Northstar problems
Richard A. Cini
I decided to pull out my Northstar, which has had problems in the past,
and play around with it. The biggest challenge seems to be getting the disks
to work reliably.
The controller that came with the unit is an MDS-AD3 double-density
controller I have an MDC-A4 lying around, too. The system originally had 48k
of memory but I discovered that the last 16k board had a stuck address bit
so I pulled it.
I'm able to boot with a DOS 5.0 diskette (SSSD) and a directory listing
shows it contains the standard "master diskette" programs.
I put a brand new 10-sector diskette into the second drive and
initialized it with "IN 2" which will format it double density.
Then, I perform a "GO CD 1 2" to copy the master disk to the blank. By
the shifting drive select lights, it appears to copy, but when I do "LI 2"
to list the directory on the new diskette, all I get is "T1 D2 S 0" which I
interpret as an error on track 1. The diskette is a brand new (from a sealed
pack).
Any ideas as to where I should be looking now?? I think the MDC-A4
controller is a single-density controller -- is it a "drop-in" replacement
or would it require software changes to work?
Thanks!!
Rich
Dave Dunfield
>controller I have an MDC-A4 lying around, too. The system originally had 48k
>of memory but I discovered that the last 16k board had a stuck address bit
>so I pulled it.
N*DOS should boot in less memory, although you may need to change the
top of memory configuration in BASIC if you plan to use it. CP/M may be
configured for the upper 16k and not boot without reconfiguring it.
> I'm able to boot with a DOS 5.0 diskette (SSSD) and a directory listing
>shows it contains the standard "master diskette" programs.
> I put a brand new 10-sector diskette into the second drive and
>initialized it with "IN 2" which will format it double density.
After you do this, try "LI 2" - and see if you get a blank directory. If not,
try putting the blank disk in drive 1, then do "IN 1" and "LI" to see if you
can get a blank directory from it (you can use these commands without
a "system disk" in drive 1).
If you can, then you can write to drive 1, so drive 2 may be faulty.
Use the "CR" command to make a file on the disk just so you can see
it, and confirm that you can see it with "LI" - then move the disk to drive
2 and see if you can "LI 2" to see the directory from it.
> Then, I perform a "GO CD 1 2" to copy the master disk to the blank. By
>the shifting drive select lights, it appears to copy, but when I do "LI 2"
>to list the directory on the new diskette, all I get is "T1 D2 S 0" which I
>interpret as an error on track 1. The diskette is a brand new (from a sealed
>pack).
If you can write to drive-1 but not 2, the drive if faulty - perhaps it just
needs a cleaning - if you can't write to either, then you may have a
controller issue.
You could also try swapping the drives (note, unlike PC drives, you
don't physically swap them on the cable - just switch the drive select
jumpers).
> Any ideas as to where I should be looking now?? I think the MDC-A4
>controller is a single-density controller -- is it a "drop-in" replacement
>or would it require software changes to work?
The MDC-A4 is a single-density controller, and the MDS-AD3 that you
have is a double-density controller - very different hardware.
You will need a single-density version of N*DOS, denoted by an 'S'
in the version (ie: 5.1S ). I have images of various N*DOS versions
(single and double density) on my site - If you can write your drive-1
then you should be able to make a 5.1S boot disk.
Btw - if you do determine it's a controller problem. All the N* controllers
that I have are fully socketed, and I've found that to be a sounrce of
trouble - several times over the years I've had to remove all the chips
and clean the leads and sockets (one at a time of course).
Dave
--
dave09@ Low-cost firmware development tools: www.dunfield.com
dunfield. Classic computer collection: www.classiccmp.org/dunfield
com
Richard A. Cini
On 10/4/09 4:01 PM, in article haavf8$pet$1...@aioe.org, "Dave Dunfield"
<Dave.D...@use.techsupport.link.on.my.website> wrote:
> Btw - if you do determine it's a controller problem. All the N* controllers
> that I have are fully socketed, and I've found that to be a sounrce of
> trouble - several times over the years I've had to remove all the chips
> and clean the leads and sockets (one at a time of course).
It's funny you mention this. The chips on my board have some serious oxide
on them. What do you use to clean them?
Rich
JackRubin
> On 10/4/09 4:01 PM, in article haavf8$pe...@aioe.org, "Dave Dunfield"
>
> <Dave.Dunfi...@use.techsupport.link.on.my.website> wrote:
> > Btw - if you do determine it's a controller problem. All the N* controllers
> > that I have are fully socketed, and I've found that to be a sounrce of
> > trouble - several times over the years I've had to remove all the chips
> > and clean the leads and sockets (one at a time of course).
>
> It's funny you mention this. The chips on my board have some serious oxide
> on them. What do you use to clean them?
>
> Rich
Pull the chips and put a drop of Caig DeOxit on each socket hole.
DeOxit is available in a small bottle with a fine tip applicator so
this really isn't too bad a job - I just run it down each side of the
socket and it wicks into the contact cavities. Replacing the chips
applies it to the chip legs. While you have the card out, put a _very_
light coat of NyLube or Dow #4 dielectric grease on the contact
fingers and try it out. Worst case, you'll be able to get the card out
more easily for further work!
Jack
Richard A. Cini
e26c7105-6cc0-4d6c...@j24g2000yqa.googlegroups.com, "Jack
Rubin" <jack....@ameritech.net> wrote:
> Pull the chips and put a drop of Caig DeOxit on each socket hole.
