Samsung CRT TV letters or text is shadowing

[JohnNovak]

Hi.
I have some problem with old CRT TV Samsung model: CW-29Z338T, 29" size TV.
The problem is that letters and other text are not clear, text or letters are shadowed on the right side.

I found 2 capacitors on CRT Picture Tube Board.

47uF/400V was leaking very bad, the second cap 10uF/250V was bad ESR reading so i replace this cap also.

Replacement these 2 capacitors did not help nothing.

I try to reduce brightness, contrast and sharpness. There is very small effect on this shadow.

To reduce G2 down have more effect but then picture is too dark no matter i can reduce brightness with remote.

Any solution for this problem?

Picture 1 is program Travel after the show was over.
Picture 3 is menu from external Combo SAT receiver.

[R_J]

try replacing C402

[JohnNovak]

Hi R^J.

I replace C402 and C404 both 470uF.
I also check both old caps are ok.

[JohnNovak]

It is interesting that when the TV is cold, there is some disturbance in the picture, which then disappears slowly. The shadow is still present.

[R_J]

I made a mistake on the cap, it should have been C422, NOT C402. C422 is a 47µf 250v cap on the 200v supply from the flyback.

Is this the S63b chassis?

[JohnNovak]

Yes the cassis is S63B.
I also suspect this cap but have no any in stock.
I need to order it and wait to come.

[R_J]

If you have another 10µf/250v you could just bridge the 47µf and see if it helps

[JohnNovak]

I replace C422 with new and does not help anything.
Old capacitor show good condition.

[R_J]

Check the voltages on the crt neck board to see if they are correct.

[JohnNovak]

Voltages seems to be correct.

[JohnNovak]

I also found one bad capacitor in vertical section, cap C307=100uF/50V was high ESR and capacity 88uF.
I replace all 3 caps, C418, C302 and C307.

[JohnNovak]

Picture is a little better, white shadows still constantly present.
When TV is cold i have some lines in the picture which appears and disappears in about 3 seconds interval and rotate from horizontal to vertical position and back to horizontal.
Line disturbance take about 10 minutes to rotate for 180 degree, it is rotate very slowly.
After 5 to 10 minutes when TV is warming up this lines are almost invisible.

[JohnNovak]

I check voltages from SLA1004, HC801
and i found 12V = 11.27V
It is a little low and also feeds crt neck.
Can this be the problem?

[JohnNovak]

Problem solved with feature box repair.
SMD caps replacement.

[R_J]

Problem solved with feature box repair.
SMD caps replacement.

So the problem was with the input source (feature box), NOT the tv?

[stj]

i bet that box deals with multiplexing the signal with the OSD stuff.

[JohnNovak]

Feature box have very important function, have control on input signals from scart source and others. Also control deflection and other functions. For repair FB need to be removed from TV and make good caps checking and replacement. I replace 30 smd caps, most of them was very bad and high ESR readings.

There was some capacitors bad also on tube board and near vertical IC. But this have nothing with picture fault i have before.

[JohnNovak]

Feature box is part on TV it is pcb board and is not outside component.

[R_J]

ok, I had another look at the service manual and I see the feature box, I could see bad capacitors effecting the video quality

[JohnNovak]

This repair was quite demanding and took several hours. Carefully desoldering a PCB board with so many pins. And then replacing about 30 smd capacitors. But picture is ok now, clear of smearing.