HP IQ775-Asus A8SN-CF motherboard

[suiramix]

This is my first post and I am asking for some help regarding Asus A8SN-CF mobo part of HP IQ775 touchsmart desktop. This computer does power on, but no video on display, no BIOS splash, all fan running on high speed. Can be turn off by press and hold power button for more than 3 sec. I removed the power cord and hold the power button for 30sec to drain the system. As soon the power cord was plug-in the computer starts with same blank display.
The next step I removed the cover and I noticed on the motherboard 3 swollen capacitors- United Chemi-con KGZ-820uF/ 6.3V (near CPU and video card) and I did replaced only those one with new same capacity value …but same results.
Question: what is the easiest way to verify which is defective … do I have to replace all of them?
I am aware even I will change all capacitors still have the same problems !

[Uranium-235]

Re: HP IQ775-Asus A8SN-CF motherboard

you might be the victim of the nvidia 6100 northbridge solder going soft. reflow or reball

or it could be some of the other KZG's, sometimes they die without bloating

but most likely, its the nvidia chip

[mockingbird]

Re: HP IQ775-Asus A8SN-CF motherboard

This is one odd looking motherboard:

[Scenic]

Re: HP IQ775-Asus A8SN-CF motherboard

no wonder.. it's one of those odd all-in-one thingys..

http://www.ovi-online.com/bigpic/438...0703022223.jpg

to see if the board still has some life left in it, remove the RAM and power it up. it should start beeping at you about missing RAM..
if it's not even doing that, it doesn't look too good for this board :/

[suiramix]

Re: HP IQ775-Asus A8SN-CF motherboard

Hi guys
Thanks for advice , and yes I agree with you about weird shape and basically everything is odd: the power supply , power supply connector , the video card (MXM connector) and there is no room for air flowing.....reading other forums those HP touchsmart PC are notorious regarding video card Nvidia 7600 which require reflow (reball) ...
So I did remove the video card and RAM and unfortunately no change..no beeping...same thing it starts without pressing the power button...I will try to check the power supply voltages!?
Cheers!

[mockingbird]

Re: HP IQ775-Asus A8SN-CF motherboard

It's not just the videocard, it's the northbridge. I think the 6100 northbridges are the defective ones but better double check to make sure. 7100 I know for sure are defective.

[Uranium-235]

Re: HP IQ775-Asus A8SN-CF motherboard

^the point I was trying to make. if the chip isn't dead, try to reflow or reball it

[suiramix]

Re: HP IQ775-Asus A8SN-CF motherboard

Uranium and mockingbird are 100% right..the northbridge is failing due to high temp, poor airflow and useless thermal pads (like all those HP laptop DV6000-9000 series) ...and hard to believe even after I "succeed" to damage the motherboard (see "cap"photo), the computer is running after reflow-ing Nvidia 6100 !
Thanks guys for your help !

[Uranium-235]

Re: HP IQ775-Asus A8SN-CF motherboard

congrats! I prefer reballing cause 80% of reflows iv'e seen revert after a few weeks

but then again, i've never reaballed anything before, something I hope to start doing in a few weeks

[richrow2]

Re: HP IQ775-Asus A8SN-CF motherboard

This is my first post and I'm afraid it's going to sound stupid, but since I'm having the same problem with my IQ770, I need the help. What exactly do you mean when you say to "reflow or reball" the northbridge chip? And how do you check for this problem?

[somervillearron]

Re: HP IQ775-Asus A8SN-CF motherboard

hi could you help me please i am purchasing a broken one of these it is the vga but it power on ok and boots into windows because you can hear it i was wondeing can i use the screen for another computer if the worse happens i know it plugs into the board with them stupid plugs what i need to know is the name of the plugs and if i could get a converter to vga or i could put a cable on it i just havnt seen the pc yet and i was wondering if that would be possible to use the screen on my other pc
thanks and sorry i know this threads really old and also what do you think the chances are the board has the same problem as this guys?if so what and where should i look for the repair i can solder ok

[projekt1]

Re: HP IQ775-Asus A8SN-CF motherboard

Just came across this thread. From the looks of the last two posts I would'nt expect to get much help either but its worth a shot.

Problem: I have a IQ775, at startup the screen immediately turns on but just has horizontal lines and never changes from that, no boot screen or anything. I did a quick search and followed a disassembly video on YouTube. So I removed the video card but now I don't know whether it'is the card or the motherboard since reading this thread.

Question: Now that it has been torn down, how can I pinpoint the problem? Should I jusr replace the video card and hope for the best or not?

Thanks for the help.

Edit: Added some pictures for reference and maybe you experienced ones can tell whether if something looks good or bad.