[Coco] Coco in France
camillus.b.58 at gmail.com
Mon Feb 11 14:22:25 EST 2019
I can be wrong but to me there is nothing in the schematics that let me believe there is any mains sync.
I do know that there is some signal that is from one off the pia's that is 50/60 hertz, but that is cpu controlled, not mains.
All power is from designated regulators 12v, 8v and 5v., which means all power sources are DC.(some ripple discarded)
The person mentioned that screen came or come up for a split second, and the cassette relay comes up.
Could it be something in his tv set that is refusing signal?
Like I said in a earlier message, he can connect it to a native normal tv set, and should have black&white image, maybe not the best quality either, but hey at least you know the coco works.
On 02/11/19 6:06:14 AM, Carlos Camacho <idevgames at gmail.com> wrote:
Well, it looks like his power transformer only steps the voltage down to
110V but doesn't alter the frequency. So that remains at 50hz.
Refresh my memory... the CoCo needs 60hz in order to generate it's NTSC RF
video correct? And as I tap into the video signal just before it goes to
the RF modulator for composite out, that would explain why no video there
He says a transformer that converts to 60hz is expensive so is wondering
about replacing the internal transformer. Frankly, for me, I'd prefer
spending the money on a good external transformer and not risk my retro
Interesting that he is using same transformer with C64 and other retro
machines without issues.
Anyhow, I just need confirmation on 60hz power requirement.
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