[Coco] Coco 2 RF

[Luis Fernández]

I have it direct, Japanese to coaccial jack, there are also adapters
but it is only + with + and - to -, try it 

> To: coco at maltedmedia.com
> From: haywire666 at aol.com
> Date: Tue, 14 Feb 2012 22:53:09 -0500
> Subject: Re: [Coco] Coco 2 RF
> 
> 
> All this talk about coco2 rf reminded me... I have 3 coco 2's I never or rarely use because the rf is pretty bad.
> 
> 
> Dosn't someone have a circuit for coco2 (someone shared one on coco3.com but it only works on coco1)
> To produce video and audio signals? I'd like to mod my coco2's with a couple of rca jacks in the back with 
> audio and video outputs if possible...
> 
> Steven
> 
> 
> -----Original Message-----
> From: gene heskett <gheskett at wdtv.com>
> To: coco <coco at maltedmedia.com>
> Sent: Tue, Feb 14, 2012 7:30 pm
> Subject: Re: [Coco] Coco 2 RF
> 
> 
> On Tuesday, February 14, 2012 07:02:53 PM Jeremy Michea did opine:
> 
> > “As for your problem, I have never seen it, but since I am a CET, my
> > best guess would be a dried out capacitor in your coco's video
> > circuitry, causing the modulation to be much less than the 90% or so it
> > was designed for, which in turn gives a very low contrast, and likely
> > hard to sync to, image on a tv.â€‌
> > 
> > Thanks Gene. That was kind of what I was looking for. I guess I still
> > wasn’t wording the question properly as some assumed I didn’t know
> > if Composite was simply better. It was more of wondering if it was
> > simply a matter of the poor RF or if there was a deeper issue. For the
> > record, I’m more than aware that composite is better quality than RF.
> > I didn’t fall off the coco turnip truck yesterday
> > 
> > Sadly though I don’t have an oscilloscope. Assuming the problem is the
> > one you describe would it simply be a matter of desoldering the old
> > capacitor and soldering in a new one? Unfortunately I don’t have the
> > soldering skills. I’ve never done it before although I have been
> > wanting to learn, just not enough hours in the day at the moment.
> > Thanks Gene for the answer though I appreciate it.
> 
> You could just form the leads of a somewhere near the same sized 
> cap(acitor), and paying attention to the polarity markings on both, connect 
> the test cap across the likely suspect and check the tv to see if it helps.  
> Don't be surprised if it still helps after the test cap has been removed.  
> What has happened in that event is the that the charging currents from one 
> cap to the other, have caused a momentary nano-weld between the foil of the 
> suspected cap and its lead where they are connected internally.  It won't 
> last long, sometimes only minutes, but that is the response that nails that 
> particular perp to the guilty list.
> 
> Bear in mind also that safe to use around electronics type soldering tools 
> are not the shacks strongest suites, it s/b temperature controlled (most 
> get several hundred degrees too hot if left turned on for 20 minutes) and 
> should have a 3 wire line cord, claiming a static grounded tip.  My fav 
> iron is sold by GC and their ilk for around $150 these days, and has a 
> meter reading in real temps as measured by a platinum sensor touching the 
> back end of the tip insert, and a dial knob to set the temp with, which it 
> will then hold within 10F or thereabouts.  It isn't the greatest iron, but 
> I've had it for going on 25 years and it still works great after probably 
> 10,000 hours of on time.  It, or duplicates of it, have earned me close to 
> a million spread over the last 30 years while I was keeping a tv station on 
> the air.
> 
> When tracing the schematic looking for likely suspects, keep in mind that 
> the cap(s) I am thinking of would be somewhere in the path that could 
> effect the rf output, but not the composite, so that should narrow the 
> search to just 4 or 5 of the 80 or so caps in a coco.  Further narrowing by 
> eliminating anything that is not an electrolytic type should get you down 
> to 2 at most, and likely only one.
> 
> HTH, Jeremy.
> 
> Cheers, Gene
> -- 
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> My web page: <http://coyoteden.dyndns-free.com:85/gene>
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> 	In the fight between you and the world, back the world.
> 		-- Franz Kafka, "RS's 1974 Expectation of Days"
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