[Coco] CoCo2 vs CoCo3 changes

[Zippster]

Sounds like an electrolytic cap possibly.  Look at C54, a 470uF ac coupling
cap for the composite out as a possible suspect.

Any electrolytics in the signal paths I would swap out at this point just to eliminate
them.  They usually work, but are way past their expected service life at this point.

- Ed


> On Jul 18, 2018, at 12:06 PM, Kevin Becker <kevin at kevinbecker.org> wrote:
> 
> At first the composite video was very wavy and noticeably worse than RF
> input but that seemed to clear up after it warmed up, strangely.  At one
> point composite seemed to stop working at all but it came back after a few
> power cycles and swapping TV inputs a few times.  After giving up on CoCo 3
> games I tried Buzzard Bait, which I knew worked on my CoCo 2, and I could
> hear it playing but the screen wasn't updating and was a little out of
> whack.  When I went back to RF Buzzard Bait played fine.
> 
> 
> 
> 
> 
> On Wed, Jul 18, 2018 at 12:56 PM, rietveld rietveld <rietveldh at hotmail.com>
> wrote:
> 
>> 'composite issues '?   ‎Does it display in a semi black and white?   I
>> found that my coco3 and Dragon 64 both have display issues with certain
>> tv/monitors that use comp in.   Some work perfectly others didn't
>> 
>> Sent from my BlackBerry 10 smartphone.
>>  Original Message
>> From: Kevin Becker
>> Sent: Wednesday, July 18, 2018 11:10 AM
>> To: CoCoList for Color Computer Enthusiasts
>> Reply To: CoCoList for Color Computer Enthusiasts
>> Subject: Re: [Coco] CoCo2 vs CoCo3 changes
>> 
>> 
>> Thanks, these look great.
>> 
>> Apparently my new CoCo 3 isn't working so well though so it may be some
>> time before I really get to dig into it.  I plugged it in last night and
>> had a lot of weird composite video issues.  Maybe it just doesn't like my
>> TV.  The RF output seems to work fine.  I haven't been able to successfully
>> run any CoCo 3 software either though.  It seems to crash or not load at
>> all.  I did run a memory test successfully so I've got some digging to do
>> to figure out what is going on.
>> 
>> On Wed, Jul 18, 2018 at 7:22 AM, Frank Swygert <farna at amc-mag.com> wrote:
>> 
>>> On 17/7/2018 14:02, Kevin Becker wrote:
>>>> So I finally broke down and bought a CoCo 3 on eBay.  It arrived today
>>> but
>>>> I haven't had a chance to try it out yet since I'm at work.  It
>> suddenly
>>>> occurred to me though that I don't actually know that much about the
>> CoCo
>>>> 3.  I had a CoCo 2 back in the 80s and I bought a CoCo 2 last winter
>> that
>>>> I've been having fun with.
>>>> 
>>>> I know it has more RAM, different keyboard layout, composite and RGB
>>>> video.  I know the GIME provides better graphics.  Anything else I
>> should
>>>> know?  I'm especially curious about the MicroWare additions to BASIC to
>>>> support the improved graphics.  Should I just RTFM or is there any sort
>>> of
>>>> quickstart list of things to know for someone upgrading from CoCo 2 to
>> a
>>>> CoCo 3?
>>> 
>>> =========================================
>>> 
>>> The "Unravelled" series of books for all three CoCos are in the link
>>> below. You might want to start with the "Super Extended BASIC Unravelled"
>>> to see how all the new commands work.
>>> http://www.colorcomputerarchive.com/coco/Documents/Books/Unravelled%
>>> 20Series/
>>> 
>>> This should help also. Was printed right after the CoCo3 came out:
>>> http://www.colorcomputerarchive.com/coco/Documents/Books/Coco%20III%
>>> 20Secrets%20Revealed%20(Microcom%20Software).pdf
>>> 
>>> 
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>>> 
>> 
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