Help, Call the Cavalry!

MichaelS wrote on 3/8/2006, 8:00 AM

I've got trouble!

I've removed my old power supply to try to upgrade my Gateway tower to a 400w PS. It didn't fit, so no connections were made.

I've reinstalled the old supply, made the connections and now...the monitors don't work. Everything seems to be getting power, but the screens remain black at bootup.

My video card is an ATI Radeon 9800. I have hooked power to the card, even swapping connectors.

Any suggestions? Thanks!

Back to post

Comments

Former user wrote on 3/8/2006, 11:54 AM

I might have missed this in a previous post -- but does your mobo have built-in vga graphics? Quite often if it does, it will revert back to the on-board vga chipset and ignore the slot mounted video card(s).

If it does have on-board vga then try plugging the monitor into the vga port on the mobo backplane and boot it up. If you see boot info then that is probably what's wrong. You'll need to dig into the CMOS settings to point to the aftermarket video card (PCI / AGP / PCI Express / etc)...

johnmeyer wrote on 3/8/2006, 11:56 AM

The on-board VGA is a VERY good idea to check.

The other thing is to plug the monitors into a known good computer, just in case something got glitched (unlikely, but it removes an unknown).

MichaelS wrote on 3/8/2006, 12:36 PM

I'm working without a schematic, but perhaps I've found something.

The regular device connector reads +5 & +12 normal.

The 4 pin connector from the power supply to the motherboard (the square one)...anyone have a clue as to what these voltages should be? I get strange readings when I put a meter to it.

The regular device connector reads +5 & +12 normal.

Former user wrote on 3/8/2006, 12:52 PM

The only way to accurately check a power supply is with a "power supply checker" (what a coincidence ;-).

This unit simulates the mobo connecter and snaps right into the PS / Mobo connector. I have one on my shelf. They are very inexpensive and can be purchased at most computer supply houses.

The reason you can't really reliably check a computer power supply with just a VOM is that most PS units have a line labeled "power okay". This line is connected to the mobo and confirms that there are no unusual loads present on the mobo and if everything is okay then it will signal the PS to apply full current to the outputs. The tester sets this signal bit as well as simulates a load on each of the PS connectors, which is critical for a switching power supply to work correctly.

MichaelS wrote on 3/8/2006, 1:08 PM

Thanks Jim. I discovered as much when I tried to check another power supply to compare voltages.

I'm getting a degree in this stuff today.

MichaelS wrote on 3/8/2006, 2:21 PM

Somebody strike up the marching band...we're gonna party tonight!

Finally got this thing licked. Out of shear desperation...given that I had unplugged and plugged everything else in the box umpteen times....I finally removed my 4 sticks of RAM. I reseated those babies back into their comfy little slots and ...Volia!...everything fired back up perfectly. Maybe it's just me, but I even notice a little more zip in my applications! Gateway had replaced my motherboard a few months ago following a power surge. I guess the tech did not reseat the RAM properly. It took just a lttle "jiggle" to create the problem.

I hope all of this will be of advantage to someone later. It's certainly been an education for me.

Thanks to everyone who took time out of their day to offer help. Even if it didn't solve the problem...I learned a few things and found out, as importantly, what the problem was not.

If I can get it by the wife (fat chance)...I'll call everyone over for a big celebration tonight! Thanks a million!

wolfbass wrote on 3/8/2006, 2:47 PM

Michael,

Is your wife's name 'Chance'?

If it is, I think you should be a little more respectful! :)

johnmeyer wrote on 3/8/2006, 4:30 PM

I wouldn't have suspected the RAM, partly because you didn't mention taking it out (and maybe you didn't actually take it out) but also because I wouldn't think that would totally kill the video (although if your card uses the MOBO memory, I guess it WOULD cause the display to die ... )

AlanC wrote on 3/9/2006, 1:30 AM

Jay,

"I think you meant to say cavalry."

The thread started as "Cavalry", somebody must have changed it. Can't imagine who :~)

JJKizak wrote on 3/9/2006, 5:28 AM

Small nudges fuel all of the repair industries.

JJK

Steve Mann wrote on 3/9/2006, 1:58 PM

"You should hear one beep during the boot cycle; if you hear multiple beeps, it probably means something is not seated properly"

It depends on the BIOS. I have one that beeps two times on normal startup and one long beep if there's a problem. The number of beeps is also a code to what is not working, again depends on which BIOS your MB is running.

Steve