Wayne Peacock wrote in
:

Hi all,

I have a sun GDM-5010PT 21' monitor that I have just fixed the power
supply for. Now the brightness is very dim and I need to up the screen
or sub-brightness. And yes the power supply rails all test OK.

I am aware there are no trimpots and most settings are controlled by
software (DAS from what has been listed in this group). How can I
increase the brightness without the software or would someone have the
protocol for the serial connection?

I am very capable of writing a program and wiring a cable for this if I
know what to write to the monitor. Can a resistor be changed etc?

What is the normal life of a trinitron tube? This monitor was made in
march 1998 and has likely been on for it's life. Could it be on it's
last legs

If it's anything like some Sony TVs, you might want to check the value of
the resistors on the tube base before consigning the whole thing to the
scrapheap. Do cold checks on anything above 100K to see if the values have
drifted - I've had plenty that do, causing picture effects not dis-similar
to tube wear. Of course, this doesn't negate the other useful responses
you've had thus far.