Weirdness after replacing PSU

[TaoSan]

I have an Aspire X1200 whose power supply went out. I tried the paper clip trick, with no success, and so replaced it with a generic PSU (not a slimline PSU, so it has to sit outside the chassis, but it has the right connections and can power the whole system plus a little more).

The problem is, now when the new PSU is turned on, the CPU fan will run at its maximum speed, the drives will spin up, and the power light will come on (immediately; they don't wait for me to press the power button), but there's no POST and no monitor control. I've tried removing memory and peripherals, I borrowed a working PSU from another desktop, I redid the thermal grease on the CPU fan, and I checked the jumpers, all with the exact same result. This never happened with the original PSU. Any ideas?

 

[Harvey]

Hate to say it, but if the fans and drives spin up before the hitting start switch, but it doesn't post, it sounds like your CPU or your motherboard has some kind of problem.

 

[TaoSan]

UPDATE: I removed the battery from the motherboard and bridged the terminals for a moment. Now the fan won't run until the power switch is pressed, but I still have no POST and a racing CPU fan.

 

[Harvey]

If you added a separate video card, when you reset the BIOS, it may have defaulted to being set for the onboard video. If so, try removing the vid card and connecting to onboard video port. If that works, you can reset it, later.

Try removing all of the RAN and re-inserting just one stick. If that doesn't work, try as many other sticks as you have, one at a time. If you have other compatible RAM, try that, too.

If none of that works, I'd still suspect your motherboard or CPU.

Hope that helps.

 

[TaoSan]

Thanks, Harvey, but I've tried all that. Looks like your initial suspicion about the motherboard being blown is correct. Also, I found a blown cap in the power supply and the rectified is partially melted, so I'm gonna go with massive power surge.

*sigh* looks like it's time to go motherboard shopping.

 

[Harvey]

Thanks, Harvey, but I've tried all that. Looks like your initial suspicion about the motherboard being blown is correct. Also, I found a blown cap in the power supply and the rectified is partially melted, so I'm gonna go with massive power surge.

*sigh* looks like it's time to go motherboard shopping.

The specs for your Aspire X1200 and some other searching show that it uses a Socket AM2+ CPU and DDR2 RAM. If you're absolutely sure your CPU and RAM are good, Newegg has a couple of boards that may be able to use them for $40 and $45 plus shipping. I don't know anything about these boards so do your own homework.

If you're NOT absolutely sure the CPU and RAM are good, I'd recommend getting an entire new setup. You'll have newer gear, and you won't waste less time, and you won't have to worry about disappointment and lost money if the rescue attempt fails.

You can always test the CPU and RAM, later and either sell them or give them to a friend in need or build a second machine for yourself, a family member or a friend.

 

[TaoSan]

Well, I know that either this RAM is good or another two sticks in the massive pile 'o DDR2 in my lab is good (my sister gave me an HP pavilion tower that just beeps on startup. It also used DDR2, which I tried replacing. I'm swimming in the stuff.) The processor is a bit trickier. I used ESD-protected mats and wrist straps when handling all components, and I don't see any obvious damage to the CPU, so I think it's doing ok, but I don't know of any way to test a CPU without putting it into a working motherboard. Any idea how I could go about doing that?

 

[Harvey]

Well, I know that either this RAM is good or another two sticks in the massive pile 'o DDR2 in my lab is good (my sister gave me an HP pavilion tower that just beeps on startup. It also used DDR2, which I tried replacing. I'm swimming in the stuff.) The processor is a bit trickier. I used ESD-protected mats and wrist straps when handling all components, and I don't see any obvious damage to the CPU, so I think it's doing ok, but I don't know of any way to test a CPU without putting it into a working motherboard. Any idea how I could go about doing that?

A power surge could have killed your CPU. The only way to test it is in a known working motherboard. If you don't have one, it may be time to visit a local tech who has a test setup for the purpose.

The only problem with that is that a tech may charge you a good chunk of the cost of a new CPU for an already out of date formats, AM2+, rather than AM3 or 3+ and DDR2, rather than DDR3. That's why I suggested building a new setup and testing your current components later, once you've got a working rig.

 

[TaoSan]

UPDATE: So, I broke down and had the system bench-tested. Turns out that everything was good -- I just had a bent pin on my CPU. The computer is a little more frankenstein-esque (Due to the lack of a slimline PSU, I can't reinstall the DVD-RW without smashing into the CPU fan, so the DVR-RW and hard drive have to sit outside the unit, sans bezel), but it's working just fine. Next up, switching to a peltier coolant system to free up space!

 

[Meghan54]

Next up, switching to a peltier coolant system to free up space!

Seriously?

I'd spend the money on building a new system rather than spending it on an obsolete setup. You can recoup some of the cost of the new system by parting out your old stuff. That peltier setup is really just a waste of money on that old system of yours....the money would be better spent on upgrading, by far!