Tyan Tiger S2725 won't boot anymore after CMOS clear

Hi, I have bought a S2725 board with two Xeon's and 4 Gb. To test it,
I connected it to a seasonic 350W psu. At startup it showed the post
messages, ram was ok, nothing wrong
and I could start system.
When I tried to enter BIOS it showed a password message, that I didn't
know of course.
So, shut down the thing, switched off psu and reset CMOS as it said in
the manual.
Then I started it up again but while the cpu fans started and power
led on, nothing happened after that (blank screen, no beeps). Any idea
what happened, anyone? Thnx a lot.

In article <efd1c959-9336-477f-9d4b->,
doozler <> wrote:
>Hi, I have bought a S2725 board with two Xeon's and 4 Gb. To test it,
>I connected it to a seasonic 350W psu. At startup it showed the post
>messages, ram was ok, nothing wrong
>and I could start system.
>When I tried to enter BIOS it showed a password message, that I didn't
>know of course.
>So, shut down the thing, switched off psu and reset CMOS as it said in
>the manual.
>Then I started it up again but while the cpu fans started and power
>led on, nothing happened after that (blank screen, no beeps). Any idea
>what happened, anyone? Thnx a lot.

Sounds like you need the replace the BIOS chip.
--
Member - Liberal International This is
Ici God, Queen and country! Beware Anti-Christ rising!
Never Satan President Republic!
12 May BC vote Liberal and remember the NDP scandals like Mulroney!

doozler wrote:
> Hi, I have bought a S2725 board with two Xeon's and 4 Gb. To test it,
> I connected it to a seasonic 350W psu. At startup it showed the post
> messages, ram was ok, nothing wrong
> and I could start system.
> When I tried to enter BIOS it showed a password message, that I didn't
> know of course.
> So, shut down the thing, switched off psu and reset CMOS as it said in
> the manual.
> Then I started it up again but while the cpu fans started and power
> led on, nothing happened after that (blank screen, no beeps). Any idea
> what happened, anyone? Thnx a lot.

Did you unplug the computer from the wall ? The important thing,
is that the +5VSB not be running. You can switch off the computer
at the back, but just for safety sake, unplugging the computer
guarantees no power is present. (One poster had a power supply,
where the switch was broken, and the supply was still powered,
even though the switch was set to "0".)

ftp://ftp.tyan.com/manuals/m_s2725_v100.pdf

ftp://ftp.tyan.com/img_mobo/i_s2725.tif

In either the manual, or the picture of the motherboard, you can see
the blue jumper to the right of the CR2032 CMOS battery. So that
is presumably the jumper you used.

If this is one of those motherboards, which can be damaged
by using the CMOS jumper, the most likely component to be
damaged, is located at 2 o'clock with respect to the
CMOS battery. If the clip of the battery holder was considered
to be at 12 o'click, there is a black thing with three pins on it,
next to the battery. That is most likely to be a dual diode with marking
of K45 on it. I have three motherboards that use the same diode
device, and for the same purpose. The CMOS power is maintained
through that black thing. In some cases, the damage is
severe enough, you can see burn marks on it.

BAS40W-05 (marking "K45" on top)
http://www.diodes.com/datasheets/ds30114.pdf

This is what the black thing with the three legs is responsible for.
This would be a typical circuit for it.

|
| anode common cathode
+5VSB ---- regulator ---- "3VSB" -------- diode ----+
| |
| +----> to CMOS/RTC
| | on Southbridge
CR2032 ---- 1Kohm resistor -------------- diode ----+
| anode
|
| <-- 3 legged dual diode -->

So the diode is a path that supplies power to the Southbridge well.
In an emergency, the tiny three-legged device can be replaced
with two silicon diodes. The silicon diodes will have a
higher forward drop, which means the battery may appear
to flake out sooner. But in many cases, the silicon diodes
may be the easiest to find locally.

http://www.radioshack.com/product/in...ductId=2062587

You can make a dual diode, out of a couple 1N4148's. You join the
"banded" ends of two diodes together. That forms the "common cathode"
lead, the center pin of the three legged device. The two loose
"non-banded" ends, become the anode connection, the two pins
on the other side of the device. Due to symmetry, it doesn't
matter which anode goes to which path. They're equal.

Naturally, you'd orient yourself with a multimeter set to volts,
and measure the voltage on the three legs, before assuming anything.
It could be there is nothing wrong with the K45. You'd expect to
see 3V - 0.4V drop or about 2.6V or so, on the common cathode
(middle) leg. If there was voltage present there, then the motherboard
should be able to start. With the motherboard powered and running,
you'd check the voltage again, to see if perhaps the problem
was insufficient voltage to maintain it in a running state.