> DeOxit is available in a small bottle with a fine tip applicator so
> this really isn't too bad a job - I just run it down each side of the
> socket and it wicks into the contact cavities. Replacing the chips
> applies it to the chip legs. While you have the card out, put a _very_
> light coat of NyLube or Dow #4 dielectric grease on the contact
> fingers and try it out. Worst case, you'll be able to get the card out
> more easily for further work!
>
> Jack
Jack --
Thanks! I found DeOxit at Parts-Express but I'm still looking for the
other. I see that Caig has a "fader lube" which to me looks like the old
lubricated tuner cleaner. Would that work? Mouser, MCM, Newark and Digi-Key
don't have Dow #4 or NyLube. Any ideas before I start scouring the Net for
it?
Rich
Barry Watzman
kind of grease on the S-100 contact pins. Keep in mind that if you
screw up the S-100 connectors on the motherboard ..... well, you can
probably figure out the consequences.
JackRubin
> On 10/10/09 10:44 AM, in article
>
> Rubin" <jack.ru...@ameritech.net> wrote:
> > Pull the chips and put a drop of Caig DeOxit on each socket hole.
> > DeOxit is available in a small bottle with a fine tip applicator so
> > this really isn't too bad a job - I just run it down each side of the
> > socket and it wicks into the contact cavities. Replacing the chips
> > applies it to the chip legs. While you have the card out, put a _very_
> > light coat of NyLube or Dow #4 dielectric grease on the contact
> > fingers and try it out. Worst case, you'll be able to get the card out
> > more easily for further work!
>
> > Jack
>
> Jack --
>
> Thanks! I found DeOxit at Parts-Express but I'm still looking for the
> other. I see that Caig has a "fader lube" which to me looks like the old
> lubricated tuner cleaner. Would that work? Mouser, MCM, Newark and Digi-Key
> don't have Dow #4 or NyLube. Any ideas before I start scouring the Net for
> it?
>
> Rich
Sorry - I left out part of the Dow product number - should be DC#4 -
here's a more thorough discussion from earlier this year on cctalk -
http://archive.netbsd.se/?ml=cctech&a=2009-08&t=11293771
Nye makes an incredible range of synthetic lubricants - I'm still
working from a quart bottle that is probably 15-20 years old - so
finding the Dow product should be a lot easier. These lubes are
designed to lower insertion force and prevent oxidation of contacts
(the Nye product I'm using is used on things like elevator contacters
to prevent arcing) but also work well in low amperage situations. Look
at Dwight's and John's results in the attached reference for the
numbers. The contact-to-contact wiping force in a well designed
connector and undamaged connector displaces the lubricant on
insertion. These products are not designed to provide a conductive
path but rather to let the connectors do their job in an
uncontaminated environment.
Jack
Jack
Richard A. Cini
05e5f9b3-016e-44f8...@x37g2000yqj.googlegroups.com, "Jack
Rubin" <jack....@ameritech.net> wrote:
> Sorry - I left out part of the Dow product number - should be DC#4 -
> here's a more thorough discussion from earlier this year on cctalk -
>
> http://archive.netbsd.se/?ml=cctech&a=2009-08&t=11293771
>
> Nye makes an incredible range of synthetic lubricants - I'm still
> working from a quart bottle that is probably 15-20 years old - so
> finding the Dow product should be a lot easier. These lubes are
> designed to lower insertion force and prevent oxidation of contacts
> (the Nye product I'm using is used on things like elevator contacters
> to prevent arcing) but also work well in low amperage situations. Look
> at Dwight's and John's results in the attached reference for the
> numbers. The contact-to-contact wiping force in a well designed
> connector and undamaged connector displaces the lubricant on
> insertion. These products are not designed to provide a conductive
> path but rather to let the connectors do their job in an
> uncontaminated environment.
Jack --
As always, a great source of information and advice. To avoid the
potential problems that Barry implies, how do you apply it -- a dab on a
lint-free rag and then apply it to the board's edge connector?
Rich
dke...@hotmail.com
> On Sun, 18 Oct 2009 20:34:17 -0400, "Richard A. Cini"> >05e5f9b3-016e-44f8-ae71-fab8e3b32...@x37g2000yqj.googlegroups.com, "Jack
> plastics... such as the card edge connector bodies. Now THAT would be
> a disaster!- Hide quoted text -
>
> - Show quoted text -
Huh?
McMaster-Carr list DC#4 ( Dow Corning 4 ) as Cat# 1204K12 in single
tubes for $13.42 each. You could buy a gal for $242.11. Most
commercial
electrical shops carry it as well.
I first used it on my Poly-88 when I first got it ( about a year and
a half
after it was made ). To this day, it works fine and the only issue
I've
had is the main power supply capacitor was failing for poor ESR. I've
many times use this chassis as a test bed for other boards. I've
never had a crushed socket pin, cracked socket or pin contact
failure.
If the socket is already cracked, it won't help but for contacts,
I've
not had any issues.
Those that I've convinced to use it are quickly sold on its value.
Check
out what John Robertson has to say. He uses it on pinball machines
and has a lot more to risk than replacing an edge connector.
Dwight
Richard A. Cini
1cd6a760-61c2-4df8...@s21g2000prm.googlegroups.com, "Dwight
Elvey" <dke...@hotmail.com> wrote:
> Huh?
> McMaster-Carr list DC#4 ( Dow Corning 4 ) as Cat# 1204K12 in single
> tubes for $13.42 each. You could buy a gal for $242.11. Most
> commercial electrical shops carry it as well.
I always forget about McMaster. Just ordered a tube. Thanks for unsticking
those bits for me!
Rich