen.

check the G2 ,if to high retrace lines wil be vissable.If ok check the RGB,12V on picturetube panel.
Are the lines in one collor then check the circuit of theat collor

This fault is due to leakage of electrolytic capacitors in the vertical stage that is why top retrace lines are visible over the picture,if you are technical person check the capacitors in the vertical stage by replacing the same.

Hello
It seem to be due to the fault of video output stage. You just measure the voltages at the red,green, and blue cathodes at the CRT base. It should be less than the video output supply voltage, something 50 or 60VDC lesser than that voltage. First check the video output supply voltage. It will come around 270 or so. If there is no difference between the video supply voltage, and the voltage at the cathodes, means that the video output Ic or transistor, whichever may be, don't gets proper RGB signal voltages from the main board. You just increase the focus voltage and ensure that proper voltage is there or not. It can be assured by turning the focus control. Normally there will be two focus controls for large screen TVs, both for horizontal and vertical planes, just turn the horizontal focus control only.
You haven't mentioned about tthe system display condition. If video amp stage has any trouble, menu display will also be improper. Just check these and if you need any more help, please inform me through Fixya. OK.

Dear sir/Madam,

Check power supply(SMPS) section.Check/replace all electrolytic capacitor without power capacitor and resoldaring power supply section after then check horizontal output transistor.


thanking you
uttam
[email protected]

Oh dear ! I fear my answer may not be what you want hear but my advise is free. Bright green raster with Flyback (retrace) lines may indicate a heater cathode short in the tube (crt) this causes a sharp increase in beam current and the power supply shuts down into standby mode. To prove the point isolate the red and green cathode pins on the tube base and cross couple the red video output stage to the green cathode pin and the green output to red cathode pin using wire links. If set now comes on with bright red raster the fault is in the green video output stage and not the tube. If still bright green then tube is most likely cause. Gently tapping the tube neck may prove the point, but take care the tube neck is thin glass and if hit too hard will break compounding your problems. WARNING if you do not feel totaly confident to attempt this level of repair there is no shame in seeking the advice of your local service technician. Safety first always

This is what we called RETRACE LINE. This happens when the 200 V at C board is missing. Some times a 4.7 Ohms fusible resistor open, and find out the reason why it opens, could be a damaged RGB drive. The worse if retrace line show up together with a saturated green picture your green gun is damaged, in this case you have to change your CRT. Good Luck

Normal 0 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} 1. Turn the green screen control on the Focus Block until retrace lines appear and gradually turn it back
Until the point where you can see the retrace line disappears, just before cutoff.
2. Turn the red screen control on the Focus Block until retrace lines appear and gradually turn it back
Until the point where you can see the retrace line disappears, just before cutoff.
3. Turn the blue screen control on the Focus Block until retrace lines appear and gradually turn it back
until the point where you can see the retrace line disappears, just before cutoff.
4. If the screen still appears too bright after proper G-2 adjustment, you need to adjust the sub-bright adjustment in the service menu
control down until screen cut-off. (Service data Range is usually 21 to 25 in the Service menu, for Sony sets you first go to category "MCP2", & then adjustment item 01( "SBRT")= subright.
For electrical the focus, put on the screen a clear picture of your choice thru an input of the TV set from a DVD, then pause the playback of the DVD Look into each color and rock that color focus control back and forth (turn the control one way then the other way slowing down as the picture goes into the best focus. till the picture looks sharp do each color till they all look in focus. NOTE: it is best to look into each color tube to achieve the best electrical focus. For optical focus please follow the manual lens adjustment in the sets service manual
By Larry Dillon

TV FINE UNTIL 2 NIGHTS AGO HAVE HAD 4 YEARS, STARTED HAVING A FOGGY SCREEN WITH WHITE HORIZONTAL LINES. HAS SOUND A FOGGY SCREEN WITH WHITE HORIZONTAL LINES. called retrace lines please check 1 screen control on eht transformer is mituned 2 supply to screen of crt 3 supply to rgb video output is absent 4 connector loose 5 crt base loose thanks

could be but there are a few checks that need to be donr first.. Try to turn down the g2 control just a bit on the flyback transformer. If no effect unsoder the blure drive transistor on the crt board If the blue is still there that means the crt is shorted and you could try to clean the elements with a crt rejuvenator and see if that helps. If the screen goes to red and green after you disconnect the blue drive transistor then you need to check the osd drivers as well as the rgb output drive from the video IC. If the blue gun in the tube shorted or leaky I have in the past and it really works a isolation transformer that plugs in to the crt socket and the other end plugs into the crt. What this does is isolate the the gun of the crt from the filiments and thats where they get shorted or leaky but for how long it will last who knows.