SOME power to MB, but nothing else

[jackj]

I was having boot up issues; figured it was virus/malware-based, and ultimately pulled the hd to slave it elsewhere and do clean install. Upon putting it back in, I get a green light on the MB, next to CPU fan, but nothing else happens. I tested the PS with a PS tester, and all connections seem to be getting proper power. Doing this also means I checked the connections to the MB from the PS. Outside of a poor grounding (and nothing should have changed since I pulled the hd), would it have to be a MB (capacitor, etc.) gone bad problem? Am I right that if it were RAM that fans would spin and it would try to post, but just wouldn't? Thanks!

[mechbas]

System board go bad for a variety of reasons. If this is an old board how old is the bios batt.?
"Am I right that if it were RAM that fans would spin and it would try to post, but just wouldn't? Thanks! " Maybe maybe not. Not posting is a serious board issue that may or may not signal a system board issue. If NONE of the fans are spinning then there IS a PSU problem. The fans run on 12v. if memory serves.

[jackj]

System board go bad for a variety of reasons. If this is an old board how old is the bios batt.?
"Am I right that if it were RAM that fans would spin and it would try to post, but just wouldn't? Thanks! " Maybe maybe not. Not posting is a serious board issue that may or may not signal a system board issue. If NONE of the fans are spinning then there IS a PSU problem. The fans run on 12v. if memory serves.

Thanks for the reply, but if it were the ram, wouldn't the fans spin? Not sure about the cmos battery, but wouldn't that simply not retain the cmos info, and again the fans would spin?
The cpu fan gets its power via the MB, so couldn't the PSU be fine and be delivering the power to the MB, but it doesn't get relayed on, either bec. of capacitor, grounding, or something else to do with the MB? The PSU fan doesn't turn on, but it only would when power is being drawn. When I use the tester on the MB the PSU fan does turn on.
I just re-tested the PSU and it seems fine (does the 4 pin only put out 12v?) I also tried another PSU, that again seemed to test fine, but it was lying around so can't confirm its condition. Same results. I was wondering if it were the power button on the front of the case, but I bridged the two pin connector on the MB, that connects to that switch, and nothing. That should turn it on, shouldn't it? Thanks again for any help.

[caperjack]

I was having boot up issues;

what kind of issues ,what error message if any were you getting ?

all you did was remove/replace the hard drive ,correct !so disconnect the power to the hd,and try turning it on ,with out it connected to the harddrive .

[jackj]

what kind of issues ,what error message if any were you getting ?

all you did was remove/replace the hard drive ,correct !so disconnect the power to the hd,and try turning it on ,with out it connected to the harddrive .

The boot-up issues prior to slaving the hd was it would go to black screen before getting to Windows logo. Couldn't get into safe mode. No beeps. I tried fixboot & fixmbr, with no success. Was going to try re-install with rescue disk (old emachines computer with that type of disc as opposed to a system disc), but didn't want to risk loss of data, so took out hd to slave it to another machine. Put it back in to reinstall and that's when this happened.

With or without hd, same symptoms since it never even gets to that point.
When I plug in the power supply, a green light shows on the MB. Upon pressing the power button, nothing happens. No PSU fan; nothing. I tried jumping the two pin connector on the MB, that leads to the front case power button; still nothing.
I tested the PSU with a tester, and it said it was fine (green lights for the 12v & 5v, for the 20 pin, 4 pin and molex.
I tried a different PSU, that also tested fine (though it hadn't been in a system recently), with same results.

[caperjack]

i was working a older machine recently and the motherboard died while i was working on it ,quite simply this things happen !

[mechbas]

"Thanks for the reply, but if it were the ram, wouldn't the fans spin?"
No, RAM and fans are on a different power circuit.
"Not sure about the cmos battery, but wouldn't that simply not retain the cmos info, and again the fans would spin?"
If the cmos battery were dead then the cmos(bios) support that ALL devices require would be invalid. The actual devices (RAM, disk/disc drives, etc.) goes down a device heirarchy, the least critical goes away first. The fans are NOT dependent on the cmos for support.
"The cpu fan gets its power via the MB, so couldn't the PSU be fine and be delivering the power to the MB, but it doesn't get relayed on, either bec. of capacitor, grounding, or something else to do with the MB?"
Possibly, yes.
"The PSU fan doesn't turn on, but it only would when power is being drawn. When I use the tester on the MB the PSU fan does turn on."
The PSU (internal) fan is supposed to be on ALL of the time that the system is under main power from the PSU. Same goes for the CPU cooler fan.
"I just re-tested the PSU and it seems fine (does the 4 pin only put out 12v?) I also tried another PSU, that again seemed to test fine, but it was lying around so can't confirm its condition. Same results."
The 12v. main power connector may give you 12v. DC but not AC which some components on that circuit may well depend.
"I was wondering if it were the power button on the front of the case, but I bridged the two pin connector on the MB, that connects to that switch, and nothing. That should turn it on, shouldn't it?"
Basically yes. The power on system board connector is a momentary switch which may, but probably not, be dependent on the bios for support. Best determination here is a defective board.
When the first personal home computers came out it was possible for an electronic tech to actually repair the system board and return it to use the same way that most TVs are done now. As the technology got more sophisticated that option went out the window. It's far less expensive and less trouble to simply replace the board. As an example, the component (system) board, to which you refer, was only one circuit board. Today, the component (system) board may have three or more layers.

[jackj]

Yeah, that's what I was figuring. I was just mainly trying to confirm that:
a) even if ram was bad, the PSU fan should still power up and it should try to POST
b) That jumping the 2 pins on the MB should start it the same as pushing the button on the front of the case would
And thanks for confirming that the cmos battery wouldn't affect the PSU fan spinning or not. Must be the board. Yeah, I read up on and one time was going to try to replace a cap on a board, but with the multi-layers, SO sensitive (and I'm not exactly experienced in soldering, either!) Newegg, here I come... :) Thanks again for the help.