[H-GEN] Monitor conversion - GB to RGB

[z_evil1]

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Greetings, all...

> One of my screens at home has lost its red colour.
> 
> I'm interested in hearing from anybody who thinks s/he knows a
> cheap and easy fix for this.

 Disclaimer: I am not a monitor tech, although I have a mate who is. That
said, I've solved a few problems like this before...

 The likely causes are, in order of probability: loose cable, bent red
pin, damaged cable, dry joint on neck board on driver transistor, other
red driver circuitry problem, dead red gun in tube, dead red circuitry on
video card (I've never seen this last, BTW.)

 The first three you can check yourself. (For number 2 - wiggle the cable
while watching the screen. If a chairleg has not sat on it, one end or the
other will contain the dodgy part. A small mirror and a colour-rich image
may help here.)  The fourth will require a mate with a soldering iron and
a bit of caution to fix - but quite often these days, I've found,
especially with cheaper monitors (ProView, anyone?) the three driver
transistors on the neckboard run hot enough to gradually dry their solder
joints, leading to sometimes intermittent loss of colour(s). The solution
here: unsolder the neck board shield, resolder all three transistors, and
replace the shield. Disclaimer 2: monitors and TVs both contain extremely
dangerous voltages and components. Only people who know what the dangerous
parts of a monitor are and know how to avoid them/treat them with with
respect should attempt such a repair. You CAN be killed by touching the
wrong part of a monitor...

 The fifth is somewhat more complex, but most of the circuitry on the
neckboard is in triplicate - one for each colour. You could swap parts
between colours until the fault shifts too, but this is getting a little
involved and in the realm of "professional" help.

 The sixth means - buy a new CRT. :) If you are nice to the fixit man,
they might have a go at "rejuvenating" your tube, which verrrry
occasionally fixes problems like this, but usually, give up and get a new
monitor. I have to say, though, actual individual gun failures are pretty
rare...

 Hope that helps. And if you don't know what EHT or the CRT capacitance
is, don't even think about opening the back cover. :)

 Regards, Vince


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