What could cause a fully white screen, backlight on, no video?
general question, have seen this fault many times.

Bart Bervoets

Bart:
The problem would seem to located in the controller board.
Many of these are multi-layer boards. I have had some luck
with resoldering the whole board, even the solder-thru holes
where possible. Must have been an inter-layer break.

Some of the older LCD's used a lot of surface mounted
electrolytic capacitors, which were always going high ESR.
I could not get the manufacturer to sell me any of these boards.
Good luck..
John

wrote:
Bart:
The problem would seem to located in the controller board.
Many of these are multi-layer boards. I have had some luck
with resoldering the whole board, even the solder-thru holes
where possible. Must have been an inter-layer break.

Some of the older LCD's used a lot of surface mounted
electrolytic capacitors, which were always going high ESR.
I could not get the manufacturer to sell me any of these boards.
Good luck..
John


I have a flat panel monitor with a similar problem, and I shall take
your advice. Do you by any chance know what signals are going to the
display panel from the logic board via the cable on such monitors? I
put a scope on the leads and I can see data such as would be on the
cathode of a CRT monitor, and what appears to be a vertical signal. I
am curious as to how they control the horizontal and vertical scan of
the flat panel monitor. I would assume that several of the leads are
digital and select the horizontal position??

Ken

On Fri, 30 Jun 2006 12:07:56 GMT, Ken put finger
to keyboard and composed:

Do you by any chance know what signals are going to the
display panel from the logic board via the cable on such monitors? I
put a scope on the leads and I can see data such as would be on the
cathode of a CRT monitor, and what appears to be a vertical signal. I
am curious as to how they control the horizontal and vertical scan of
the flat panel monitor. I would assume that several of the leads are
digital and select the horizontal position??

Ken

AFAICT, all the signals are digital. I believe the interface standards
used in most panels are TMDS and LVDS.

This old post contains links to specs and tech notes:
http://groups.google.com/group/alt.c...e=source&hl=en

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

Franc Zabkar wrote:
On Fri, 30 Jun 2006 12:07:56 GMT, Ken put finger
to keyboard and composed:

Do you by any chance know what signals are going to the
display panel from the logic board via the cable on such monitors? I
put a scope on the leads and I can see data such as would be on the
cathode of a CRT monitor, and what appears to be a vertical signal. I
am curious as to how they control the horizontal and vertical scan of
the flat panel monitor. I would assume that several of the leads are
digital and select the horizontal position??

Ken

AFAICT, all the signals are digital. I believe the interface standards
used in most panels are TMDS and LVDS.

This old post contains links to specs and tech notes:
http://groups.google.com/group/alt.c...e=source&hl=en

- Franc Zabkar

Franc,

Thanks for the links, they will be very useful. I don't know if I will
solve my problem, but at least I have some idea of what is going on.

Ken

On Sat, 01 Jul 2006 12:09:39 GMT, Ken put finger
to keyboard and composed:

Franc Zabkar wrote:
On Fri, 30 Jun 2006 12:07:56 GMT, Ken put finger
to keyboard and composed:

Do you by any chance know what signals are going to the
display panel from the logic board via the cable on such monitors? I
put a scope on the leads and I can see data such as would be on the
cathode of a CRT monitor, and what appears to be a vertical signal. I
am curious as to how they control the horizontal and vertical scan of
the flat panel monitor. I would assume that several of the leads are
digital and select the horizontal position??

Ken

AFAICT, all the signals are digital. I believe the interface standards
used in most panels are TMDS and LVDS.

This old post contains links to specs and tech notes:
http://groups.google.com/group/alt.c...e=source&hl=en

- Franc Zabkar

Franc,

Thanks for the links, they will be very useful. I don't know if I will
solve my problem, but at least I have some idea of what is going on.

Ken

FWIW, there is a Samsung SyncMaster 770TFT service manual, with
circuit diagrams and setup procedures, at Datasheetarchive.com.

http://www.datasheetarchive.com/data...rticle=3725491

It may help you understand the general principles.

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