[Coco] CM-8 Monitor question

[Gene Heskett]

On Sunday 16 November 2014 11:15:49 Bill Pierce via Coco did opine
And Gene did reply:
> I have a CM-8 with a really sharp, clear picture with no "waves", lines
> or "sparklies", but it has one little thing that bugs me. The top
> right hand corner of the screen, starting from about half up, slowly
> angles slightly inward about 3/16ths of an inch at the top. The other
> 3 corners are perfect. Other than that, I couldn't ask for a better
> picture, though I often wonder "for how much longer?", as this monitor
> was bought the first year they came out.
> 
> 
> Is there any adjustment that can correct the dip in the picture?
> 
That would likely be a dried out, lost capacity from old age etc 
electrolytic capacitor in the power supply area.  The vertical retrace 
takes a good sized bit of current since its done in 3% of the time it 
takes to trace from top to bottom,  That sucks the voltage down and would 
tend to affect the width at the top of the screen.

I do not now recall if the CM8 had a speaker but if it does, and its on 
that side of the cabinet, there could be some small magnetic effect from 
its leakage field also that would slightly displace the corner/edge of the 
pix on that side.  That effect would be continuous and pixel stable.

So if it has a slow breathing motion to the distortion that may take 20 
seconds to a minute to notice because the coco's vertical synch isn't 
locked to the powerline, then I'd point fingers at the capacitors with any 
hesitancy.

Frankly, I am amazed that any cm8 is still working at this late date as 
all of my ntsc capable monitors have long since let the magic smoke out of 
the H.O.Transformer, and no replacements from North American Phillips have 
been available for any of those regardless of the brand name label on the 
front face trim, for 20+ years.

What we really need is to find a suitable 13 to 17" led illuminated 
monitor that Roy's and similar adapters can drive.  Trading that 250 watt+ 
power hog in on a 25 or 30 watter that is digitally sharp seems like a no 
brainer to me.  Unforch, all I can buy today at Wallies is 23" hidef wide.  
That is patently too darned big for a coco, any vintage.  Very effectively 
destroying the coconess of the image.  Trolling evilbay may turn up 
something suitable though.
 
> Thanks
> 
> 
> Bill Pierce
> "Today is a good day... I woke up" - Ritchie Havens
> 
> 
> My Music from the Tandy/Radio Shack Color Computer 2 & 3
> https://sites.google.com/site/dabarnstudio/
> Co-Webmaster of The TRS-80 Color Computer Archive
> http://www.colorcomputerarchive.com/
> Co-Contributor, Co-Editor for CocoPedia
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Cheers, Gene Heskett
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