29 Dec
2005
29 Dec
'05
3:41 a.m.
ISTR somebody recently mentioned soldering battery leads to two legs
of a Dallas CMOS clock chip. Does that ring any bells?
I'm fiddling with a Compaq SLT/286 whose Dallas module is very dead.
I'd like to fix it.
Doc
29 Dec
29 Dec
3:47 p.m.
On Thursday 29 December 2005 03:41 am, Doc Shipley wrote:
ISTR somebody recently mentioned soldering battery
leads to two legs
of a Dallas CMOS clock chip. Does that ring any bells?
I'm fiddling with a Compaq SLT/286 whose Dallas module is very dead.
I'd like to fix it.
Speaking of which, I have one of those modules that I pulled off some board
that was otherwise trashed. Is there any easy way to tell what condition the
battery is in?
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, a critter that can
be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
4:27 p.m.
Did some digging--apparently you can use a DS12887 as a direct
replacement--and they're available new. See:
http://www.pro-networks.org/forum/post-183844.html&sid=0413dac1eb5667f5…
cd2a7812723
3:47 p.m.
On Thursday 29 December 2005 03:41 am, Doc Shipley wrote:
ISTR somebody recently mentioned soldering battery
leads to two legs
of a Dallas CMOS clock chip. Does that ring any bells?
I'm fiddling with a Compaq SLT/286 whose Dallas module is very dead.
I'd like to fix it.
Oh, and I _was_ able to find the datasheet for the one I have on hand here,
maybe that's worth a shot? Don't remember where I found it offhand, though
alldatasheet.com is probably a good place to start.
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, a critter that can
be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
5:58 p.m.
On Thu, 29 Dec 2005 02:41:22 -0600
Doc Shipley <doc at mdrconsult.com> wrote:
ISTR somebody recently mentioned soldering battery
leads to two legs
of a Dallas CMOS clock chip. Does that ring any bells?
The method for installing a battery on a Sun NVRAM module is well
established and can be searched. I've done that one on numerous
occasions. I think the Dallas chips are laid out entirely
differently. Probably someone should dissect one with a dremel
tool and write a howto somewhere. It is a worthwhile project.
The upper module is almost certainly sealed seperate from the
chip itself, if it's like the Sun-type modules, there are
contacts somewhere you can dremel in to and solder on an external
battery lead.
I have a pile of 'old' Pentium II and Pentium III motherboards in
a box just waiting for me to desolder and save the Lithium
battery sockets from. I plan to epoxy them on any further Sun
NVRAM modules I 'upgrade' (and there are quite a few here that
still need that)
6:18 p.m.
On 12/29/2005 at 5:58 PM Scott Stevens wrote:
The method for installing a battery on a Sun NVRAM
module is well
established and can be searched. I've done that one on numerous
occasions. I think the Dallas chips are laid out entirely
differently. Probably someone should dissect one with a dremel
tool and write a howto somewhere. It is a worthwhile project.
The upper module is almost certainly sealed seperate from the
chip itself, if it's like the Sun-type modules, there are
contacts somewhere you can dremel in to and solder on an external
battery lead.
I can see where digging into the clock chip for a Sun might be worthwhile
as replacements are hard to come by, but the DS1287 used in the Compaq (and
a lot of PCs) is relatively inexpensive and readily available. It's robably
not worth the trouble digging into the EDIP to find where to hook the
battery up.
If an external battery is desired, you could just take a DS1285, which is
essentially the 1287 without the battery and hook a coin cell between pin
20 and ground.
Cheers,
Chuck
6:31 p.m.
On Thu, 29 Dec 2005 15:18:32 -0800
"Chuck Guzis" <cclist at sydex.com> wrote:
On 12/29/2005 at 5:58 PM Scott Stevens wrote:
Some of us are just more stubborn and cheap (and whatnot else)
than others. I like solutions that I know I will be able to use
for the next 25 years. I don't know how long Dallas will
continue to make the DS1285. And I have encountered motherboards
where the CMOS module is SOLDERED ON THE MOTHERBOARD (*yikes*).
The method for installing a battery on a Sun NVRAM
module is well
established and can be searched. I've done that one on numerous
occasions. I think the Dallas chips are laid out entirely
differently. Probably someone should dissect one with a dremel
tool and write a howto somewhere. It is a worthwhile project.
The upper module is almost certainly sealed seperate from the
chip itself, if it's like the Sun-type modules, there are
contacts somewhere you can dremel in to and solder on an external
battery lead.
I can see where digging into the clock chip for a Sun might be worthwhile
as replacements are hard to come by, but the DS1287 used in the Compaq (and
a lot of PCs) is relatively inexpensive and readily available. It's robably
not worth the trouble digging into the EDIP to find where to hook the
battery up.
If an external battery is desired, you could just take
a DS1285, which is
essentially the 1287 without the battery and hook a coin cell between pin
20 and ground.
That makes sense. Ideally the original module belongs 'tied with
string in a cloth bag within the housing' as was discussed here
awhile back, to preserve the authenticity of the original system.
10:07 p.m.
On 12/29/2005 at 6:31 PM Scott Stevens wrote:
Some of us are just more stubborn and cheap (and
whatnot else)
than others. I like solutions that I know I will be able to use
for the next 25 years. I don't know how long Dallas will
continue to make the DS1285. And I have encountered motherboards
where the CMOS module is SOLDERED ON THE MOTHERBOARD (*yikes*).
Scott, the Compaq SLT 286 is one of those. :) (and of course, on modern
mobos, the CMOS and clock is buried somewhere on a corner of one of the
support chips, which is soldered in).
If you're really bored, you can try digging into a DS1287, like this guy:
http://perso.wanadoo.fr/dsavel/ds1287e.htm
Suprise, suprise, he found a 1285 inside!
