Bios won't display; not power supply or video card problem

[Computer_Commando]

...The way it was originally set up, the 3-pin pump was plugged into the 4-pin "cpu_fan" slot, and the 4-pin radiator fan, was plugged into the 3-pin "pwr_fan" slot.  I don't really understand the choice.   As I said, I didn't originally install the cooler.  I have switched the connections, but that does not fix anything.

It was definitely connected improperly.  4-pin has speed control, 3-pin does not.
I was wrong before about which goes where.

I can see the cpu connector.  Can't see the others.
Data sheet says:
1 x CPU fan header
2 x system fan header
1 x power fan header

H/W Monitoring
1.  System voltage detection
2.  CPU/System temperature detection
3.  CPU/System/Power fan speed detection
4.  CPU overheating warning
5.  CPU/System/Power fan fail warning
6.  CPU/System fan speed control (Note 4)
(Note 4) Whether the CPU/system fan speed control function is supported will depend on the CPU/system cooler you install.

EDIT:  If you have any kind of 4-pin fan lying around, you can fool the system into turning on.  Remove the connection to the CPU fan header & just plug the fan in & lay it to the side.  Since the cpu heat exchanger & radiator seem to be transferring heat properly, but maybe not efficiently, this could show if it's only a fan problem.  If it gets to the BIOS, stop there & turn off.  Don't want it heating up too much.

Both have rpm sensing, so it could work reversed if the 3 is plugged into the 4 with the offset the right way.

[jeremysalwen]

Here are the pictures I took.  They show the overall view, the radiator+system fan, and the locations on the motherboard where I have connected the fan and pump.






I think I have done what you suggested (?)  I plugged the system fan into the CPU_FAN slot, and it runs fine (but it still doesn't show any further signs of booting).  and the system did work for two years with the 3-pin in the 4-pin slot and vice versa, I guess it just meant both fans were running at 100% the whole time.

[Computer_Commando]

The connectors should only insert one way, unless you force it.  See the plastic tab on the mobo connector?  It's keyed to a recess in the plug.  The cpu fan plug doesn't look right, it doesn't look keyed.  I can still see the header pins, where's the plug?  Follow the color codes on the pics above.  If inserted backwards, it won't work at all.  The power fan connector looks better, however I don't see a key slot (correction, I can barely make it out, after blowing up the pic).
<<I guess it just meant both fans were running at 100% the whole time.>> Correct.

[jeremysalwen]

Both fan connectors fit very nicely in without any forcing.  I reconnected the radiator fan to the CPU_FAN slot, and I double checked that it was going in the right way.  Looking at the plastic and the spacing of the holes, it was very obvious that there was no way it could fit in the other way.  The last picture from your previous post does not match the connectors I have.  The holes are offset from the center of the connector in mine, are square rather than round, and there are two plastic guides that stick out on the side that the connectors are closest to.  I will try to find a picture  I was interpreting the picture wrong, that seems to be the connector I have (although the one from the pump is a 3-pin fan)

[Computer_Commando]

Both fan connectors fit very nicely in without any forcing.  I reconnected the radiator fan to the CPU_FAN slot, and I double checked that it was going in the right way.  Looking at the plastic and the spacing of the holes, it was very obvious that there was no way it could fit in the other way.  The last picture from your previous post does not match the connectors I have.  The holes are offset from the center of the connector in mine, are square rather than round, and there are two plastic guides that stick out on the side that the connectors are closest to.  I will try to find a picture

[jeremysalwen]

yes that looks correct although the fins on the side of the connector are spaced further apart symmetrically (this is true of both connectors)

[Geek-9pm]

Why would a cooler failure cause this problem where the BIOS won't even load?  would it be through permanent damage to my CPU?

Is this a custom PC that had been working for several days? Weeks? If so, how would failure of the  cooling system stop the BIOS from starting?

[jeremysalwen]

I think I may have solved the problem.  I replaced my single RAM stick with my other RAM stick, and it booted!  I then tried back with the first stick and it works!  I put back the original power supply, it still works!   Removing the RAM causes exactly the same symptoms I had before.  I obviously have to test out all the other components, but this is tentative solution to my problem.  I am pretty sure that I wasn't pushing the RAM in all the way;  there are two clicks that it makes, and I stopped after the first one, and I had to keep pushing very hard to get the second and final click. 

Thank you everyone for your time and I'm sorry I wasted it on such a trivial issue.  I will certainly post back if any more issues arrive, but I'm tentatively marking it as solved.

p.s. should I keep the pump and radiator fan connectors swapped?

[jeremysalwen]

So I added my components back in one at a time, and everything is working now.  I'm pretty sure it was just that I wasn't clicking the memory down hard enough.

Also, I discovered that my front panel audio was not supposed to plug into the speakers that output the beep code on my motherboard, but instead another audio slot (I had forgotten where I unplugged the cable from). Both have pin patterns like this: , but I noticed when I turned on my computer the front headphone jack didn't work, and so it's possible that the motherboard was outputting beep codes, I just didn't have the front panel to hear them.  Thanks again for your time!

[Lisa_maree]

Hi

if you connected the speaker to the correct pins ie the block with the power switch, power led the speaker would have beeped 3 long 1 short which would have indicated a base memory failure.
It's interesting how many times this type of problem comes up and there is no speaker for post errors or post diagnostic card available.

A fan error or disconnected would cause an alarm on the above connected speaker with default bios settings.

So having a speaker available when assembling a computer can be very helpful



   

[Computer_Commando]

Glad that you got it solved.  You had me going for a while.  I've had some desktops where you almost had to use a vise to get the RAM seated.  Some RAM modules are probably thicker than the specifications allows, or the slots are thinner.

BTW, they used to put the BIOS speaker right on the motherboard, they seem to be getting away from that now.  Anything to save costs, let the case manufacturer worry about it.  If it was there, it looks like a short black cylinder with a hole in the middle.