If the middle leg isn't managing more than 2.0V, then I might
investigate the physical appearance of the K45. Apparently,
it fries pretty good when damaged, so you may be able to see
the damage. One poster told me, he could no longer read the label
printed on one of those, from the burn.

The soldering is delicate work, and I've made a mess of a couple
repairs. So someone pretty skilled at soldering, with a temperature
controlled soldering iron at the ready, would be needed to do the
repair. If you have a TV/radio repair shop nearby, consult them
as to whether they could do it for you. They might even have
a couple general purpose switching diodes in their parts
cabinet, to do the emergency repair.

Good luck,
Paul

Paul wrote:
> doozler wrote:
>> Hi, I have bought a S2725 board with two Xeon's and 4 Gb. To test it,
>> I connected it to a seasonic 350W psu. At startup it showed the post
>> messages, ram was ok, nothing wrong
>> and I could start system.
>> When I tried to enter BIOS it showed a password message, that I didn't
>> know of course.
>> So, shut down the thing, switched off psu and reset CMOS as it said in
>> the manual.
>> Then I started it up again but while the cpu fans started and power
>> led on, nothing happened after that (blank screen, no beeps). Any idea
>> what happened, anyone? Thnx a lot.

Another thing. Are you sure the jumper is currently in the
correct position ?

Paul

On May 1, 7:00*pm, Paul <nos...@needed.com> wrote:
> Paul wrote:
> > doozler wrote:
> >> Hi, I have bought a S2725 board with two Xeon's and 4 Gb. *To test it,
> >> I connected it to a seasonic 350W psu. At startup it showed the post
> >> messages, ram was ok, nothing wrong
> >> and I could start system.
> >> When I tried to enter BIOS it showed a password message, that I didn't
> >> know of course.
> >> So, shut down the thing, switched off psu and reset CMOS as it said in
> >> the manual.
> >> Then I started it up again but while the cpu fans started and power
> >> led on, nothing happened after that (blank screen, no beeps). Any idea
> >> what happened, anyone? Thnx a lot.
>
> Another thing. Are you sure the jumper is currently in the
> correct position ?
>
> * * Paul

Hi Paul,

I checked the D1 diode but it tested still ok. I followed the
instruction in the manual but I'm not sure anymore
if I unplugged the power adapters from the mb or not. At least the psu
was switched off. The jumper is in the correct position again.
Thanks for the explanation of the diode, I'll power it up again next
week and check voltages when "hot".

I can't think of any reason why a BIOS would become damaged from
removing cmos voltage momentarily?
Btw, my psu is 430w instead of 350w. Guess that's enough for a bare
board with no external devices attached except a hdd.

Albert

doozler wrote:
> On May 1, 7:00 pm, Paul <nos...@needed.com> wrote:
>> Paul wrote:
>>> doozler wrote:
>>>> Hi, I have bought a S2725 board with two Xeon's and 4 Gb. To test it,
>>>> I connected it to a seasonic 350W psu. At startup it showed the post
>>>> messages, ram was ok, nothing wrong
>>>> and I could start system.
>>>> When I tried to enter BIOS it showed a password message, that I didn't
>>>> know of course.
>>>> So, shut down the thing, switched off psu and reset CMOS as it said in
>>>> the manual.
>>>> Then I started it up again but while the cpu fans started and power
>>>> led on, nothing happened after that (blank screen, no beeps). Any idea
>>>> what happened, anyone? Thnx a lot.
>> Another thing. Are you sure the jumper is currently in the
>> correct position ?
>>
>> Paul
>
> Hi Paul,
>
> I checked the D1 diode but it tested still ok. I followed the
> instruction in the manual but I'm not sure anymore
> if I unplugged the power adapters from the mb or not. At least the psu
> was switched off. The jumper is in the correct position again.
> Thanks for the explanation of the diode, I'll power it up again next
> week and check voltages when "hot".
>
> I can't think of any reason why a BIOS would become damaged from
> removing cmos voltage momentarily?
> Btw, my psu is 430w instead of 350w. Guess that's enough for a bare
> board with no external devices attached except a hdd.
>
> Albert

The CMOS/RTC shouldn't have anything to do with the EEPROM
that holds the BIOS firmware. I don't see a reason for the
actual BIOS to be damaged. My theory is, that the processor
is not even trying to execute the BIOS at the moment.

If the Southbridge is not being powered, by the output of
that dual diode, that can be enough to prevent the motherboard
from starting.

If you want another experiment to try, power off completely
again, and pull all the RAM. See if the board will beep,
indicating a RAM error or not. If it will do that, then
some BIOS code got executed, and the processor did some
work. If you can get it to beep, then that is a good sign.
Then put back just one stick of RAM, and try again.