Another alternative is to use an MC 146818A and external battery and
resonator.
Cheers,
Chuck
6:39 p.m.
Chuck Guzis wrote:
On 12/29/2005 at 5:58 PM Scott Stevens wrote:
Except the DS1285 is nearly as expensive as a DS12887.... I picked
up a DS12887 from Maxim (nee Dallas) for $6 + S&H.
Thanks for the pointers, y'all. I don't really collect PCs, but that
SLT/286 has some sentimental significance. It's worth a couple of bucks
and some solder time.
ObFunny:
When I was looking around at prices, I did find a site selling DS1287
modules. *Used* DS1287 modules.
Doc
The method for installing a battery on a Sun NVRAM
module is well
established and can be searched. I've done that one on numerous
occasions. I think the Dallas chips are laid out entirely
differently. Probably someone should dissect one with a dremel
tool and write a howto somewhere. It is a worthwhile project.
The upper module is almost certainly sealed seperate from the
chip itself, if it's like the Sun-type modules, there are
contacts somewhere you can dremel in to and solder on an external
battery lead.
I can see where digging into the clock chip for a Sun might be worthwhile
as replacements are hard to come by, but the DS1287 used in the Compaq (and
a lot of PCs) is relatively inexpensive and readily available. It's robably
not worth the trouble digging into the EDIP to find where to hook the
battery up.
If an external battery is desired, you could just take a DS1285, which is
essentially the 1287 without the battery and hook a coin cell between pin
20 and ground. 
30 Dec
30 Dec
7:18 a.m.
On 12/29/05, Doc Shipley <doc at mdrconsult.com> wrote:
Thanks for the pointers, y'all. I don't
really collect PCs, but that
SLT/286 has some sentimental significance. It's worth a couple of bucks
and some solder time.
I removed (desoldered) a dead Dallas clock module from mine and
installed a low-profile socket only to find that there isn't even
clearance for _that_. So I nibbled a hole in the bottom of the
battery tray, and the replacement module sticks up just a little bit.
(for those that might not remember previous Dallas threads, I use my
SLT/286 w/docking station to run my UP600a device programmer).
-ethan
7:44 a.m.
Ethan Dicks wrote:
On 12/29/05, Doc Shipley <doc at mdrconsult.com>
wrote:
Hmmm. I know it's near-heresy here, but I'll probably just solder
the new clock chip back in. Unless you'd know the part number of said
low-profile socket? ;)
Thanks for the pointers, y'all. I
don't really collect PCs, but that
SLT/286 has some sentimental significance. It's worth a couple of bucks
and some solder time.
I removed (desoldered) a dead Dallas clock module from mine and
installed a low-profile socket only to find that there isn't even
clearance for _that_. So I nibbled a hole in the bottom of the
battery tray, and the replacement module sticks up just a little bit. (for those that might not remember previous Dallas
threads, I use my
SLT/286 w/docking station to run my UP600a device programmer).
I found the setup disk, but I still haven't figured out - does this
model have the Compaq setup partition on the drive? If so, how do I set
that up?
I'm also trying to figure out how a 2" IDE cable can go south. It
did, though. I have 2 drives that the setup can see fine with another
cable, but the short one is toes-up.
Doc
10:03 a.m.
On 12/30/05, Doc Shipley <doc at mdrconsult.com> wrote:
Hmmm. I know it's near-heresy here, but
I'll probably just solder
the new clock chip back in. Unless you'd know the part number of said
low-profile socket? ;)
Dunno about part numbers - I just had one in my stash.
I found the setup disk, but I still haven't
figured out - does this
model have the Compaq setup partition on the drive? If so, how do I set
that up?
Hmm... dunno about a partion (for this model - later models _do_ have
one), but ISTR finding the relevant setup disks online to do it from
floppy after a google search.
I'm also trying to figure out how a 2" IDE
cable can go south. It
did, though. I have 2 drives that the setup can see fine with another
cable, but the short one is toes-up.
Odd... well... those cables probably weren't designed for lots of
fiddling/remounting, etc.
-ethan
10:12 a.m.
On Fri, 30 Dec 2005 06:44:58 -0600
Doc Shipley <doc at mdrconsult.com> wrote:
Ethan Dicks wrote:
Naw, adding a socket amounts to 'modifying the design' and
ruining the historical value of the piece. You'd be doing it
just for 'convenience' which would be the same as replacing
special proprietary screw heads on a power supply. ;-)
On 12/29/05, Doc Shipley <doc at
mdrconsult.com> wrote:
Hmmm. I know it's near-heresy here, but I'll probably just solder
the new clock chip back in. Unless you'd know the part number of said
low-profile socket? ;)
Thanks for the pointers, y'all. I
don't really collect PCs, but that
SLT/286 has some sentimental significance. It's worth a couple of bucks
and some solder time.
I removed (desoldered) a dead Dallas clock module from mine and
installed a low-profile socket only to find that there isn't even
clearance for _that_. So I nibbled a hole in the bottom of the
battery tray, and the replacement module sticks up just a little bit. 
11 a.m.
Rumor has it that Doc Shipley may have mentioned these words:
I'm also trying to figure out how a 2" IDE
cable can go south. It did,
though. I have 2 drives that the setup can see fine with another cable,
but the short one is toes-up.
Short "flexi-things" generally don't flex nearly so well as long
"flexi-things."
I've seen lots of short cables "cross to the other side" in my day.
Laterz,
Roger "Merch" Merchberger
--
Roger "Merch" Merchberger | "Bugs of a feather flock together."
sysadmin, Iceberg Computers | Russell Nelson
zmerch at 30below.com |
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