Curiosity: Darker to lighter strip 1/3 from left side of some TVs.

[Jason D.]

While displaying dark pictures or faint dark images.

The TVs with this characteristic is working and CRT is not the
problem; purity is excellent and even phosphors.

For example:

AV-20020 shows this, while AV-27890 do not both are JVC and based on
similar horizontal circuits except AV-27890 have active pincushion
correction.

What this is caused by?

Cheers, Wizard

 

[JANA]

If you are referring to the shading characteristics of the CRT when the
there is a dark grey screen, this has to do with the accuracy of the
clamping and blanking circuits. The accuracy of the horizontal blanking
circuit can cause this.

Many consumer TV sets have all types of small errors. This is why they cost
much less than professional TV monitors.

--

JANA
_____


While displaying dark pictures or faint dark images.

The TVs with this characteristic is working and CRT is not the
problem; purity is excellent and even phosphors.

For example:

AV-20020 shows this, while AV-27890 do not both are JVC and based on
similar horizontal circuits except AV-27890 have active pincushion
correction.

What this is caused by?

Cheers, Wizard

 

[Mark]

digital or anlog TV?

If analog, you could be seeing a ghost of the horizontal sync pulse
which of off to the left of the screen. If there is a ghost
(reflection) you will see this on the screen as a vertical bar.

Mark