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Tyan Thunder K7 issue?
kellyclan Sep-05-01 03:14 AM
okay, the hardware:

-Tyan Thunder K7 mobo, BIOS 2.06(a, i believe) heatsink on the N. Bridge
-1.2ghz AthlonMP x2 w/ approved Coolermaster EP5-6I11 HSFs
-Approved Delta PSU
-3 approved 80mm fans, one front, two back

i have been getting spontaneous shutdowns, much like the plug was simply pulled from the wall. Case open, closed, different combos of fans, no difference. Seems to be totally random. 5 minutes. 2 hours. But always, always if i shut down, then go to start back up. Starts to hum up, then quits on me.

Goal is to dual boot WinME/Win2kPro, so its only got ME on it right now. Device manager reports the PCI Bridge as exclaimed, but other than that, no obvious/unfixable OS issues.

i've been told its likely the PSU, so before i send it back, i'm soliciting opinions since i haven't been able to find a place that can test it for me yet.


1. RE: Tyan Thunder K7 issue?
lbyard Sep-05-01 04:52 AM
In response to message 0
In my experience this kind problem is usually not caused by a bad power supply. It is usually caused by a short circuit. The two most common types of shorts in home-built computers are a loose screw of under the motherboard or a standoff under the motherboard where there is no motherboard mounting hole. Less frequent shorts are caused by pushed-in pins on the 5 1/4” drive power connectors and flat drive cables that have become frayed. Depending on the motherboard, CPU overheating and cock-eyed expansion boards can have this symptom. Another thing that can cause a shutdown after a period of time is a motherboard heat related problem and is usually caused by an extremely fine crack in the motherboard. Lastly, the power supply could indeed be defective. The thing that fails most often in a power supply is the fan motor bearing. Try it in another computer. Check the power cord. Larry

2. RE: Tyan Thunder K7 issue?
kellyclan Sep-05-01 07:32 AM
In response to message 1
Thanks for the tips.

i went through and triple-checked, all mounting holes equal mounting points/screws. All the drive cables seem to be viable. Expansion boards, its been misbehaving since before the soundcard and RAID controller were put in(only two cards on there now). As i haven't been able to get it to flash to the upgraded BIOS with the overheat warning beep feature, i have no way to tell at the moment if the CPUs are overheating. The HSFs are about 100*F by feel, and they're nothing fancy, took them right off the AMD-approved list. Going to try replacing the stock thermal pads with silver, see if that makes a difference.

Is there any way i can check for a motherboard crack, or is that just an assumed ailment once everything else is eliminated, to be confirmed by manufacturer?

Haven't been able to find anyplace to test it out yet, since it takes an oddball 12-pin connector. Going to keep looking. Thanks again!

3. RE: Tyan Thunder K7 issue?
lbyard Sep-05-01 04:10 PM
In response to message 2
>Going to try replacing the
>stock thermal pads with silver,
>see if that makes a

I strongly doubt that it will solve the problem.

>Is there any way i can
>check for a motherboard crack...

I use a large, illuminated magnifying glass mounted to my workbench. It is unlikely that you will find it. If the motherboard was warped when you bought it, then that is a clue. Other things can cause the problem and they might be easier to see.

I would pull the board and remount it. That sometimes fixes “mystery” problems.

I would test the board in the minimal bootable configuration. See http://duxcw.com/faq/mb/mb.htm. Larry

4. RE: Tyan Thunder K7 issue?
kellyclan Sep-06-01 08:56 PM
In response to message 3
Just wanted to letcha know, it seems to be working!

i did what you suggested, pulled out the soundcard and RAID controller, unhooked the whole thing and pulled out the mobo. Since they were already messy anyways, i did clean off the thermal goo and apply a coat of silver on one of the CPU/HSFs and installed that.

Plugged in one of my 256mb RAMs and the HDD and powered it up. Running on 3hrs now and none of the shutting down or powering up issues thus far.

So now i'm going to add the RAM sticks one at a time, then wire in the floppy and DVD, then go to the soundcard and RAID, then if that all pans out, add the second CPU.

Its all just sitting on its box on the side of the big beautiful case i got, but, by god, it works! It's alive! Muahahaha! It's ALIVE! Heh.

Thanks a mil!

5. RE: Tyan Thunder K7 issue?
kellyclan Sep-07-01 06:11 AM
In response to message 4
LAST EDITED ON Sep-07-01 AT 06:12 AM (GMT)

Well, the issue seems to be in at least two places.

--If the mobo is mounted in the case with the 3 screws that curve around the bottom righthand corner in place, it craps out.

