31 Dec
2002
31 Dec
'02
7:55 a.m.
While attempting to revive a Compaq 286/SLT laptop for use as a
front-end for my UP600a programmer, I have found that the battery
on the DS1287 has died (no suprise there). What sucks is that
even after I run the floppy-based setup utility, after a reboot
(not a power-off cycle), the machine forgets what I just set,
both the data and time, and the geometry of the A: drive. Seeing
as how it thinks there's a 5.25" floppy and it's really a 3.5"
high-density drive at the end of the cable, as you can imagine,
it won't reliably read disks.
So... I have ordered a replacement DS12887 since they no longer make/ship
the DS1287. Couple of interesting app notes here:
http://www.maxim-ic.com/appnotes.cfm/appnote_number/562
http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2681
What I'm wondering is if anyone on the list has ever replaced a DS1287
with a DS12887. One of the sheets seems to suggest that I'll need
an updated BIOS ROM (clearly not available for a 286 laptop) to drive
the extra stuff associated with the enhanced century rollover.
Alternatively, has anyone here successfully performed surgery on a Dallas
module? I have disconnected the battery from a Mostek 48T02 from a SPARC
and soldered on an external Lithium cell, but the packaging makes it easy
to get access to the battery wires coming down from the top (I even put
the battery on a 9V battery snap so it's easier to replace) I haven't
heard of anyone doing this for the more sealed Dallas modules.
So... anybody else suffer though this?
-ethan
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31 Dec
31 Dec
3:19 p.m.
A while back I had problems accessing a Grid 1520-286
because of a password. If I remember correctly it was a
DS1287A. The A signified it as resettable and grounding
2 pins cleared the memory. Your problem would seem to
stem more from the BIOS settings and it is going to the
default setting and since the Dallis chip is dead nothing
is retained. ISTR that the 12887 is a drop-in replacement.
If you want to call soldering all those pins "drop-in"
Dallas has a bunch of info on the chip. I don't have the
URL handy.
Considering all the problems and low used prices
involved. You might consider getting an old Grid 1520
which also has the advantage of an additional EPROM
slot which can contain info configuring various aspects of
the computer, including a system boot.
Lawrence
On 31 Dec 2002, , Ethan Dicks wrote:
While attempting to revive a Compaq 286/SLT laptop for use
as a front-end for my UP600a programmer, I have found that
the battery on the DS1287 has died (no suprise there). What
sucks is that even after I run the floppy-based setup
utility, after a reboot (not a power-off cycle), the machine
forgets what I just set, both the data and time, and the
geometry of the A: drive. Seeing as how it thinks there's a
5.25" floppy and it's really a 3.5" high-density drive at
the end of the cable, as you can imagine, it won't reliably
read disks.
So... I have ordered a replacement DS12887 since they no
longer make/ship the DS1287. Couple of interesting app
notes here:
http://www.maxim-ic.com/appnotes.cfm/appnote_number/562
http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2681
What I'm wondering is if anyone on the list has ever
replaced a DS1287 with a DS12887. One of the sheets seems
to suggest that I'll need an updated BIOS ROM (clearly not
available for a 286 laptop) to drive the extra stuff
associated with the enhanced century rollover.
Alternatively, has anyone here successfully performed
surgery on a Dallas module? I have disconnected the battery
from a Mostek 48T02 from a SPARC and soldered on an external
Lithium cell, but the packaging makes it easy to get access
to the battery wires coming down from the top (I even put
the battery on a 9V battery snap so it's easier to replace)
I haven't heard of anyone doing this for the more sealed
Dallas modules.
So... anybody else suffer though this?
-ethan
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May you get halfway to heaven, before Satan learns you're
dead or 3/4s of the way to the bar before your wife finds
you've gone out.
lgwalker(a)mts.net
bigwalk_ca(a)yahoo.com
1 Jan
1 Jan
3:48 a.m.
--- Lawrence Walker <lgwalker(a)mts.net> wrote:
A while back I had problems accessing a Grid 1520-286
because of a password. If I remember correctly it was a
DS1287A. The A signified it as resettable and grounding
2 pins cleared the memory.
I've seen that detail on the web pages.
Your problem would seem to
stem more from the BIOS settings and it is going to the
default setting and since the Dallis chip is dead nothing
is retained.
Exactly.
ISTR that the 12887 is a drop-in replacement.
