CRT Colour Calibration

For monitor related issues
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dj_johnnyg
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CRT Colour Calibration

Post by dj_johnnyg »

Hi,
So I fired up my Mushiking cab with the original 14" CRT and was greeted to a very weird picture & I assumed a **** monitor.
Anyway, long story short Naomi set to 31k :palm: and the awesome </sarcasm> VGA connector that comes with the mushi cab being able to be plugged in upside-down actually plugged in correctly.

So I now have a nice-ish picture, albeit no red.

Fired up the Naomi test screen and indeed the red was gone. A little fiddle with the pots on the monitor and the red came back, but I'm still not happy. The white level is too blue/green for my liking, but when I drop these it gets very red very quickly.

Is there a recommended method to calibrate the colour on a CRT, or am I looking at a more serious issue? Hopefully plugging the VGA connector upside down hasn't trashed something.

Thanks

John
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Asayuki
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Re: CRT Colour Calibration

Post by Asayuki »

It sounds like your pots are dirty and need cleaning or replacement.
My 15kHz cabinet Peplos will never power up, with any item, and I am quite proud of that.
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dj_johnnyg
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Re: CRT Colour Calibration

Post by dj_johnnyg »

I've just found the Calibration page on the wiki :awe:

I think the Red pot is duff, as the blue & green seem to have a nice range from dark to bright, but the red seems to do nothing then over-saturated.

I've noticed the 3 pots on the neck-board for RGB. Is it worth doing anything here, or am I going to totally stuff something?

The wiki-page isn't particularly clear (for me anyway). I have R,G,B and brightness pots on the front panel, then the R,G,B on the neckboard.

I'm assuming the R,G,B on the front are the gain, with the neckboard being the cutoffs. I can't find a contrast or "screen" pot as mentioned in the wiki.

I'm going to pull both monitors out of the cabs and then I have full access to the whole unit. I'll see if I can get some readings from the pots as well while they're out & replace.
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cools
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Re: CRT Colour Calibration

Post by cools »

You can't stuff anything up ;)
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dj_johnnyg
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Re: CRT Colour Calibration

Post by dj_johnnyg »

cools wrote:You can't stuff anything up ;)
Challenge accepted.

Managed to swap out the monitor from the other cab so have 1 unit running nicely. Will take a look at the other when I have more time.
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dj_johnnyg
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Re: CRT Colour Calibration

Post by dj_johnnyg »

Bank holiday today, so time to fiddle (snigger)

Set about the chassis today with my multimeter and took some readings on the pots - all 5k. I was hoping for a remote board with the adjusting knobs so I could swap between monitors, but no such luck.

Anyway, the troublesome Red pot was functioning as expected, so I took a look at the ones on the neckboard, and again all fine.
I removed & reattached every cable that I could (i.e. any not carrying a voltage that could make me **** my pants) and swapped into my working Mushi cab. Colour still ****, but a small bit of tweaking & she's there.

Wish I knew what the real problem & fix were - could be all the fiddling with the knobs cleaned out all the mess (which is opposite to what usually happens when i fiddle with my knobs ;) ) or the cabling in the other cab is totally fubar'd - but it's getting a full re-wire as part of the project.
Snakes: They're like bits of rope, only angrier.
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