Futura (Viewmate, Likom) LDF770 -- where's the screen contro

[Joe]

I'm knee-deep in CRT parts trying to adjust the brightness on my
Futura 17" ldf770...I crack the puppy open only to find out that
there's two focus controls and zero brightness, screen, or master
screen controls.

I'm figuring I'm just stupid and can't find it -- I'm not overly eager
to go popping any other shielding open unless I know that the control
is in there somewhere.

I can confirm that it's not readily visible on the Flyback/LOPT
transformer (where I've located the dual focus knobs). I can also
confirm that it's not visible on the board on top of the CRT -- there
are several possible adjustments, but all seem to have to do with
bowing, or horizontal/vertical length.

I also can't locate it on the main video board, although granted that
I'm not exactly sure what I'm looking for.

Can anyone help me out?

 

[Joe]

I have confirmed that there is no such analog control located within
the monitor. I know I haven't recieved any replies, but maybe some
sucker in the same situation I am will need to know to stop looking.


I've been told that adjustment of the factory presets would help, but
I don't know how to.

 

[Andre]

avatarolt@cox.net (Joe) wrote in message news:<b9944a39.0401271454.71bae3ea@posting.google.com>...

I have confirmed that there is no such analog control located within
the monitor. I know I haven't recieved any replies, but maybe some
sucker in the same situation I am will need to know to stop looking.


I've been told that adjustment of the factory presets would help, but
I don't know how to.

It might be stored in EPROM; most newer monitors are of this type with
push button controls. This also means that if the EPROM gets corrupted
you will see very strange results (possibly a "washed out" picture or
even blank)

-A

 

[John Gill]

Joe:
Some monitors use a DAS (Digital Alignment System - Expensive) to adjust
the screen voltages. I believe that Futura is a cheap brand and I would
not expect them to use a DAS.
Have you tried taking the shield off of the CRT neck board and then
follow the G2 (screen) circuit douwn into the main board ?
Some sets (Gateway, for example) use a fixed resistor to set the G2
voltage and you have to change the resistor to adjust the screen
voltage. The G2 pin is the 3rd pin going clockwise after the Focus
pins.
Hope this helps...
John