Paul

On May 2, 12:38*am, Paul <nos...@needed.com> wrote:
> doozler wrote:
> > On May 1, 7:00 pm, Paul <nos...@needed.com> wrote:
> >> Paul wrote:
> >>> doozler wrote:
> >>>> Hi, I have bought a S2725 board with two Xeon's and 4 Gb. *To testit,
> >>>> I connected it to a seasonic 350W psu. At startup it showed the post
> >>>> messages, ram was ok, nothing wrong
> >>>> and I could start system.
> >>>> When I tried to enter BIOS it showed a password message, that I didn't
> >>>> know of course.
> >>>> So, shut down the thing, switched off psu and reset CMOS as it said in
> >>>> the manual.
> >>>> Then I started it up again but while the cpu fans started and power
> >>>> led on, nothing happened after that (blank screen, no beeps). Any idea
> >>>> what happened, anyone? Thnx a lot.
> >> Another thing. Are you sure the jumper is currently in the
> >> correct position ?
>
> >> * * Paul
>
> > Hi Paul,
>
> > I checked the D1 diode but it tested still ok. I followed the
> > instruction in the manual but I'm not sure anymore
> > if I unplugged the power adapters from the mb or not. At least the psu
> > was switched off. The jumper is in the correct position again.
> > Thanks for the explanation of the diode, I'll power it up again next
> > week and check voltages when "hot".
>
> > I can't think of any reason why a BIOS would become damaged from
> > removing cmos voltage momentarily?
> > Btw, my psu is 430w instead of 350w. Guess that's enough for a bare
> > board with no external devices attached except a hdd.
>
> > Albert
>
> The CMOS/RTC shouldn't have anything to do with the EEPROM
> that holds the BIOS firmware. I don't see a reason for the
> actual BIOS to be damaged. My theory is, that the processor
> is not even trying to execute the BIOS at the moment.
>
> If the Southbridge is not being powered, by the output of
> that dual diode, that can be enough to prevent the motherboard
> from starting.
>
> If you want another experiment to try, power off completely
> again, and pull all the RAM. See if the board will beep,
> indicating a RAM error or not. If it will do that, then
> some BIOS code got executed, and the processor did some
> work. If you can get it to beep, then that is a good sign.
> Then put back just one stick of RAM, and try again.
>
> * * Paul

Paul,

I managed to get it started again
The things I did are these:

1) remove all memory and start up: 6 beeps indicating Missing Memory.
2) insert only bank 2 and 4: starts up normal and able to get to BIOS
setup with DEL key.
3) insert all memory: starts up normal now and able to get to BIOS
setup with DEL key.

I'm not sure why these steps were needed but I'm glad the thing works
now as expected.
Thanks for your help!

cheers Albert

doozler wrote:
> On May 2, 12:38 am, Paul <nos...@needed.com> wrote:
>> doozler wrote:
>>> On May 1, 7:00 pm, Paul <nos...@needed.com> wrote:
>>>> Paul wrote:
>>>>> doozler wrote:
>>>>>> Hi, I have bought a S2725 board with two Xeon's and 4 Gb. To test it,
>>>>>> I connected it to a seasonic 350W psu. At startup it showed the post
>>>>>> messages, ram was ok, nothing wrong
>>>>>> and I could start system.
>>>>>> When I tried to enter BIOS it showed a password message, that I didn't
>>>>>> know of course.
>>>>>> So, shut down the thing, switched off psu and reset CMOS as it said in
>>>>>> the manual.
>>>>>> Then I started it up again but while the cpu fans started and power
>>>>>> led on, nothing happened after that (blank screen, no beeps). Any idea
>>>>>> what happened, anyone? Thnx a lot.
>>>> Another thing. Are you sure the jumper is currently in the
>>>> correct position ?
>>>> Paul
>>> Hi Paul,
>>> I checked the D1 diode but it tested still ok. I followed the
>>> instruction in the manual but I'm not sure anymore
>>> if I unplugged the power adapters from the mb or not. At least the psu
>>> was switched off. The jumper is in the correct position again.
>>> Thanks for the explanation of the diode, I'll power it up again next
>>> week and check voltages when "hot".
>>> I can't think of any reason why a BIOS would become damaged from
>>> removing cmos voltage momentarily?
>>> Btw, my psu is 430w instead of 350w. Guess that's enough for a bare
>>> board with no external devices attached except a hdd.
>>> Albert
>> The CMOS/RTC shouldn't have anything to do with the EEPROM
>> that holds the BIOS firmware. I don't see a reason for the
>> actual BIOS to be damaged. My theory is, that the processor
>> is not even trying to execute the BIOS at the moment.
>>
>> If the Southbridge is not being powered, by the output of
>> that dual diode, that can be enough to prevent the motherboard
>> from starting.
>>
>> If you want another experiment to try, power off completely
>> again, and pull all the RAM. See if the board will beep,
>> indicating a RAM error or not. If it will do that, then
>> some BIOS code got executed, and the processor did some
>> work. If you can get it to beep, then that is a good sign.
>> Then put back just one stick of RAM, and try again.
>>
>> Paul
>
> Paul,
>
> I managed to get it started again
> The things I did are these:
>
> 1) remove all memory and start up: 6 beeps indicating Missing Memory.
> 2) insert only bank 2 and 4: starts up normal and able to get to BIOS
> setup with DEL key.
> 3) insert all memory: starts up normal now and able to get to BIOS
> setup with DEL key.
>
> I'm not sure why these steps were needed but I'm glad the thing works
> now as expected.
> Thanks for your help!
>
> cheers Albert