If you want to call soldering all those pins "drop-in"
I do. Soldering is not offputting to me.
Dallas has a bunch of info on the chip. I don't
have the
URL handy.
I have those data sheets. I was curious to learn from others
experiences.
Considering all the problems and low used prices
involved. You might consider getting an old Grid 1520
which also has the advantage of an additional EPROM
slot which can contain info configuring various aspects of
the computer, including a system boot.
I wouldn't mind a Grid, but unless it has an ISA slot, preferably two,
it won't work for my application - I need an Ethernet interface for
getting EPROM and PLD data in and out, and the programmer interface.
The Compaq 286/SLT has two ISA slots in the docking station. I already
have the machine here, and I have a DS12887 coming as a free sample.
I appreciate the suggestion, but until I completely run this machine
to the ground, I would like to continue to explore using it.
Thanks,
-ethan
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8:11 a.m.
On Wed, 1 Jan 2003, Ethan Dicks wrote:
The Compaq 286/SLT has two ISA slots in the docking
station. I already
have the machine here, and I have a DS12887 coming as a free sample.
I appreciate the suggestion, but until I completely run this machine to
the ground, I would like to continue to explore using it.
Years ago I used to maintain some of these systems. I still have my old
SLT, but it was dropped, which broke the LCD backlights and did some other
unknown damage to the main board. I suspect a crystal or oscillator was
damaged. IIRC, the plastic stick-on film that covers the LCD was also
damaged, though the LCD itself is intact. I guess I could use a
replacement LCD for the system if someone has one laying around.
The memory modules are located center-front of the "laptop", under a metal
shield/cover. I don't remember how many slots exist, but I think it can
hold 3, maybe 4 modules. Modules were available in 1MB and 4MB sizes. The
hard drive is a 3.5" form factor IDE drive. Usually, these systems had a
20MB or 40MB drive, but it would have been possible to upgrade it to
120-210MB too. Without a custom BIOS, the system won't support user
definable drive types, so you have to use those "Compaq" re-branded Conner
drives, while making sure the particular type number is supported by the
system. It's also not uncommon for the original hard drives in these
systems to have numerous media defects. The drives that were used were not
exactly designed for portable use, so were easily damaged.
-Toth
8:50 a.m.
--- Tothwolf <tothwolf(a)concentric.net> wrote:
Years ago I used to maintain some of these systems...
The memory modules are located center-front of the "laptop", under a
metal shield/cover.
Yep. Found those. Full of SRAM, not DRAM, astonishingly enough.
I don't remember how many slots exist, but I think
it can
hold 3, maybe 4 modules. Modules were available in 1MB and 4MB sizes.
Three. I have three 1MB modules. Didn't know there were 4MB modules.
I'm sure I'll never run across any. For DOS usage, 3.6MB is OK. This
one has Windows 3.0 on it, but I don't need it for what I'm doing.
The hard drive is a 3.5" form factor IDE drive.
Usually, these systems
had a 20MB or 40MB drive, but it would have been possible to upgrade
it to 120-210MB too...
Mine has the bog-standard 40MB Connor drive (type 22). Would love to
find a set of replacement ROMs for this so I could use oddball drives,
but for now, I'm stuck with what I've got.
-ethan
P.S. - I got impatient/bored, so I carved the top of the DS1287 off,
bored out the battery and soldered on some wires to a lithium battery
holder. Not sure I can put the lid back on (used a low-profile socket,
but it's awfully close to the aluminum drive tray/RF sheild), but for
now, I have successfully loaded high-density floppies into it and
am staring at the up600 application menu!
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9:31 a.m.
New subject: Expansion slots in Grids was Re: Anyone have any experience replacing a Dallas 1287 with a 12887?
At 09:50 AM 1/1/03 -0800, Ethan wrote:
--- Lawrence Walker <lgwalker(a)mts.net> wrote:
Mine has two slots. IIRC one is a 16 bit ISA slot and the other is 8 bit. They're
both located in an expansion pod that hands on the bottom of the Grid.
Joe
A while back I had problems accessing a Grid
1520-286
because of a password. If I remember correctly it was a
DS1287A. The A signified it as resettable and grounding
2 pins cleared the memory.
I've seen that detail on the web pages.
Your problem would seem to
stem more from the BIOS settings and it is going to the
default setting and since the Dallis chip is dead nothing
is retained.
Exactly.
