Mitsubishi Diamond Plus 200 insufficient blue

[[email protected]]

I just got an old 22" Mitsubishi Diamond Plus 200 CRT monitor.
The previous owner said that the picture was "greenish".
He didn't say anything else about it.

The problem is that the blue color is about one tenth as bright as it
sould be, which means the colors look greenish-browning, unless I set
the red and green gains down to where I can barely see the image in a
normally lit room.

Of course, I tried to set the blue gain to the max setting, but it is
still one tenth as bright as it should be, by my estimation.

I opened the unit up and looked inside. It is fairly free of dust.
The parts of it that I could see without taking it completely apart
didn't show any visible defects such as burned parts, loose connectors,
broken wires, scorch marks, et cetera.

Aside from the dim blues, the unit works just fine, and I would like to
take a shot at fixing it.

Does anyone have any suggestions for what I should check first, second,
third, and so on?

Thanks to all of you.

Graviton.

 

[Sjouke Burry]

I just got an old 22" Mitsubishi Diamond Plus 200 CRT monitor.
The previous owner said that the picture was "greenish".
He didn't say anything else about it.

The problem is that the blue color is about one tenth as bright as it
sould be, which means the colors look greenish-browning, unless I set
the red and green gains down to where I can barely see the image in a
normally lit room.

Of course, I tried to set the blue gain to the max setting, but it is
still one tenth as bright as it should be, by my estimation.

I opened the unit up and looked inside. It is fairly free of dust.
The parts of it that I could see without taking it completely apart
didn't show any visible defects such as burned parts, loose connectors,
broken wires, scorch marks, et cetera.

Aside from the dim blues, the unit works just fine, and I would like to
take a shot at fixing it.

Does anyone have any suggestions for what I should check first, second,
third, and so on?

Thanks to all of you.

Graviton.

One thing which sometimes helps, reflow all connections on the board
plugged onto the tube.

 

[N_Cook]

I just got an old 22" Mitsubishi Diamond Plus 200 CRT monitor.
The previous owner said that the picture was "greenish".
He didn't say anything else about it.

The problem is that the blue color is about one tenth as bright as it
sould be, which means the colors look greenish-browning, unless I set
the red and green gains down to where I can barely see the image in a
normally lit room.

Of course, I tried to set the blue gain to the max setting, but it is
still one tenth as bright as it should be, by my estimation.

I opened the unit up and looked inside. It is fairly free of dust.
The parts of it that I could see without taking it completely apart
didn't show any visible defects such as burned parts, loose connectors,
broken wires, scorch marks, et cetera.

Aside from the dim blues, the unit works just fine, and I would like to
take a shot at fixing it.

Does anyone have any suggestions for what I should check first, second,
third, and so on?

Thanks to all of you.

Graviton.

Try swapping red and blue drive lines. Isolates to the final or earlier
stages

 

[[email protected]]

Try swapping red and blue drive lines. Isolates to the final or earlier
stages

I'm not a professional, just an experience amateur, so my tools and
skills are limited. Could you provide more details on this procedure?

Thnx.

 

[[email protected]]

edited


I'm not a professional, just an experience amateur, so my tools and
skills are limited. Could you provide more details on this procedure?

Thnx.

Also, could someone point me in the direction of a pdf of the service
manual that I could download? Preferably for free?

Thnx.

 

[[email protected]]

Also, could someone point me in the direction of a pdf of the service
manual that I could download? Preferably for free?

Thnx.

Additional symptom: when it starts up, the blue comes on from the bottom
of the screen up, but in less than a second.

Thnx.

 

[[email protected]]

Well, I'd start with centering the blue control, maybe the red and
green
too, then readjust the high voltage "screen" or "G2". You need a
grey-bars
test signal to readjust the color (first diddle the RGB offsets, to
get
the darkest bar neutral gray, then change the RGB gains to make
the lightest bar neutral).

Some monitors do a lot of this through software, but removing the case
back and poking in with small adjustment screwdrivers is the usual
procedure. Beware the high voltage (anode) wire; your adjustments
have to be made with power ON.

I don't see any hardware RGB adjusters. I've only used the software
controls.

 

[Sitre Josephenne Magana]

I just got an old 22" Mitsubishi Diamond Plus 200 CRT monitor.
The previous owner said that the picture was "greenish".
He didn't say anything else about it.

The problem is that the blue color is about one tenth as bright as it
sould be, which means the colors look greenish-browning, unless I set
the red and green gains down to where I can barely see the image in a
normally lit room.

Of course, I tried to set the blue gain to the max setting, but it is
still one tenth as bright as it should be, by my estimation.

I opened the unit up and looked inside. It is fairly free of dust.
The parts of it that I could see without taking it completely apart
didn't show any visible defects such as burned parts, loose connectors,
broken wires, scorch marks, et cetera.

Aside from the dim blues, the unit works just fine, and I would like to
take a shot at fixing it.

Does anyone have any suggestions for what I should check first, second,
third, and so on?

Thanks to all of you.

Graviton.

It means that the software driver for the blue electron gun needs to be
updated.