?dead CPU, new MoBo and PSU already tried

[XeCaraeos]

So I made my own comp about 4 yrs ago now, I've had a couple of PSU's die on me before I realised that it actually wanted more power.... anyway:

last week there was a bang and an... interesting smell. I immediately shut the computer down and checked inside the case, but couldn't see anything obvious... and the smell was pretty well dispersed. I restarted, and everything was working fine.

Fast-forward 4 days, I go to turn the comp on in the morning, and (after a half-second burst of internal lights and the beginnings of a whirr) nothing.

Upon opening the case, nothing obvious again. Upon turning off and on the mains power/PSU I could get that same half-second burst of internal lights and the beginnings of a whirr, When I plugged in a new PSU I had the same issue.

When I started pulling out cables and plugging them back in, the only one causing an issue seemed to be the 4-pin CPU power supply... (but without CPU power, obviously nothing happened except whirring and lights)

My immediate diagnosis was that something had gone on the MoBo (Motherboard), but 1 brand-new MoBo later, I'm still getting nothing beyond fans and internal lights (my MoBo beeper doesn't work on the new mobo)
is this likely to be a CPU problem?

my build (at time of death) was:
AMD FX 8120
ASUS M5A78L-LE (MoBo, CPU 4-pin power supply now seems borked, and upon removal a capacitor fell off)
4x4GB DDR3 ram (Corsair, I can't remember part No)
Nvidia 560GTX (dualscreening via DVI)
Corsair 600W PSU, which seems fine
2x SATA hard drives (which appear to be running fine, think it's a 250GB and a 1TB)
DVD read/writer
PCI expansion with 4+1 USB 2.0

I have tried:
new Corsair 750W PSU (makes no difference)
new MSi 970A-G43 MoBo (CPU 8-pin power supply works fine, but still black screen, and doesn't fit the motherboard beeper (wrong pin-alignment))
new NVidia Geforce 210 (makes no difference)

I am thinking of buying a cheap AM3+ CPU to test, but if it turns out to be the CPU, I might just get an i7, so want to really avoid this.....
Any and all solutions much appreciated
Thanks!

 

[Forgotten031511]

I can tell you right now, it seems a lot more is at play here. You said you have had several PSU fail in 4 years? That is a lot, most GOOD PSU's will last much longer than that. So having multiples fail...what's going on? I see you have Corsair PSU, so I don't think it is a cheap brand being the problem. Is the power to your PC stable or do you have power surges often, and are you using a surge protector?

Also, a capacitor fell off?!?! Clearly that's an issue. Any thing like that happening will cripple a system, without a doubt. Did you try to run the system again with the damaged board missing a capacitor? If so, you may have damaged other components that you don't know about yet.

 

[XeCaraeos]

I can tell you right now, it seems a lot more is at play here. You said you have had several PSU fail in 4 years? That is a lot, most GOOD PSU's will last much longer than that. So having multiples fail...what's going on? I see you have Corsair PSU, so I don't think it is a cheap brand being the problem. Is the power to your PC stable or do you have power surges often, and are you using a surge protector?

Also, a capacitor fell off?!?! Clearly that's an issue. Any thing like that happening will cripple a system, without a doubt. Did you try to run the system again with the damaged board missing a capacitor? If so, you may have damaged other components that you don't know about yet.

I think it was a pair of 550W (both of which went within a few months) and then possibly a cheap 600W that failed, I since switched to Corsair in the hope of quality. I use a surge protected gang-of-6 extension to run my comps off, and the house is wired properly (I should know, I helped with most of it), circuit breakers for upstairs and downstairs sockets, and a master, which have tripped on occaision, but never to the detriment of either of my PC's or my laptop.

As for how stable the supply is - I think fairly stable... but I have no way of knowing beyond the fact that I've only on 2 occaisions lost power supply, on both occaisions, someone had blown a fuse else where, and tripped the circuit breaker.

Yeah, the capacitor falling off was rather concerning, as I have no idea whether that was me rummaging around and being clumsy or if I've actually run it like that for a while! Obviously I only found it out when I pulled the old MoBo out.

 

[Forgotten031511]

Well, with a capacitor off the MB you clearly have knowledge of electricity (so I don't need to explain that to you) I cannot confirm if the CPU is bad/damaged/or even the problem.

The MB is the center control for the entire PC, duh right! So if the MB is damaged it is too hard to confirm if the CPU is dead or not. If you cannot get the MB replaced from warranty, get a new system as you mentioned before. But if you are looking at gaming, get the i5 4690k. The i7's are a waste of money in gaming as most games don't use the hyper-threading. The only difference in the i5 and i7 is hyper-threading. Actually most i5's compared to their i7 counter CPU get better FPS in games. Unless you need extra multi-tasking, save the money and get a i5.

 

[XeCaraeos]

Well, with a capacitor off the MB you clearly have knowledge of electricity (so I don't need to explain that to you) I cannot confirm if the CPU is bad/damaged/or even the problem.

The MB is the center control for the entire PC, duh right! So if the MB is damaged it is too hard to confirm if the CPU is dead or not. If you cannot get the MB replaced from warranty, get a new system as you mentioned before. But if you are looking at gaming, get the i5 4690k. The i7's are a waste of money in gaming as most games don't use the hyper-threading. The only difference in the i5 and i7 is hyper-threading. Actually most i5's compared to their i7 counter CPU get better FPS in games. Unless you need extra multi-tasking, save the money and get a i5.

