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Old 02-08-2017, 01:15 AM   #21
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Default Re: Suggestions for an HP M3970CM repair.

Does it have any gnats on it? One of mine quit posting when a dead gnat shorted out the mother board.
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Old 02-08-2017, 08:32 AM   #22
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Default Re: Suggestions for an HP M3970CM repair.

I have tested the PSU with a power supply tester and the power supply is fine, believe it or not. All the voltages are what they're supposed to be.

The 2-pin connector on the PSU is just like a CPU fan connector. I've been trying to think what it might be used for. My guess would be for lights or something similar. I believe this PSU actually came with the system. The motherboard has some components you'd find on a laptop. It's sort of a hybrid type system.

The first thing I did was test the PSU. I thought the same. Hit the power button, nothing, okay, let's test the PSU. I unhook all the wires from the motherboard, notice that 2-pin connector plugged into the board, said that's not right. Unplugged it, along with all the other connections, and then plugged the PSU into my tester. I turned the power onto the PSU and the PSU fired right up. The power supply is not bad.

I don't understand why he just didn't come to me to help to begin with. I've helped him in the past. Maybe he saw me work on one and just thought it can't be that hard. Not really sure what he was doing. He claims everything in this case is what was in the case when he bought it, minus the video card I bought him a while back. He said he was switching cases. So maybe he removed everything and when he hooked it back up in a new case, when it didn't work, he put everything back. I dunno.
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Old 02-08-2017, 08:36 AM   #23
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Default Re: Suggestions for an HP M3970CM repair.

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Does it have any gnats on it? One of mine quit posting when a dead gnat shorted out the mother board.
gnat as in the insect? No, but I did clean it anyways, with air. There's a heatsink on one of the BGA components. I was thinking it was the northbridge but I have to admit, I don't know much about newer systems. Maybe they don't even have separate northbridges anymore. Maybe they're built into some other chip. It could be the southbridge. It's very close to that PUMP header. The components there all look burned. I thought maybe the heat sink just needed new thermal paste, but there's a chance it somehow fried those components when he plugged the PSU into that PUMP header. One of the caps tested fine, but it was actually discoloured from the heat generated by that heatsink. Maybe somehow he shorted it out and it overheated like crazy and burned all the components.
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Old 02-08-2017, 09:37 AM   #24
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Default Re: Suggestions for an HP M3970CM repair.

Yeah, it had a dead gnat belly up. After blowing the dang thing out of the case it started right up. So watch out for flying insects getting in one.

I would bet some stuff got burned up from that pump header getting power. What, I have no clue, but I think it will take more time to fix than it's worth. A new board will probably be cheaper. I'll spend a little more money on a good car, getting it restored, but not an old computer.
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Old 02-08-2017, 09:43 AM   #25
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Default Re: Suggestions for an HP M3970CM repair.

could you use a power supply low amps etc and feed that connector with power and use freeze spray and see whats overheating etc?
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Old 02-09-2017, 04:13 PM   #26
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Default Re: Suggestions for an HP M3970CM repair.

Rhomanski,

I'm with you at this point on this board. Even though I can't seem to find the board for less than 220$ or so (working), I think it's just bad timing. I wouldn't be surprised if I looked again I could find it cheaper.

Vinceroger69,

I guess I could, but at this point in time, I think I'm just going to say the board isn't repairable and look for another. After a certain point, I have to ask myself, is it worth putting anymore time into this. How much am I making off of it, how much time have I spent working on it? Sometimes, it makes more sense to sell a customer a new board for 100$ - 200$ than it does to spend 2 weeks trying to track down a 50 cent component, if that makes any sense.
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Old 02-09-2017, 07:09 PM   #27
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Default Re: Suggestions for an HP M3970CM repair.

I found the board on e-bay listed as-is for 40$, free shipping. When I was reading the description, the seller said there were errors when I tried copying files from the hard drive, so I'm selling this board as-is. To me, that just sounds like a dying hard drive and nothing motherboard related. I'm a bit worried though, maybe they lied and there's something else going on.

