Why does it look so crap?

April 27, 2006 12:59 AM

Why does my the second monitor attached to my 20" iMac duocore produce such lousy colour?

The output on my second monitor, attached to 20" iMac Intel DuoCore via Apple's own min-DVI-to-SVGA adapter, looks like hell.
I've attached a Dell P991 19" Trinitron monitor from my previous Wintel setup (where the Matrox G350 card produced excellent image quality) to my iMac's external miniDVI output.
Unfortunately there's a sick jaundiced cast to the monitor's output. I tried every control on the monitor, and played extensively with the colour temp settings -- no luck.
OSX 10.4 is accurately "seeing" the monitor: it identifies it by model and make...but the output is terrible.
Is this something I can change via the OS, or is it endemic to miniDVI-to-SVGA connections?
I'd really love to have that extra desktop space, so any help would be appreciated...

posted by I, Credulous to Computers & Internet (8 answers total)

Those DVI to SVGA adapters are sometimes very very picky.

If you have a friend with one, try his.
posted by k8t at 1:27 AM on April 27, 2006

Have you tried the monitor on another computer since you've started having this problem with the iMac, or are you just remembering its performance from previously?

I ask because 'sick jaundiced cast' sounds a lot like broken monitor to me.
posted by chrismear at 4:55 AM on April 27, 2006

Or loose cable, possibly.
posted by chrismear at 4:56 AM on April 27, 2006

Third the loose cable/bad connection.
posted by qwip at 5:41 AM on April 27, 2006

The VGA connector carries red, green, and blue signals on separate pins. One time I had a monitor that had a disgusting "jaundiced" look to it. I unplugged the monitor and looked at the VGA cable. When I did, I noticed a pin inside the connector that had somehow gotten bent down. Turns out it was the blue pin, which explained why everything was red, green, and yellow. 30 seconds and a pair of needle nosed pliers and my monitor was back in all of its full-color glory.
posted by cebailey at 6:13 AM on April 27, 2006

Response by poster: chrismear & cebailey: I had to go back to the old machine to recover some data, and thus re-attached the Trinitron to the old machine. It looked as good as ever. That would likely rule out bent pins and dying monitor, but I will look more closely at the cable.
A loose connection does seem like a real possibility, though, as that miniDVI connector isn't large, and the cable can weigh heavily on that small bit of connector. I'll try re-attaching it and "wigglin'" it to see if the connection improves.

thanks all for your tips...i'll report back what if anything fixes it.
posted by I, Credulous at 6:56 AM on April 27, 2006

the cable can weigh heavily on that small bit of connector

That would make sense. The mini-DVI port on the iMac is mounted sideways, with the R, G and B pins running vertically. I can't tell from Apple's docs whether R or B is at the top, but if it's B then pulling down on the cord would affect the blue signal first, giving you your yellow-tinted screen.
posted by chrismear at 11:11 AM on April 27, 2006

Response by poster: Well, I checked the connection, and it seemed as tight as it ever did. To help, though, I routed the second monitor's cable through the hole in the iMac's stand, so it's not dangling right from the point of connection.
I restored the monitor's display settings to something approaching neutral, then using the colour calibration tool I tweaked every setting to improve it as much as I could. Then went back to the monitor's manual controls and further tweaked it all.
The result is better colour registration, though overall it looks dull compared to the built-in display (I'm just going to chalk that up to LCDs being brighter overall...and then smile some because the built-in display looks so damned good!)

So, that's it: no real magic. No real "A-ha!" solution. Just a fair amount of tweaking on both the iMac and the monitor...
oh, and potentially avoiding problems down the road by supporting the monitor cable at the miniDVI connector.

peace,

out,

I, C
posted by I, Credulous at 9:08 PM on April 27, 2006