I'm repairing (in theory) a 3 year old monitor, ie far more recent than my
own, so unfamiliar territory.
It uses an NT6827 on screen data display generator and LM1269NA CRT
controller.
The NT6827 is loading the 5V rail and tripping the protection circuitry.
Should be maximum of 25mA at 5V but putting a dropper in line it is taking
70mA when dropped to 3V.
If I disconnected this IC would the monitor work at a basic level or default
to zero brightness etc?

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

N Cook wrote:
I'm repairing (in theory) a 3 year old monitor, ie far more recent than my
own, so unfamiliar territory.
It uses an NT6827 on screen data display generator and LM1269NA CRT
controller.
The NT6827 is loading the 5V rail and tripping the protection circuitry.
Should be maximum of 25mA at 5V but putting a dropper in line it is taking
70mA when dropped to 3V.
If I disconnected this IC would the monitor work at a basic level or default
to zero brightness etc?



Try it and find out, have you checked on the price of a new IC though?

"N Cook" wrote in message
...
I'm repairing (in theory) a 3 year old monitor, ie far more recent than my
own, so unfamiliar territory.
It uses an NT6827 on screen data display generator and LM1269NA CRT
controller.
The NT6827 is loading the 5V rail and tripping the protection circuitry.
Should be maximum of 25mA at 5V but putting a dropper in line it is taking
70mA when dropped to 3V.
If I disconnected this IC would the monitor work at a basic level or
default
to zero brightness etc?


If the IC really is purely an on screen data display generator then I can't
see how disabling/removing it would affect anything other than the monitors
ability to display the OSD graphics. Why not try and and see?

Dave

"Dave D" wrote in message
...

"N Cook" wrote in message
...
I'm repairing (in theory) a 3 year old monitor, ie far more recent than
my
own, so unfamiliar territory.
It uses an NT6827 on screen data display generator and LM1269NA CRT
controller.
The NT6827 is loading the 5V rail and tripping the protection circuitry.
Should be maximum of 25mA at 5V but putting a dropper in line it is
taking
70mA when dropped to 3V.
If I disconnected this IC would the monitor work at a basic level or
default
to zero brightness etc?


If the IC really is purely an on screen data display generator then I
can't
see how disabling/removing it would affect anything other than the
monitors
ability to display the OSD graphics. Why not try and and see?

Dave



I cut the 5V line to the OSD and the monitor stayed powered with all ps
rails ok and HT crackle at switch off but zilch on screen feeding from a PC.
New ICs not available apparently in UK and otherwise 100 minimum or 250 USD
min of course.
I'll download the OSD IC datasheet and see if I have to take the R,G,B lines
high or something.

"Dave D" wrote in message
...

"N Cook" wrote in message
...
I'm repairing (in theory) a 3 year old monitor, ie far more recent than
my
own, so unfamiliar territory.
It uses an NT6827 on screen data display generator and LM1269NA CRT
controller.
The NT6827 is loading the 5V rail and tripping the protection circuitry.
Should be maximum of 25mA at 5V but putting a dropper in line it is
taking
70mA when dropped to 3V.
If I disconnected this IC would the monitor work at a basic level or
default
to zero brightness etc?


If the IC really is purely an on screen data display generator then I
can't
see how disabling/removing it would affect anything other than the
monitors
ability to display the OSD graphics. Why not try and and see?

Dave



The control pin on the LM1269 when low from the NT6827 should be video not
OSD should
be ok. According to user manual should be able to count/step through the OSD
menu unseen.
But now no sustained HT , well G2 volts at least - ho hum