Post by PaulPost by James D. AndrewsPost by KHLPaul, Baron
Thanks for the info, the last Link I think is the ticket (hoping) ..
That is a great site, http://www.hardwaresecrets.com/article/81/3
My next trick is the surgery.
I'm still wondering, if the battery is dead, will it boot, as in
give me something to the monitor..?
The appnote from the Maxim link does not say this specifically.
Thanks Again Ken
Post by BaronPost by KHLOld machine, clean, 13 years old, "NO VIDEO signal", ran flawlessly
for 13 years.
"ERROR BEEPS at post ", Beep Beep,(pause) Beep Boop !
Can not find this audio code anywhere,
Found statements like, "too many different machine,each may have
different codes."
AWARD bios, INTEVA machine 1996, swapped video cards, memory swaps.
Pwr Sup chk, no success.
Could the ODIN CMOS chip, if the internal BATTERY were dead,
prevent the machine from booting?
(FYI and Dallas Semi says, battery life 5~10 years,)
Any info would be appreciated.
Thanks Ken.................
PS. Old machines that still do a job are hard to give up.
If I recall, Phoenix Bios, battery failure. Can't find my BIOS book to
confirm it. On some machines you can plug in an external battery.
Often 4 AA cells or 6volt Lithium battery. Assuming you can still find
one.
You can use an archived copy of the bioscentral.com site, to look
for beep codes. Don't use the current site - the browser marked
it as a known "attack" site, so the current site is not safe.
The archive should be OK.
http://web.archive.org/web/20060314035442/www.bioscentral.com/beepcodes/awar
Post by PaulPost by James D. AndrewsPost by KHLdbeep.htm
( Warning -- http://www.siteadvisor.com/sites/bioscentral.com )
*******
This isn't a real data sheet, but is as close as I could get.
http://web.archive.org/web/19980610044002/http://www.dalsemi.com/DocControl/
Post by PaulPost by James D. AndrewsPost by KHLPDFs/12887a.pdf
http://www.qxsz.com/images/time/12c887.gif
(Dallas is now a part of Maxim.)
http://www.maxim-ic.com/appnotes.cfm/appnote_number/503
http://www.epower2go.biz/index1.html
http://www.hardwaresecrets.com/article/81/3
Someone even makes a board, to write stuff into the RTC.
Presumably, for those cases, where the RTC cannot be erased,
or the BIOS won't program it. This thing is old enough, it is
still an ISA board.
http://www.costronic.com/Ev656.htm
Good luck,
Paul
Maybe a stupid question on my part or a blaring overlook of something, but
can't you just replace the battery? A lot of problems with my older systems
were solved with a couple bucks and a trip to Wally World.
What am I missing here?
Woof
The Dallas chips, have the battery hidden inside the plastic.
Which is a stupid move, but does make manufacturing easier.
(The component is probably safe to wash with flux remover.)
I've seen one person, Dremel the plastic off one of those
chips, and fit batteries to it, but the result was just
a mess. It helps if you know the internal layout, so you
don't Dremel the wrong thing (like cut a conductor).
The batteries are what makes this component, taller than normal.
The IC is in the bottom half, the batteries above. There might
even be a 32KHz quartz crystal in there as well.
http://sales.jack.ch/images/DSC00605_Dallas_DS12887_RTC.JPG
What I don't understand, is if +5V is available on the board,
the Dallas chip has a +5V input as well as the battery internally.
You'd think, via diode ORing, that the motherboard power supply
would power the Dallas, even if the BIOS settings and time
were corrupted. So as far as I can see, the BIOS should still
start. The issue would be, whether the BIOS has the modern
startup logic in it, to compute the checksum of the CMOS
RAM locations (114 bytes?), and overwrite them to default values
if the checksum indicates corruption.
The difference on a modern motherboard, where it stops booting
when the battery is dead, is on the modern motherboard, the
CMOS battery actually powers a small portion of the Southbridge
"well". Everything in the well is supposed to be isolated
with transmission gates, so there shouldn't be phantom current
flow and the like. And yet, there are persistent reports, that
on some motherboards, a flat battery prevents booting. And that
suggests that other portions of the Southbridge, or perhaps
some power management logic, is being compromised by the flat
battery.
In the case of the Dallas, it is a separate subsystem, and has a
byte wide parallel bus connected to some other component on the
motherboard. It doesn't get its fingers into any power management
logic. Depending on whether the outputs are failsafe or not,
I suppose it could clamp the bus it's on, to ground. But I don't even
know the name of the bus a thing like that sits on, in an older
PC architecture. (Would they put that on the ISA bus ?)
Paul
Paul,
My reasoning all started from my HP 6653C , the battery died,
nothing ,no boot. Changed the battery, ran a scan disk, OK....
Your last description of the boot process complements other
explanations I've read, that made me aware for differing/
variations in the bios/boot sequence. Traced many runs on the Pcb
the +5V pin 24 connection goes right to the Pwr Sup +5.
The description of operation specks of biasing at Pwr down,
dropping below 4.25V and then to 3V, my thoughts were
to a DELAY at Pwr up if the battery was dead.
That is why I ask and research the "NO VIDEO" at boot,
the fans spin up, HDD winds up, this is more than the
HP did when its battery died.
The HP is from 2000, many changes in 4years..
At present collecting tools and thoughts to remove the top
of the RTC. It is positioned between the ISA and PCI slots,
next to the bios and a few jumpers on both sides. Like it's
being protected from hands such as mine.
WITH CARE, will be the theme...
A thought, if I added INTEVA to my original post, possible a tech
with "hands on" might respond, they had a shop/show room 5 miles
from me years ago.(Pipersville Pa)...
Thank Again, Ken
