horizontal white lines covering all of the TV screen

[AliTonto]

I have this tv that has parallel horizontal white lines that cover the
whole screen; they are spaced apart for most of the screen but get
closer together up the top. I have replaced electrolytics in vertical
section but no change.
Whatelse could be causing this problem?
Any info will be helpful.
Thank you.

 

[john]

Try the scan circuits...If we had the Make and Model
we could be more helpful.

kip

 

[Matt J. McCullar]

Sounds like what you're seeing are "retrace lines," which means the raster
could be turned up too high. See if adjusting the SCREEN control on or near
the flyback helps a little. In effect, you're turning down the master
brightness.

 

[Jim Lazzaro]

I beleive the vertical chip could be faulty.Have you checked Vcc?
Jim

 

[AliTonto]

Hi John
The is part of an alarm clock radio Superstar Model and the board
description is PB1001-H(Rev.3)
I can identify the vertical chip AN5151N. If this is a possible
suspect, could anyone give me the pinouts please.
Thank you.
AT

 

[BWL]

Low 200v to the CRT will cause this as well; could be an open or changed value
resistor in the 200 volt circuit, usually powered by a winding/diode/filter cap
off the flyback transformer.

 

[Mr TUBEAMPS]

thay are retrace lines, nothing to do with
the vetical chip.

 

[General Specific]

I had similar symptoms with my TV. Turned out to be a cold solder on a diode
that was part of the power circuit. It used to display this screen just
before it cut out.

 

[AliTonto]

Yes, I think investigating the crt PCB further sounds hopefull; I will
check and return my results.
Thanks to all.

 

[AliTonto]

I have checked voltage to crt and it is at 262v.(I don't have specs)
I have replaced the diode feeding this which measured rather leaky.
I have now a better picture which looks normal at the top 1/5 of the
screen and from there dounwards the picture streches out more and more
into thin white horizontal lines.
Any further advice on what the problem could be? I will be happy to
solve this and maybe someone has the answer.
Thanking You.

 

[AliTonto]

I have checked voltage to crt and it is at 262v.(I don't have specs)
I have replaced the diode feeding this which measured rather leaky.
I have now a better picture which looks normal at the top 1/5 of the
screen and from there dounwards the picture streches out more and more
into thin white horizontal lines.
Any further advice on what the problem could be? I will be happy to
solve this and maybe someone has the answer.
Thanking You.

 

[BWL]

If by normal you mean the top 1/5 of the screen has a normal looking picture,
which then gets stretched further and further open as the image travels down
the screen, then your problem now is in the vertical circuit; probably a bad
capacitor, low voltage to the IC, or bad IC...