Solved Mobo failure?

[gregrocker]

Nothing on screen at all. Fans power up as well as power button light, but no LED on mobo (not sure there ever was).

Tried new monitor, Power Supply: same.

Removing RAM and everything else except CPU and onboard GPU chip generates no beeps.

It's an older HP Walmart special so no real value but want to use it as practice for trying everything possible to get it working.

 

[essenbe]

Sounds like it could be, Greg. With no ram the board should beep, a lot. To me that's a good indication there is a serious problem with the board.

 

[ICIT2LOL]

Hiyya Greg PSU? perhaps? try another mate nothing to lose.

Plus it could be just the 24 pin connection have a look around the base where it is soldered into the board any burn marks and chaeck the caps out too - blown tops ooze coming out etc.

No use just measuring the volts mate as they might be there but no current. Had one recently like that in my tester - just replaced the PSU and away it went.

 

[TVeblen]

Could be. Although there are some very cheap machines that do not give beep codes on errors. Or you need to connect a piezo speaker to the Speaker leads to get the beeps.

Always a good idea to check (use another) video cable.
And do a ClearCMOS.

 

[ICIT2LOL]

Hum I meant to say if you have a meter with the 24 pin plugged in try the power at USB headers for example or the soft on switch pins.

 

[gregrocker]

Thanks, hardware dudes!

Caps smooth. Tried another PSU, same. Pulled CMOS battery for an hour.

Interesting you mention USB because it had lost USB functionality and was rebooting to reinstall driver when it crapped out. Where are these USB headers you speak of, and how do I test them with multi-meter?

Also does onboard video chip (where?) have a cable?

Looking around for speaker without USB power now.

 

[ICIT2LOL]

Just use the black to a ground and touch each pin in turn some are just data but you know that I will have a look to see what config the pins are in but you should find some with power - should read up 5 volts.

Just found this http://www.directron.com/installusb.html

 

[ICIT2LOL]

Oh Greg I should have said to mate test test continuity of the ground pin to ground ( the resistance side).

 

[gregrocker]

How do I locate these pins you speak of on the mobo? General area?

I see the cable running to the front USB port which never really worked, but the rear ones are encased in alum. housing also on mobo.

Also what are these USB readings telling me?

 

[ICIT2LOL]

No mate they usually are on the edge of the board in line with the main power switch and HDD light connector block see pic they can be all sorts of colours just look for the ones that have nine pins to correspond to that plug with the nine sockets and one blanked off spot.

My board shot just happen to be sorting mine out

 

[gregrocker]

Found the 9 pin for the front USB ports which never worked. The one for the back is under aluminum housing I'd have to tear off. How do I use a multi-meter to test this exactly? I see no nearby ground.

 

[ICIT2LOL]

Any of the mobo fixing screws Greg they usually have a small circle of solder around them also - the pop rivet ends in the case sometimes have the bare metal showing but the screws are the best cos they ground the mobo to the case which is grounded via the PSU earth connection .

Usually it is one to the two pins at the opposite end to the blank.

You can test for ground between the ground pin and the screw and then the power using the screws for the ground to test that opposite pin (usually next to the ground pin) to see if there is power there - be careful to touch one at a time and not connect any two with the same probe

 

[gregrocker]

No power to those USB pins.

 

[ICIT2LOL]

No power to those USB pins.

Think Steve must have got it right mate the thing is cactus

Sorry mate if I were a little closer you could have a spare or two

 

[gregrocker]

It's OK Gary I had it taken off the E-recycle run so I could play with it some. Learned a little more.

Thanks to all. Wish I could rep you but you are such regulars for good hardware help I gotta pass more around.

 

[ICIT2LOL]

It's OK Gary I had it taken off the E-recycle run so I could play with it some. Learned a little more.

Thanks to all. Wish I could rep you but you are such regulars for good hardware help I gotta pass more around.

Yes Greg it is a shame you blokes cannot get access to old recyclers cos I have picked up quite a few that have really good hardware in them like the really nice 550 watt Coolermaster I stuck in the tester I told you about. I have also made up some good machines for those who cannot afford it from recycled stuff - I think the waste is criminal.

Now back to my recycled PSU for a bench tester woo hoo!

John