Replacement PSU shorted on old system. Is MB bad or should I just try another PSU?

jqpa

n00b
Joined
Mar 21, 2020
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3
I have an older system that died a while back and has been in storage for a while. I'm trying to get it running again now. When I was taking it apart, I accidentally pulled out the entire CPU along with the heatsink because they were fused together. I got them apart but a few CPU pins were bent. I straightened them out, put the CPU back in, and put new thermal paste to reattach the heatsink after I cleaned it.

I discovered the PSU was dead and dug out a used but seemingly working PSU someone had given me. It was only 20 pin, so I ordered a 20 to 24 pin adapter along with some additional matching RAM and a new video card. Everything arrived today and I set it up (except for DP-only video card since I don't have my DP monitor with me or a DP/HDMI adapter yet). The PSU powered up and one of the indicator leds on the MB came on, but there were no POST sounds or video and the CPU fan did not start. I don't think the case fans came on either. After maybe 30-60 second, the PSU loudly popped and shorted out.

I'm now trying to figure out what to do next and what to try replacing. I don't want to order a new PSU just to blow it out, but I also don't want to replace the MB and/or CPU if I don't have to. For reference, the MB is an ASUS M5A78L-M/USB3, the original PSU was a Seasonic SS-400FB, and the replacement that I just blew was an ULTRA ULT-600P. All of these components are at least 5 yeras old.

I'm not sure how the PSU itself could have been the issue if it was providing power to the mainboard, although I don't know the history of this PSU or remember why the person gave it to me. Is there any way to test whether the PSU is the problem without buying a new one and risking blowing it again because of MB or CPU issues?

Any other suggestions or advice?

Thanks,
jqpa
 

GotNoRice

[H]F Junkie
Joined
Jul 11, 2001
Messages
9,595
Everything about that PSU that I've found seems to indicate that it was an extremely low-end PSU, even when it was brand new. The fact that it didn't even have a 24-pin motherboard connector is also a bad sign. Did it even have a 4-pin ATX12v connector?

Many older PSUs had most of their power on the 5v rail, as computers at that time used a lot more from that rail. Around the same time 24-pin became more common, most systems also shifted to using a LOT more 12v, and a lot less 5v.

So it could have simply been that, in addition to being a very old PSU, and very low quality, it also was only able to supply very limited 12v output. Attached to a system that required significant (yet normal) power from the 12v rail, that is a recipe for disaster.

About the motherboard? I'm not sure that you are going to know for sure unless you try it. I'd say it's probably still good unless you see anything burnt on the motherboard, but who knows.
 

jqpa

n00b
Joined
Mar 21, 2020
Messages
3
Thanks for the response. There seems to have been two versions of the Ultra 600P: a regular version (ULT-LS600P) and a "gaming" version (ULT-600P). I have the gaming version, and it looks like the build quality was solid, although that could have just been the exterior. It did have the 4pin connector.

What concerns me is that somehow the Seasonic died (I don't remember the details), and then I hooked up a new PSU to the same system and that PSU died without the mainboard even POSTing. So I'm worried about risking blowing another PSU and throwing a lot more money at a previous-gen system, especially when I don't know if the potential issue is the board, the CPU, or both. However, if I can get this running without spending a lot more money it's going to be more enough to cover my needs with the upgrades to 16GB of DDR3 and a DP video card that can run my new 4K monitor at 60hz. I don't really need to spend several hundred to upgrade everything to the current gen right now.

So maybe the best plan is to buy a cheao microcenter PSU, disconnect everything, and see if I can the board to post, and then gradually start adding parts back in. That way I'm not risking too much and I can always return the PSU if everything works and I want something better. If that one blows too then I have to reassess.
 

jqpa

n00b
Joined
Mar 21, 2020
Messages
3
Got a cheap PSU and hooked it up and the MB is booting fine now, but so far only with one stick of RAM. Whenever I try to put in another one it doesn't reach BIOS screen. I had two sticks of Crucial 4GB DD3 running when this was my main rig, and I bought two more, but I can't even get the original 2 running so that's a bit weird. Any of the single sticks boots fine. New video card works also.

I also realized that I'm not getting POST information because my Antec case doesn't actually have a speaker. :/
 

pendragon1

Fully [H]
Joined
Oct 7, 2000
Messages
19,543
Got a cheap PSU and hooked it up and the MB is booting fine now, but so far only with one stick of RAM. Whenever I try to put in another one it doesn't reach BIOS screen. I had two sticks of Crucial 4GB DD3 running when this was my main rig, and I bought two more, but I can't even get the original 2 running so that's a bit weird. Any of the single sticks boots fine. New video card works also.

I also realized that I'm not getting POST information because my Antec case doesn't actually have a speaker. :/
boot with one stick and increase the voltage a bit, ~10%. then try adding another stick.
most case havent come with a speaker for years.
 

GiGaBiTe

[H]ard|Gawd
Joined
Apr 26, 2013
Messages
1,199
Thanks for the response. There seems to have been two versions of the Ultra 600P: a regular version (ULT-LS600P) and a "gaming" version (ULT-600P). I have the gaming version, and it looks like the build quality was solid, although that could have just been the exterior. It did have the 4pin connector.
Nothing about either of those PSUs looks to be of any sort of quality. They look like sketchy dangerous overpriced Ebay specials. From the poor quality photos, it looks like the PCB inside the unit doesn't even take up half of the inside of the unit. It's no real surprise the one in your system exploded.

What concerns me is that somehow the Seasonic died (I don't remember the details), and then I hooked up a new PSU to the same system and that PSU died without the mainboard even POSTing. So I'm worried about risking blowing another PSU and throwing a lot more money at a previous-gen system, especially when I don't know if the potential issue is the board, the CPU, or both. However, if I can get this running without spending a lot more money it's going to be more enough to cover my needs with the upgrades to 16GB of DDR3 and a DP video card that can run my new 4K monitor at 60hz. I don't really need to spend several hundred to upgrade everything to the current gen right now.
A properly built power supply should not die if a fault occurs on the DC side, it should shut down gracefully and be able to be powered back up. Sometimes you have to remove the AC power plug for a minute or so for the protection circuitry to reset. Garbage PSUs usually omit any sort of protections, which is why they explode or catch on fire when a fault happens.

Here's an EVGA 500W unit for $50: https://www.newegg.com/evga-100-w1-500-kr-500w/p/N82E16817438016?Item=N82E16817438016
 

kirbyrj

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Joined
Feb 1, 2005
Messages
26,113
boot with one stick and increase the voltage a bit, ~10%. then try adding another stick.
most case havent come with a speaker for years.
Yeah, some higher end sticks that needed 1.65V wouldn't boot properly at 1.5V. This is how you'd have to go about fixing it.

I had the non-USB3 version of that board. It wasn't too bad as long as you didn't push it hard. There was no heatsink over the VRM IIRC.
 
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