[Coco] CoCo in France

[Christopher R. Hawks]

On Sun, 10 Feb 2019 12:42:39 -0500
Neil Cherry <ncherry at linuxha.com> wrote:

> On 2/10/19 12:20 PM, Gene Heskett wrote:
> 
> > I'll make a SWAG here after putting on my CET hat, and say the big
> > electrolytic capacitor on the mainboard, not too far from the bigger
> > transistor on a heat sink of sorts was getting pretty well dried
> > out, and while it could hold a usable voltage during the low
> > voltage portion in a 60 hz wall supply, but is falling short on the
> > longer low voltage period of a 50 cycle supply. We tend to forget
> > that these things are 30+ years old, and the average life of such
> > is not measured in multiple decades.
> > 
> > Not to mention that the power transformer in the coco was a 60 hz
> > rated one, and is going to run 15 or so degrees F warmer on 50 hz,
> > due to the longer time the primary current has to build up,
> > approaching the saturation point of its iron core.
> > 
> > So at a minimum, that cap might need replaced.
> > 
> > If the iron does saturate magnetically the current flow in the
> > primary will rise to resistive limits and will likely toast the
> > transformer at some point, compared to the 100+ years it will run
> > on 60 hz. But IIRC there's a fuse on that little pcb which might
> > interrupt that.  If it clears, the coco will be completely dead.
> > I've only seen one of those fuses fail, so its not a common
> > occurrence on 60 hz power.
> > 
> > That capacitor, IIRC is a 4700 uf, and on 50 hz power, a 6800 uf
> > would be a better replacement.
> 
> +1, what he (Gene) said ... :-)
> 

+1 too (Two)


Christopher R. Hawks
HAWKSoft
-- 
"The politician was gone but unnoticed, like the period after the
 Dr. on a Dr Pepper can." 	 -- Wayne Goode, Madison, Alabama
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