[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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>>>> http://five.pairlist.net/mailman/listinfo/coco

>>>>

>>>

>>>

>>> -- 

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>>

>>

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>>

>

>

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