[Coco] calling all MM/1 owners

[Bob Devries]

yeah, looks like I'm going to have to do some careful unsoldering. Not 
looking forward to that, since these are multi-layered boards.

--
Regards, Bob Devries, Dalby, Queensland, Australia

Isaiah 50:4 The sovereign Lord has given me
the capacity to be his spokesman,
so that I know how to help the weary.

website: http://www.home.gil.com.au/~bdevasl
my blog: http://bdevries.invigorated.org/

----- Original Message ----- 
From: "Joel Ewy" <jcewy at swbell.net>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Friday, January 25, 2008 2:18 PM
Subject: Re: [Coco] calling all MM/1 owners


> Bob Devries wrote:
>> Joel, as far as I know, the termination resistors have a power and a
>> ground pin at opposite ends with a number of pairs of 220 and 330 ohm
>> resistors strung between them. The centre point of these pairs is
>> connected to the SCSI bus data/control lines. Yes, having them
>> backwards would make some difference, but how much? Certainly it
>> appears that it's not enough to stop the SCSI cold.
>>
> Sounds like you need to do some rework on your I/O board.  :-(  I'd
> offer to send you some parts but it probably doesn't make sense to ship
> to Australia from central Kansas.  (There ought to be some kind of
> tornado-powered Oz to Oz express wormhole...)  I still have MM/1 I/O
> board parts, though I have it in the back of my mind that the
> terminators for the SCSI interface may have changed to a different
> package between the board you have and the ones I was going to produce.
> And I have a rail of unused DS1287As -- brand new in about 1994.
>
> JCE
>> -- 
>> Regards, Bob Devries, Dalby, Queensland, Australia
>>
>> Isaiah 50:4 The sovereign Lord has given me
>> the capacity to be his spokesman,
>> so that I know how to help the weary.
>>
>> website: http://www.home.gil.com.au/~bdevasl
>> my blog: http://bdevries.invigorated.org/
>>
>> ----- Original Message ----- From: "Joel Ewy" <jcewy at swbell.net>
>> To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
>> Sent: Friday, January 25, 2008 1:54 PM
>> Subject: Re: [Coco] calling all MM/1 owners
>>
>>
>>> Bob Devries wrote:
>>>> I just removed the I/O board from the MM/1 to more closely examine the
>>>> RTC.
>>>>
>>>> I found that one of the termination resistors for the SCSI bus is
>>>> oriented the opposite way to the other two. RN5, the middle one is
>>>> different. Now I'm wondering what effect this will have on the working
>>>> of the SCSI bus? Could this be my problem?
>>>>
>>>> Joel, the termination resistor's 'notch' or 'dot' end should be in the
>>>> solder pad that's square, am I correct?
>>>>
>>> Yeah, that's right.  I think that's the common lead for the resistors.
>>> Resistors themselves aren't directional.  Does it make a difference
>>> because of the way they're assembled in an array?
>>>
>>> JCE
>>>> -- 
>>>> Regards, Bob Devries, Dalby, Queensland, Australia
>>>>
>>>> Isaiah 50:4 The sovereign Lord has given me
>>>> the capacity to be his spokesman,
>>>> so that I know how to help the weary.
>>>>
>>>> website: http://www.home.gil.com.au/~bdevasl
>>>> my blog: http://bdevries.invigorated.org/
>>>>
>>>> ----- Original Message ----- From: "Dave R in Illinois"
>>>> <lazyhand at sbcglobal.net>
>>>> To: <coco at maltedmedia.com>
>>>> Sent: Thursday, January 24, 2008 12:03 PM
>>>> Subject: [Coco] calling all MM/1 owners
>>>>
>>>>
>>>>> Have you checked to make sure the drive / cable is properly
>>>>> terminated? I've
>>>>> seen corroded pins on terminators do strange things to raid arrays. I
>>>>> never
>>>>> owned a mm1 so I am not sure if there even is one, I would assume
>>>>> there
>>>>> would be.
>>>>>
>>>>>
>>>>>
>>>>> -Dave
>>>>>
>>>>>
>>>>>
>>>>> ______________________________________________________
>>>>>
>>>>>
>>>>>
>>>>> I have a small problem with my MM/1, and I'm wondering if there was
>>>>> ever a
>>>>> fix for it?
>>>>>
>>>>> When I power it up, the computer goes through its procedure to try to
>>>>> boot
>>>>> from the floppy, and then from the SCSI hard disc. It *always* locks
>>>>> up the
>>>>> SCSI bus at that point, and pressing reset does not unlock it. I
>>>>> need to
>>>>> cycle the power to unlock it. It then usually fires up correctly, but
>>>>> not
>>>>> always.
>>>>>
>>>>> My MM/1 is a 3MB with the expansion board. It has a 170MB Quantum SCSI
>>>>> drive. The drive itself initialises properly (at least, it makes
>>>>> all the
>>>>> right noises).
>>>>>
>>>>> Comments anyone?
>>>>> -- 
>>>>> Regards, Bob Devries, Dalby, Queensland, Australia
>>>>>
>>>>> Isaiah 50:4 The sovereign Lord has given me
>>>>> the capacity to be his spokesman,
>>>>> so that I know how to help the weary.
>>>>>
>>>>>
>>>>> -- 
>>>>> Coco mailing list
>>>>> Coco at maltedmedia.com
>>>>> http://five.pairlist.net/mailman/listinfo/coco
>>>>
>>>>
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>>>
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>
>
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