Strange things happens some times. Good job on the debugging!

Paul

On May 3, 7:52*pm, Paul <nos...@needed.com> wrote:
> doozler wrote:
> > On May 2, 12:38 am, Paul <nos...@needed.com> wrote:
> >> doozler wrote:
> >>> On May 1, 7:00 pm, Paul <nos...@needed.com> wrote:
> >>>> Paul wrote:
> >>>>> doozler wrote:
> >>>>>> Hi, I have bought a S2725 board with two Xeon's and 4 Gb. *To test it,
> >>>>>> I connected it to a seasonic 350W psu. At startup it showed the post
> >>>>>> messages, ram was ok, nothing wrong
> >>>>>> and I could start system.
> >>>>>> When I tried to enter BIOS it showed a password message, that I didn't
> >>>>>> know of course.
> >>>>>> So, shut down the thing, switched off psu and reset CMOS as it said in
> >>>>>> the manual.
> >>>>>> Then I started it up again but while the cpu fans started and power
> >>>>>> led on, nothing happened after that (blank screen, no beeps). Any idea
> >>>>>> what happened, anyone? Thnx a lot.
> >>>> Another thing. Are you sure the jumper is currently in the
> >>>> correct position ?
> >>>> * * Paul
> >>> Hi Paul,
> >>> I checked the D1 diode but it tested still ok. I followed the
> >>> instruction in the manual but I'm not sure anymore
> >>> if I unplugged the power adapters from the mb or not. At least the psu
> >>> was switched off. The jumper is in the correct position again.
> >>> Thanks for the explanation of the diode, I'll power it up again next
> >>> week and check voltages when "hot".
> >>> I can't think of any reason why a BIOS would become damaged from
> >>> removing cmos voltage momentarily?
> >>> Btw, my psu is 430w instead of 350w. Guess that's enough for a bare
> >>> board with no external devices attached except a hdd.
> >>> Albert
> >> The CMOS/RTC shouldn't have anything to do with the EEPROM
> >> that holds the BIOS firmware. I don't see a reason for the
> >> actual BIOS to be damaged. My theory is, that the processor
> >> is not even trying to execute the BIOS at the moment.
>
> >> If the Southbridge is not being powered, by the output of
> >> that dual diode, that can be enough to prevent the motherboard
> >> from starting.
>
> >> If you want another experiment to try, power off completely
> >> again, and pull all the RAM. See if the board will beep,
> >> indicating a RAM error or not. If it will do that, then
> >> some BIOS code got executed, and the processor did some
> >> work. If you can get it to beep, then that is a good sign.
> >> Then put back just one stick of RAM, and try again.
>
> >> * * Paul
>
> > Paul,
>
> > I managed to get it started again
> > The things I did are these:
>
> > 1) remove all memory and start up: 6 beeps indicating Missing Memory.
> > 2) insert only bank 2 and 4: starts up normal and able to get to BIOS
> > setup with DEL key.
> > 3) insert all memory: starts up normal now and able to get to BIOS
> > setup with DEL key.
>
> > I'm not sure why these steps were needed but I'm glad the thing works
> > now as expected.
> > Thanks for your help!
>
> > cheers Albert
>
> Strange things happens some times. Good job on the debugging!
>
> * * Paul

Found out one more thing:

After CMOS reset to default, the option Quick Boot was ENABLED ( =
( ?? ) According to the manual is should be off so that all (self-)
tests are executed at boot time. Due to this, among others the auto-
detect function doesn't work so that your attached drives are not seen
to be present for example, unless you are very lucky to have attached
it to the right connector. Maybe this is the reason why it didn't boot
when reset.
Setting the Quick Boot option to disabled, the thing performs booting
like one expects in the first place.

cheers Albert