[Coco] Bad news, good news...

[jdaggett at gate.net]

Roger

Yes there are different means of demodualting the I and Q 
chromanance signal inside the TV. Two means come to mind and 
one is simpler and cheaper. The other far more difficult and more 
costlier. Consequently the low end TVs will opt out for the simpler 
means which yields color loss in the orange and cyan hues. 

You may try playing with the tint control. Tint and Hue are related. 
But lower cost systems actually reduce chromanance bandwidth 
enough that when you push the limits of the TV with the Coco 3,you 
get a poor display. Sometimes worse than that of the CM8 monitor.

Yes you are right that the RGB signals from the Coco are different 
from that of the PC.

james

On 10 Dec 2005 at 15:43, Roger Merchberger wrote:

Date sent:      	Sat, 10 Dec 2005 15:43:55 -0500
To:             	coco at maltedmedia.com
From:           	Roger Merchberger <zmerch at 30below.com>
Subject:        	[Coco] Bad news, good news...
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> After almost 4 years, I've finally sparked up one of my CoCos again!
> 
> Our local "Mega Mart" (if you can call it that) had 15" LCD TVs on
> sale for $188. The wifey wanted to pick up one of these critters as a
> "Bedroom TV." Roger was thinking "CoCo TV!" ;-)
> 
> Wifey came home with the TV last nite, so Roger had to try it out
> today. Roger goes up to the 3rd floor attic (a chore in and of
> itself!), grabs a CoCo3, comes down, plugs 'er in, nuthin but green
> screen. Ratz. Back to the attic, I grab a CoCo3 box, and yet I'm not
> smart enough to look inside whilst I'm up there. Get downstairs, open
> the box, CoCo2. Ungh. After cursing myself out for being a moron, I
> head back to the attic once again, and grab "my" CoCo3. The one I
> bought new lo, those many years ago. Trudge 'er back downstairs, spark
> 'er up, and Bam! Alive it is! And looks kinda crappy. :-( 40 Columns
> didn't get any better[1] and 80 columns was... well... pretty much
> unreadable, no matter how you slice it.
> 
> I'm not sure if it's the RF modulator in the CoCo, the RF demodulator
> in the TV (It's not exactly a Sony after all) or both working in
> concert to make me unhappy... tho I did start wondering a few things:
> 
> a) if I could pick off the Chroma & Luma & feed it into the SVGA
> port... would that improve the video at all?
> 
> b) if the video circuitry on the VGA port will sync down to NTSC
> levels. IIRC, tho, the voltage requirements of the RGB port on the
> CoCo and standard VGA aren't quite the same. If I'd "underdrive" the
> VGA circuit, I'd solder up a cable & try 'er, but if I "overdrove" the
> VGA... well... I doubt my wife would be happy if I let the magic smoke
> out of what's basically her TV having owned it less than 24 hours.
> 
> There is good news, tho: [2] I popped the lid on the first CoCo3,
> reseated the memory chips, and everything came to life.
> 
> Oh well, can't say I didn't try. Maybe if the wife gets out of doing
> daycare, I'll finally have room to set up my CoCo full time again
> soon...
> 
> Laterz,
> Roger "Merch" Merchberger
> 
> [1] (well, after I diddled with ATTR & CLS# I got it readable, but it
> wouldn't win any beauty contests...)
> 
> [2] Y'all prolly thought this was a segway to a Geico commercial...
> ;-)
> 
> --
> Roger "Merch" Merchberger   | "Bugs of a feather flock together."
> sysadmin, Iceberg Computers |           Russell Nelson
> zmerch at 30below.com          |
> 
> 
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