Anyway, we'll see. The customer already looked for a refurbished board and could only find the 230$ish boards, so if I can get this working for 40$, that'd be good. What do you guys think? Was it a mistake buying that board as-is?
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Old 02-09-2017, 09:23 PM   #28
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Default Re: Suggestions for an HP M3970CM repair.

No real difference unless the $230 boards have a decent warranty. Any secondhand parts could have issues.

But yes, it could have been bad HDD, cable, power supply, bad RAM... Who knows?

You'll only find out when it arrives, I suppose.
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Old 02-10-2017, 07:38 AM   #29
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Default Re: Suggestions for an HP M3970CM repair.

Yeah, it's a risk. If the board actually works, I think it's a good deal, but anything that says as-is really worries me. Sometimes, the people straight up lie. For example, we bought a broken 360 off e-bay, being sold as-is. We asked the person if the DVD drive had ever been replaced. He said nope. Said he was playing it yesterday, it froze for the first time, so he's selling it. We got the 360 and of course, he straight up lied. We spent a good amount of time fixing it, but we did fix it. The DVD drive had been replaced. But whoever replaced it didn't know what they were doing and never transferred the drive-key from the old drive. So, the 360 could only play DVDs, it'd never play video games.

We contacted the original seller. He said he couldn't believe we actually got it working. He said he bought it off e-bay thinking he could fix it with baking it in the oven, but when it didn't work, he just sold it and suggested we do the same. Just lie and resell on e-bay he says.

With things like that, even though it's being sold as-is, you can get your money back, because they lie. But usually you have to pay return shipping. I guess we're taking a risk. Personally, I don't think this motherboard is worth 220$. I think used, 40$ is a good price. I'm hoping the guy isn't lying and it really was hard drive issues. I guess we'll see.
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Old 02-13-2017, 03:39 PM   #30
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Default Re: Suggestions for an HP M3970CM repair.

This sucks. Replacement board came today. Exact same symptoms. Absolutely no power what's so ever. Tested the PSU again, everything's good. Tried jump starting the board, just in case the button was bad, nothing. I'm guessing it's now the CPU that's fried.

There's a chance the RAM is fried as well, but I don't have any way to test, it's DDR3 and I don't have a system that can use DDR3.
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Old 02-13-2017, 06:07 PM   #31
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Default Re: Suggestions for an HP M3970CM repair.

umm fried/failed ram wont stop the board from powering on since ram is powered from the 3.3v rail. quite unlikely the ram fried. at most, the board will power on but play dead with faulty ram (no beeps). but if u remove the ram, the board will start beeping and complaining. try powering up without the ram plugged in to rule out the ram as shorted. if it still wont power on with the cpu+board only then the problem is the cpu.
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Old 02-13-2017, 06:37 PM   #32
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Default Re: Suggestions for an HP M3970CM repair.

ChaosLegionnaire,

Thank you for your response. Are you sure a bad stick of RAM couldn't prevent a computer from starting? I'm thinking if there's a short to ground, it could very well prevent a computer from starting. Anyway, I had already tried to rule a short to ground in the RAM out by removing the RAM completely, before I came here saying the CPU was dead. It did the exact same, absolutely nothing!

I believe this PSU is the OEM PSU that comes with this PC. There's a chance that multiple users have fried their systems by plugging this power connector into the motherboard. You know how a CPU fan power connector looks? There's one of those that come out of the PSU. Not really sure what a person would use it for. Pump, lights, etc would have the same type of connector that this wire has. To someone who doesn't know anything about computers, I could see them mistakenly thinking this wire plugs into the board. Makes me wonder if the seller on e-bay lied and did the same thing, or if the CPU really is dead.

Anyway, I ordered a replacement CPU. I've talked it over with the customer, he's going to pay me 200$. I'm spending a little less than a hundred on parts. I think that's a pretty fair price.

If the CPU is in fact dead (and it seems like it might really be), it makes me wonder if the old board is dead. Perhaps it was just the fried CPU and no damage was done to the board....any chance when I get the working CPU that there could be something shorted in such a way on the old board that if I plug a working CPU into the socket, it'd fry the new CPU?

