[Coco] Back to the COCO

Wed Jan 4 15:13:07 EST 2017

Dave,
As Jim has indicated the drive from the 6x09 is not very high and just the capacitance from the ribbon cable over a short distance can cause stability issues. 
In other systems that use ribbon cable I am sure they have some good strong drivers.
What typically blows is when the +12V hits the NMI line, that too takes out the buffer IC which just gets replaced. That is the worst case scenario. Many times there are stuck address or data lines to 5v or gnd or just defective, that I am buffered from and just let them sit till I find it with the scope.
The +12V to NMI happens on a misalignment in the MPI to CC3.
Regards, Mark Marlette
 http://www.cloud9tech.com
mark at cloud9tech.com
mark at gamecamaddict.com

      From: Dave Philipsen <dave at davebiz.com>
 To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com> 
 Sent: Wednesday, January 4, 2017 12:44 PM
 Subject: Re: [Coco] Back to the COCO

No, no, I'm certainly not knocking your product.  I'm sure it is 
appropriate for certain users.  I, personally, have never blown a CPU in 
a CoCo and I've made a bunch of homemade and/or modified things that 
plugged into the cartridge port including a _hand-taped_ board I once 
designed before CAD was affordable.  And I've removed a number of good, 
working CPUs from CoCos only to replace them with a socket so that a 
6309 could be used.

I have a question though.  If you replace a CPU with a Protector board 
and the bus is exposed to the same types of abuse that caused the CPU to 
go out, what does that abuse do to the drivers on the Protector board?

Dave

On 1/4/2017 12:34 PM, Mark Marlette wrote:
> Dave,
> It probably depends on what you do with your CoCo.
> I plug questionable hardware all the time into the CoCo, so peace of mind, $25 ..... yep.
> Having fixed hundreds of CoCos over the years, looks like others should have done the same! :)
> YMMV.
> Regards, Mark Marlette
>  http://www.cloud9tech.com
> mark at cloud9tech.com
> mark at gamecamaddict.com
>
>        From: Dave Philipsen <dave at davebiz.com>
>  To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
>  Sent: Wednesday, January 4, 2017 10:12 AM
>  Subject: Re: [Coco] Back to the COCO
>    
>
>
> On 1/4/2017 10:02 AM, Brian Blake wrote:
>> Bill,
>>
>> I'm not sure I've ever seen a buffered 'y' cable before - it would
>> only buffer the device being plugged into the CoCo anyhow. The best
>> solution to protect the CoCo, IMHO, would be to install the Cloud9
>> Protector - CPU replacement board that has buffering IC's in place
>> already.
> I'm not disagreeing with your premise that the Protector will, indeed,
> protect the CPU but the Protector costs 25 bucks plus shipping and one
> could probably by a lifetime supply of 6809s or 6309s for that price.
> You can find 6809s and 6309s on eBay for 2-5 dollars.  How many times
> have you had a CPU die on you?  Once, twice?
>
> Dave
>
>
>>
>> On 1/4/2017 10:35 AM, Bill Gunshannon wrote:
>>> Funny you should mention that.  After seeing the comment about the
>>> COCO3 not having the 12v
>>> required by the old floppy controller I got to wondering if it might
>>> not be better just running them
>>> off of wall warts anyway.
>>>
>>> If you could, send me a private email with your real mail address and
>>> I will see if I can dig up
>>> boxes. (won't fit in even a large flat rate box! :-( )  Feel free to
>>> pull out any chips you suspect
>>> and put in sockets.  I will gladly pay for the repairs as long as it
>>> doesn't end out exceeding
>>> the actual cost of a new one.  :-)
>>>
>>> And now another question for you or any of the other serious COCO
>>> hardware guys.
>>> The MPI apparently has no more buffering than the cartridge port
>>> itself.  The Glenside
>>> IDE has two open ports but also has no form of buffering either.
>>> Just how hard would
>>> it be to make something like the infamous Y-cable on a circuit board
>>> only with buffering
>>> to protect the COCO from damage?  Getting PC boards is easy anymore
>>> with sites like
>>> OSK (I have a handful of the cartridge boards and that is how I my
>>> Drivewire).  Is it
>>> reasonable?
>>>
>>> bill
>>> ________________________________________
>>> From: Coco [coco-bounces at maltedmedia.com] on behalf of camillus gmail
>>> [camillus.b.58 at gmail.com]
>>> Sent: Wednesday, January 4, 2017 10:00 AM
>>> To: Bill via Coco
>>> Subject: Re: [Coco] Back to the COCO
>>>
>>> Hi, Bill.
>>>
>>> That sounds like a plan, and you may even take out the transformer of
>>> the broken one too. I power my coco's with a wall adapter, so I do
>>> not need the transformer.
>>>
>>> I do need to tell you that the only way to tell if the cpu is dead is
>>> to take it out and replace it with a known good one. The fact that
>>> most of them are soldered directly to the board and removing them
>>> without harm is practically zero. I do have a couple of 6309 which
>>> are pin compatible and function the same. Those cpu's goes around for
>>> 8 to 12 $.
>>>
>>> If the GIME is shot, then that is an other animal to slaughter. Those
>>> can only be replaced by existing chips from coco3's that are broke
>>> but still have a good GIME.
>>>
>>> The pia's are still to find on the net.
>>>
>>> So lets hope it is just a minor problem.
>>>
>>> cb
>>>
>>> On 1/4/2017 8:48:11 AM, Bill Gunshannon <bill.gunshannon at hotmail.com>
>>> wrote:
>>> On 1/3/17 10:40 PM, camillus gmail wrote:
>>>> HI Bill.
>>>>
>>>> I would love to look at them, the only cost would be the shipping to
>>>> indiana.
>>>>
>>>> I have two coco3 working, so I can swap out part to test.
>>>>
>>>> This is my hobby and I do not charge for this.
>>>>
>>>> Unless of course you consider to let me keep one of the coco's for
>>>> the keyboard and the case?
>>>>
>>>> Let me know ho this sound for you
>>> OK. let's try this....
>>>
>>> How about if I send you one complete broken COCO3 that would be yours
>>> to keep and include in the package two additional broken COCO3 circuit
>>> boards for repair (assuming reasonable in both cost and needed work)
>>> and return? Not shipping the two additional cases (and the
>>> transformer) would reduce the cost. Doable?
>>>
>>> bill
>>>
>>>
>>>
>>>
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>>>
>>
>

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