Just to clarify - the original MoBo was the one that has lost a capacitor, the second one is physically fine, but doesn't change the black screen of nothing-ness.

Then onto your next paragraph - I always thought it was more of a skeleton upon which to build a body, not the Brain, but without it just a formless mass of stuff that can't actually do anything.

Anyway:you're saying "if you've got a dodgy MoBo, don't bother confirming if the CPU's alive or not, just get a new MoBo & CPU and start (more-or-less) from the beginning"?

As for i5's vs i7's - thanks for the advice, but I also do a lot of multi-tasking as it's also a work comp, so an i7 is likely the way I'll go - any suggestions on that?

 

[Forgotten031511]

The MB is not just a skeleton, think of it as the nervous system. It allows all the components to communicate (i.e. CPU, RAM, GPU, etc). Not only that, but the MB has the BIOS (Basic Input Output System) which is required for ANY electronic system. So the MB is much much more than a skeleton, the case is a skeleton, the MB is like the central nervous system if you want to compare it to a human. If you are paralyzed, you can't feel pain in your leg, so we don't know if something is wrong...make sense?

Moving onto the i5 vs i7, if you are going with the i7 the 4790K Devils Canyon is the best option right now...unless you really wanna break the bank and go to the new 2011 Socket and 8 core CPU ($1000 for the CPU alone).

 

[westom]

As for how stable the supply is - I think fairly stable... but I have no way of knowing beyond the fact that I've only on 2 occaisions lost power supply, on both occaisions, someone had blown a fuse else where, and tripped the circuit breaker.

No relationship exists between wattage and quality. Or between wattage and life expectancy. For example some power supplies are at greatest stress when providing half power. Most all computer only consume maybe 200 watts and never more than 350. We simply tell computer assemblers (without electrical knowledge of other numbers that apply) to buy 700 watt supplies. That keeps help lines free.

A power controller (another part of the power system) determines when a PSU can power on, power off, and when the CPU is permitted to execute. Solution starts by first learning what a power controller is doing and the many inputs to that controller. A front panel button is one input. Another comes from monitor circuits inside a PSU.

A defective motherboard will not damage a properly designed PSU. For example, you can perform the test. Short all PSU outputs together (create a maximum load). A powered on PSU is never damaged. In fact, an Intel ATX spec even defined how thick that shorting wire must be. Because even an overloaded PSU is not damaged.

Same applies to a motherboard. A PSU failure must not ever damage a motherboard, disk drive, etc. As was true even with the original PC and with electronics long before PCs existed.

Most failures are attributable to manufacturing defects. Defects that can cause failures even years later.

To obtain a useful answer (to identify a defective power supply that still boots and runs a computer) means numbers from a digital meter. Since step one is to determine what the power controller is doing and what inputs to that controller are requesting. Otherwise, just ignore everyone and keep replacing good parts until something works.

 

[XeCaraeos]

As for how stable the supply is - I think fairly stable... but I have no way of knowing beyond the fact that I've only on 2 occaisions lost power supply, on both occaisions, someone had blown a fuse else where, and tripped the circuit breaker.

No relationship exists between wattage and quality. Or between wattage and life expectancy. For example some power supplies are at greatest stress when providing half power. Most all computer only consume maybe 200 watts and never more than 350. We simply tell computer assemblers (without electrical knowledge of other numbers that apply) to buy 700 watt supplies. That keeps help lines free.

A power controller (another part of the power system) determines when a PSU can power on, power off, and when the CPU is permitted to execute. Solution starts by first learning what a power controller is doing and the many inputs to that controller. A front panel button is one input. Another comes from monitor circuits inside a PSU.

A defective motherboard will not damage a properly designed PSU. For example, you can perform the test. Short all PSU outputs together (create a maximum load). A powered on PSU is never damaged. In fact, an Intel ATX spec even defined how thick that shorting wire must be. Because even an overloaded PSU is not damaged.

Same applies to a motherboard. A PSU failure must not ever damage a motherboard, disk drive, etc. As was true even with the original PC and with electronics long before PCs existed.

Most failures are attributable to manufacturing defects. Defects that can cause failures even years later.

To obtain a useful answer (to identify a defective power supply that still boots and runs a computer) means numbers from a digital meter. Since step one is to determine what the power controller is doing and what inputs to that controller are requesting. Otherwise, just ignore everyone and keep replacing good parts until something works.

I have identified a defect in the original MoBo - a capacitor has broken!

What I want to know is what else that might have damaged in the process when I didn't notice the damage initially and kept running the rig.

 

[westom]

I have identified a defect in the original MoBo - a capacitor has broken!

What I want to know is what else that might have damaged in the process

Your motherboard has a plane, end to end, that is solid copper. This ground plane still has voltage differences between both ends of that board. It is called noise. Capacitor, sprinkled all over the board, only reduces that noise. A missing capacitor might mean a signal (a logic 0 to 1 transistion) fails once every 80 years instead of once every 500 years. Noise does not damage hardware.

Simply replace that capacitor with one of equal farads, voltage, and shape so that software crashes occur less often. Hardware damage is a discussion of completely different items.

BTW, least likely damaged item is a CPU. What exists on each motherboard makes obvious why.

Power 'system' is one item that can make anything else (memory, disk drive, etc) appear to be defective. A good tech first confirms integrity of the power system (using what was previously recommended). PSU is only one component of that 'system'. Later move on to other suspects.