Thanks!
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Old 02-13-2017, 08:29 PM   #33
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Default Re: Suggestions for an HP M3970CM repair.

If the CPU VRM high side MOSFETs are shorted it could quite likely send 12v into the CPU. Since CPU VCORE is normally about 1v that will blow the CPU.

If the VRM controller is faulty it could also do something similar.

I would be surprised if either of those happened due to the incorrectly connected PSU, though.
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Old 02-14-2017, 12:42 AM   #34
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Default Re: Suggestions for an HP M3970CM repair.

If the CPU is in fact dead (and it seems like it might really be), it makes me wonder if the old board is dead. Perhaps it was just the fried CPU and no damage was done to the board....any chance when I get the working CPU that there could be something shorted in such a way on the old board that if I plug a working CPU into the socket, it'd fry the new CPU?

How much is the cheapest cpu that will fit it?
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Old 02-14-2017, 11:11 AM   #35
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Default Re: Suggestions for an HP M3970CM repair.

Around 60$, from what I could find. He didn't have the cheapest, he didn't have the nicest. He had about a mid-range 6-core from the list of supported CPUs. I think there were two slower 6-core this supported, two faster 6-core processors, and then a bunch of 8-core.
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Old 02-14-2017, 11:48 AM   #36
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Default Re: Suggestions for an HP M3970CM repair.

http://support.hp.com/us-en/product/...ent/c03353629/

Here's a link to the supported CPUs. He has the AMD FX-6120
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Old 02-14-2017, 02:24 PM   #37
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Default Re: Suggestions for an HP M3970CM repair.

Is it in the original case? There aren't any incorrectly positioned mounting standoffs under the board somewhere are there?
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Old 02-14-2017, 06:59 PM   #38
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Default Re: Suggestions for an HP M3970CM repair.

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Is it in the original case? There aren't any incorrectly positioned mounting standoffs under the board somewhere are there?
It's in the original case and there aren't any incorrectly positioned mounting standoffs. I checked that and also looked for screws that might be hiding under the board. I learned to check for that stuff early on. One time, a long time ago, there was a screw under the board. Turned it on without looking, fried the board. Ever since, I always check. Good call though, I dunno if many people would think to look.

I'm thinking the CPU is definitely dead. I thought that early on, because of the symptoms. I've seen boards that had issues before, but none that had the symptoms here. I mean, I'm sure if something was shorting to GND, the board might be intelligent enough to prevent the PSU from turning on, but I dunno, even then, I'd think there'd be more than what we have now.

I ordered the replacement CPU, just have to wait until it arrives. I see the guy printed a shipping label right after I bought it, but has yet to ship it. Sometimes that bugs me a little. How hard is to put it in the mail box? I guess if you're selling a lot of items though, it might take a little bit of time. I bet if I took a couple days to pay though, they'd say something!
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Old 02-14-2017, 07:13 PM   #39
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Default Re: Suggestions for an HP M3970CM repair.

I guess the board and CPU really are dead. It surprises me, but I've seen weirder things.

Yeah I think some people only ship once or twice a week, it'd be uneconomic to drive to the post office every day.
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Old 02-15-2017, 02:24 PM   #40
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Default Re: Suggestions for an HP M3970CM repair.

It doesn't really surprise me that the CPU is dead, but I guess I don't know as much about motherboards as I should. I learned about them in college but they've changed a bit since then.

This is how I was looking at it. The customer sent 12V to GND. I was thinking the CPU shares the same GND as everything else. I was thinking that 12V just fried a bunch of stuff. I don't understand why the RAM wouldn't be affected because it's on the 3.3V rail. This doesn't make sense to me, so I still am lacking a full understanding.

What are the different rails of a computer motherboard? Someone said 3.3V, so I know there's a 3.3V rail. There's a 12V rail, there's a 5V rail, right? The CPU uses around 1V, is there a 1V rail?

My limited understanding of a rail is just a trace that provides electricity to multiple components. My understanding of a plane is the same, but for GND. My understanding is the rails and planes are generally thicker traces. Please correct me if I'm wrong.
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