Mitsubishi Diamond Plus 220 monitor - insufficient brightness

[Luke Siemaszko]

Supericially this montior works OK. But when doing colour critical work
the colours are wrong, so I start to set it up from scratch

Start with the brightness
As far as I am concerned the Right Way to set brightness is to display a
blank raster, turn up the brightness until the raster is just visible,
then back it off a little.

- but I can never get a visible raster.
There are two possible causes
Vg2 too low
Wrong black level in video amplifiers

But I can't set these withot a service manual 'cos I don't know what the
Vg2 is supposed to be


Does anyone have a service manual for this model?
Spec for Vg2?
Details of where the adjustments for Vg2 and video black level are?

Thanks very much

 

[James Sweet]

Supericially this montior works OK. But when doing colour critical work
the colours are wrong, so I start to set it up from scratch

Start with the brightness
As far as I am concerned the Right Way to set brightness is to display a
blank raster, turn up the brightness until the raster is just visible,
then back it off a little.

- but I can never get a visible raster.
There are two possible causes
Vg2 too low
Wrong black level in video amplifiers

But I can't set these withot a service manual 'cos I don't know what the
Vg2 is supposed to be


Does anyone have a service manual for this model?
Spec for Vg2?
Details of where the adjustments for Vg2 and video black level are?

Thanks very much

Is there a sub brightness/screen control on or near the flyback? If so
you could bump it up a bit. It's quite possible that the CRT is simply
aging.

 

[Luke Siemaszko]

Is there a sub brightness/screen control on or near the flyback? If so
you could bump it up a bit. It's quite possible that the CRT is simply
aging.

I'm being a coward - I don't have the time to experiment, I am hoping to
get the correct service information to make sure I get it right. I'm
not keen to just turn something up, because the Vg2 *has* to be right
according to the designer's calculations.