NEC LCD TV LNT-30CW no colour

[TonyS]

I was given this defective LCD TV. It had no working backlight.
I located a faulty transformer, one of 8, and replaced it.
Backlight is working now.

However, the only way to get colour is when I use the component inputs.
I don't believe the 2 faults are connected, in fact I don't even know if the
colour problem could be fixed by setup. I got no service manual.

Has anyone out there an idea where I could start?

Cheers

Tony
PSI am running the unit on an temporary PSU.
The original PSU was missing (24V 6A) and the one I ordered on eBay (China)had
the 4 pins wrongly connected, believe it or not! Rotated by 90 deg. Lucky it
just shorted and didn't reverse the voltage...)

 

[TonyS]

TonyS wrote:

I was given this defective LCD TV. It had no working backlight.
I located a faulty transformer, one of 8, and replaced it.
Backlight is working now.

However, the only way to get colour is when I use the component inputs.
I don't believe the 2 faults are connected, in fact I don't even know if
the colour problem could be fixed by setup. I got no service manual.

Has anyone out there an idea where I could start?

Cheers

Tony

PSI am running the unit on an temporary PSU.
The original PSU was missing (24V 6A) and the one I ordered on eBay
(China)had the 4 pins wrongly connected, believe it or not! Rotated by
90 deg. Lucky it just shorted and didn't reverse the voltage...)

 

[Franc Zabkar]

On Wed, 11 Nov 2009 11:12:45 +0800, TonyS <scarborofun@gmail.nspm.com>
put finger to keyboard and composed:

I was given this defective LCD TV. It had no working backlight.
I located a faulty transformer, one of 8, and replaced it.
Backlight is working now.

However, the only way to get colour is when I use the component inputs.
I don't believe the 2 faults are connected, in fact I don't even know if the
colour problem could be fixed by setup. I got no service manual.

Has anyone out there an idea where I could start?

Have you checked the 4.43MHz crystal (or 8.86MHz)?

Have you tried feeding the TV an NTSC signal (from a region 1 DVD) via
the composite inputs?

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

 

[TonyS]

Franc Zabkar wrote:

On Wed, 11 Nov 2009 11:12:45 +0800, TonyS <scarborofun@gmail.nspm.com
put finger to keyboard and composed:


Have you checked the 4.43MHz crystal (or 8.86MHz)?

The thing has a big 144pin VSP9427B chip "Color Decoder and Scan-Rate Converter"
from Micronas which is clocked by a single 20.25 MHz crystal.

Have you tried feeding the TV an NTSC signal (from a region 1 DVD) via
the composite inputs?

don't have such a beast...

Thanks anyway.
It's not commercial, so I am using only the component inputs for now.

- Franc Zabkar

Tony