ISTR that the 12887 is a drop-in replacement.
If you want to call soldering all those pins "drop-in"
I do. Soldering is not offputting to me.
Dallas has a bunch of info on the chip. I
don't have the
URL handy.
I have those data sheets. I was curious to learn from others
experiences.
Considering all the problems and low used prices
involved. You might consider getting an old Grid 1520
which also has the advantage of an additional EPROM
slot which can contain info configuring various aspects of
the computer, including a system boot.
I wouldn't mind a Grid, but unless it has an ISA slot, preferably two,
it won't work for my application
2:13 p.m.
New subject: Expansion slots in Grids was Re: Anyone have any experience replacing a Dallas 1287 with a 12887?
--- Joe <rigdonj(a)cfl.rr.com> wrote:
At 09:50 AM 1/1/03 -0800, Ethan wrote:
Works for me. I'll be sure to pick one up the next time I see one
float by. Haven't seen them at Dayton in the past couple of years.
They used to be popular (and expensive).
For now, the Compaq 286/SLT is working for me. Looks a mess, though.
I have a picture (still in the camera) of the setup - the LCD and outer
shell are sitting above and behind the motherboard, which is open to
the world with the floppy drive off to one side and the hard disk resting
on a "Magical Mystery Tour" jewel case. The DS1287 has a crater in the
top with a 9V battery lead soldered to the rim, plugged into a lithium
cell in a ziplock baggie (which itself is soldered to the top of a 9V
battery). I don't intend for it to stay that way, but I was finally
able to a) program a GAL for the SBC6120 at last, and b) verify that
the software someone sent me for a Xander XP6007 _does_ work with the
UP600a (same ISA card, similar data files in the application directory).
Once my DS12C887 arrives, I'll be able to button it back up into a tidy
package presuming I don't have a wierd BIOS interaction issue.
Thanks one and all for help, pictures, zip files and spare parts.
-ethan
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I wouldn't mind a Grid, but unless it has an
ISA slot, preferably two,
it won't work for my application
Mine has two slots. IIRC one is a 16 bit ISA slot and the other is 8
bit. They're both located in an expansion pod that hands on the bottom of
the Grid.
6:34 p.m.
New subject: Expansion slots in Grids was Re: Anyone have any experience replacing a Dallas 1287 with a 12887?
On 1 Jan 2003, , Joe wrote:
Mine has two slots. IIRC one is a 16 bit ISA slot and the
other is 8 bit. They're both located in an expansion pod
that hands on the bottom of the Grid.
Joe
What model do you have Joe. The 15xx use pods in the
battery bay. I have VGA and AC pods and I know there
are ethernet and SCSI pods. (I have a SCSI 5.25 fdd but
alas not the pod). Is this one of the earlier Gridcase
models ? I'll have to keep an eye out for that one myself.
Lawrence
Considering all the problems and low used prices
involved. You might consider getting an old Grid 1520
which also has the advantage of an additional EPROM slot
which can contain info configuring various aspects of the
computer, including a system boot.
I wouldn't mind a Grid, but unless it has an ISA slot,
preferably two, it won't work for my application 
31 Dec
31 Dec
3:53 p.m.
New subject: Anyone have any experience replacing a Dallas 1287 with a 12887?
At 01:57 PM 12/31/02, Ethan Dicks wrote:
<snip>
Alternatively, has anyone here successfully performed
surgery on a Dallas
module? I have disconnected the battery from a Mostek 48T02 from a SPARC
and soldered on an external Lithium cell, but the packaging makes it easy
to get access to the battery wires coming down from the top (I even put
the battery on a 9V battery snap so it's easier to replace) I haven't
heard of anyone doing this for the more sealed Dallas modules.
So... anybody else suffer though this?
-ethan
Annoying surgery, not impossible. The battery's atop the IC, usually a
CR1220 or so type cell, soldered to a couple pins.
Not sure if I did this on a Dallas unit offhand, know I have done it on
epoxy-potted and on clip-on plastic cover type RTC's.
Myself, I put in a vertical battery holder and use CR2032's usually (Just
have to stock one battery, then.)
Mark
8025
days inactive
8027
days old
8 comments
5 participants
participants (5)
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erd_6502＠yahoo.com -
lgwalker＠mts.net -
rigdonj＠cfl.rr.com -
tothwolf＠concentric.net -
voyager＠iols.net