Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Default NEC LCD TV LNT-30CW no colour

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...)
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Default NEC LCD TV LNT-30CW no colour

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...)

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Default NEC LCD TV LNT-30CW no colour

On Wed, 11 Nov 2009 11:12:45 +0800, TonyS
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.
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Default NEC LCD TV LNT-30CW no colour

Franc Zabkar wrote:
On Wed, 11 Nov 2009 11:12:45 +0800, TonyS
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
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