--If i plug in the power to one or both of the 40gb HDDs i plan on using in the RAID array, it craps out. Same symptoms.

It *works* in this config:
-mobo totally out of case or mounted with screws only along the top and rear of the board
-One to four DIMMs
-floppy drive
-30gb HDD
-Two 80mm exhaust fans out the rear
-No PCI/AGP cards installed (onboard video)
-Haven't attempted 2nd CPU, CD drives or case fan yet

The one CPU in there now runs at 39-42C according to BIOS, so i think that rules out overheat. i swapped the IDE power connectors around, so a bad connector seems unlikely.

The power readings at the bottom do bounce around, i don't know if that would indicate a short or lack of power? +12 reads a steady 12.34 but the -12 bounces between ranges of 12.23xx and 12.31xx. This mean anything?

7. RE: Tyan Thunder K7 issue?
lbyard Sep-07-01 08:02 AM
In response to message 5
>the mobo is mounted in
>the case with the 3
Not enough screws. And you had better not have a stand-off without a screw in it touching the back of the motherboard where there is a mounting hole (= intermittent ground = system crash or rebooting itself, etc.), and, worse, where there is no mounting hole ( = smoke).

>that curve around the
>bottom righthand corner in place,

I don’t understand your description. If the screws are not grounding properly (not making good contact, loose, cock-eyed…) or the heads of the screws are covering printed circuit traces, there could be problems. Do not over-torque screws.

>--If i plug in the power
>to one or both of
>the 40gb HDDs i plan
>on using in the RAID
>array, it craps out. Same

Check the connectors for pushed-in pins. The extra load caused by the drives could pulling a power supply down, which may already have too large a load on it from another problem, to the point that the system crashes.

What case and power supply are you attempting to use?

>The one CPU in there now
>runs at 39-42C according to
>BIOS, so i think that
>rules out overheat. i swapped
>the IDE power connectors around,
>so a bad connector seems


>The power readings at the bottom
>do bounce around, i don't
>know if that would indicate
>a short or lack of
>power? +12 reads a steady
>12.34 but the -12 bounces
>between ranges of 12.23xx and
>12.31xx. This mean anything?

Yes: they are normal. The +-12 volt power is not regulated like the other voltages. They are for drive motors, fans, and serial I/O, which are much more tolerant than the CPU, memory, etc.

You probably have a motherboard mounting/grounding problem and/or a noisy/defective/inadequate power supply. Or something I can’t see because I ain’t there.


8. RE: Tyan Thunder K7 issue?
kellyclan Sep-10-01 02:38 AM
In response to message 7
The i just mentioned the screws cos it seemed by having them removed in one corner, things worked. Was wrong. There were still 11 screws holding the board in place, all in good, firm but not over tight.

In any matter, the thing doesn't work out of the case either. i was going to see if i could hook up all three HDD with the mobo out of the case. Can't imagine why its still whigging, it seemed to be working the other day when i had it out, hooked it up all in the same order per instructions.

Using a Delta DPS465AB(460w) and a Chenming 601-AE case, both recommended by the mobo manufacturer.
Connectors on the PSU are all in good shape. i'm pretty much at a loss here, nobody i've been able to find so far can check the board or the PSU for me, since the PSU is an oddball 24-pin type.

i really appreciate all the help you're giving. Gonna see what i can find about RMA's for the PSU and mobo. And maybe paint a target on the case.

9. RE: Tyan Thunder K7 issue?
gudlife Sep-20-01 00:29 AM
In response to message 8
As this thread continues, the PS is becoming more suspect...the K7s do draw a lot o juice and they are finicky. Some motherboards were better than others about having some capacitance built in to accomodate sudden demand, but others did not. Do you have another system or power supply lying around somewhere??? Be careful for obvious reasons, but I would try unhooking your case fans, leaving the system open and offloading the drives onto another PS just to test it.

Another issue that hasn't been brought up is your graphics card. What are you running? Some motherboards are plauged by not having enough juice to run some of these high draw AGP cards. Try just a generic PCI or ISA graphics card and see what happens.


10. RE: Tyan Thunder K7 issue?
gudlife Sep-20-01 00:30 AM
In response to message 9
Skip that last bit, just noticed that you are using the onboard controller...Ugh.


11. RE: Tyan Thunder K7 issue?
kellyclan Sep-20-01 09:33 AM
In response to message 10
Thanks for the replies. i returned the PSU, so when i get that back, we'll see what happens. i've also gotten my GeForce3 and a battery backup, so hopefully, i'll avoid any graphics issues now and the backup should keep a clean current flowing. Keep de fingers crossed for me.

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