[Coco] CoCo2 vs CoCo3 changes

Wed Jul 18 14:03:17 EDT 2018

Electrolytic caps have a finite life span, being used or not. Visible 
signs are hard to spot. Newer caps have stress cuts on the top, that let 
the cap buldge as it gets bad which is one sure sign. Leaking can be a 
sign, but it could just be goo that was put on there to glue them down. 
If you have a scope, or a good volt meter, you could look for ac ripple 
on the power side. In my opinion, electrolytic caps over 20 years are 
just a bomb waiting to go off. I bought two of those kits and changed 
mine for good measure.

On 7/18/2018 10:52 AM, Jack Carpenter via Coco wrote:
> What are the sign of capacitor going bad?
>   
>
>      On Wednesday, July 18, 2018, 5:36:26 PM GMT, Kevin Becker <kevin at kevinbecker.org> wrote:
>   
>   Thanks!  I thought I had seen them somewhere but I didn't think to check
> eBay.
>
> On Wed, Jul 18, 2018 at 1:26 PM, Zippster <zippster278 at gmail.com> wrote:
>
>> Someone on eBay has apparently.  Not sure the link will survive the list
>> processing, but…
>>
>> link <https://www.ebay.com/itm/TRS-80-Tandy-Color-Computer-2-
>> Tandy-Color-Computer-3-Capacitor-Replacement-Kit/232472882664?hash=
>> item362076ade8:g:~ocAAOSwmhJZqwGI:sc:USPSFirstClass!55021!US!-1&_
>> sacat=0&_nkw=trs80+computer+capacitor+kit&_from=R40&rt=nc&
>> LH_TitleDesc=0%7C0>
>>
>> - Ed
>>
>>
>>> On Jul 18, 2018, at 12:14 PM, Kevin Becker <kevin at kevinbecker.org>
>> wrote:
>>> I don't suppose anybody has put together a CoCo3 capacitor kit to make it
>>> easy to order them all at once?
>>>
>>> On Wed, Jul 18, 2018 at 1:11 PM, Zippster <zippster278 at gmail.com> wrote:
>>>
>>>> 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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-- 
Tim Fadden
"Hey Schmidt, don't forget about the six P's.
Proper Preparation Prevents Piss-Poor Performance!"