New PSU, system won't boot (continued)

This is in continuation of my earlier thread where I couldn't post further because of some token issues

Previous thread
PSU went up in smoke. New PSU won't boot PC


Anyway, So I got a new motherboard, a budget ASUS board and also a new APC 600 VA motherboard for added protection. I set everything up and when I turned it on, the PC booted and it ran fine for a while. Later I opened the case again to align the IO shield with the motherboard and then when I switched it on, everything was fine, then I moved away from my desk and could hear some clicks coming from the UPS. I came back and saw thr display gone, the monitor was in idle mode, the fans were spinning and the power and motherboard LED were on. The HDD Led was off and so was that of the keyboard.

What could have gone wrong now? Please advise

While APC is probably the best known UPS maker, it is possible you got a bad one so removing it for a test is a good idea. However, since you indicated the system ran fine for awhile, that is a good sign that is fine.

FTR, I am a huge proponent of using a "good" UPS with AVR with every computer. Sorry AddRAM, but a surge and spike protector is little more than a fancy and expensive extension cord!

For "normal" surges and spikes, surge and spike protectors just chop off ("clamp") the tops of the waveforms leaving a very ugly waveform for the PSU and motherboard regulator circuits to deal with. This puts added stress on those components.

For excessive surges and spikes, a surge and spike protector just trips a breaker and kills power to your computer with a hard "crash" - hardly helpful. And for low voltage events (dips - opposite of spikes; sags - opposite of surges; brownouts - long duration sags) a surge and spike protector does absolutely nothing.

A UPS with AVR (automatic voltage regulation) will attenuate or boost the voltage as necessary providing a much cleaner (if not a "true") waveform to the connected devices. Note that power during a full power outage is just icing on the cake. It is the AVR that really matters that no surge and spike protector can provide.

So kudos to you, probuddha, for using a UPS.

BTW, unlike Li-ion batteries, you really don't have to let the UPS SLA (sealed lead-acid) batteries fully charge before first use. If the batteries are not charged, you just don't have the low-voltage event protection they provide until they are charged. The UPS will still provide AVR protection for high voltage events and "trickle" charge the batteries at the same time.

You might also look at the sensitivity settings on the UPS. For most regions and most power grids, the default setting is just fine. But for others, if set too sensitive and the UPS may try to kick over to batteries too often unnecessarily.

Also, 600VA should be plenty big for the computer itself but may be on the small side when the computer is being taxed hard (like with heavy gaming) while also protecting a large, older monitor/TV, external drives and other devices too.

Later I opened the case again to align the IO shield with the motherboard

This concerns me. The I/O shield, when properly snapped into the case is automatically properly aligned. And the motherboard is too if properly mounted to the case. So I don't understand what alignment you needed to do. Did you unplug the computer from the wall before doing this re-alignment, or at least flip the PSU's master power switch to off? If not, there was still +5Vsb standby voltage running through many points on the motherboard, including the USB and network ports sticking through the I/O shield. If that +5V was accidently shorted to another circuit, damage may have occurred.

If there was a short, the UPS may sense this as a fault and attempt to shut down to protect the connected devices. The UPS may also shutdown to protect the equipment if the wall outlet is not properly wired or grounded. So I recommend you check your outlet wiring too.

Every home and every computer user should have access to a AC Outlet Tester to ensure your outlet is properly wired and grounded. I recommend one with a GFCI (ground fault circuit interrupt) indicator as it can be used to test bathroom and kitchen outlets too. These testers can be found for your type and voltage outlet, foreign or domestic, at most home improvement stores, or even the electrical department at Wal-Mart (if you have Wal-Marts in Calcutta). Use it to test all the outlets in the house and if a fault is shown, have it fixed by a qualified electrician.

Itaregid said:

For excessive surges and spikes, a surge and spike protector just trips a breaker and kills power to your computer with a hard "crash" - hardly helpful.

That is not how any protection works. Surges and spikes are microsecond events. Disconnecting takes milliseconds or seconds. How many hundreds consecutive surges would pass through a disconnecting protector? Too many to count.

Anyone can read spec numbers. A UPS typically claims to absorb hundreds of joules. Protection could not be any tinier. A power strip protector may absorb ten times more - thousands of joules. Meanwhile a potentially destructive surge is hundreds of thousands of joules. Both UPS and power strip are near zero protection.

Meanwhile a solution routinely found anywhere damage cannot happen is about where hundreds of thousands of joules are harmlessly absorbed. Nothing adjacent to an appliance claims that protection. And nothing can disconnect fast enough. Unfortunately those urban myths combined with wild speculation often recommend near zero protection with massive profit margins. Effective solutions that cost tens or 100 times less money are little known.

UPS does nothing useful for the OP's problem. Connecting directly to a wall receptacle is a best test - and puts no hardware at risk. Since a UPS does nothing to protect hardware. Since any protection that a UPS might do is already inside every computer's PSU. Spec numbers confirm this.

You need to connect to another wall power socket, as to determine if that wall power socket is good or not.
By leaving the PC on without doing any things on the PC, idle.
Wall power socket is that it have a very thick wires, instead on extension cord.

UPS will not help at all.
UPS purpose is to provide supply to the PC should there be a power surge or short circuit.
Meaning it will continue to supply power to the PC to handle proper shutdown after saving files.
Normally UPS is good for 1 time, as the connection from the power point to UPS may be damaged.
Your problem is from the PC PSU and PC components.

You may have to do some troubleshooting yourself.
That is to connect 1 device and later another device, such as HDD & other components.
As there may be caused by any of the devices &or connection.
I would say that the PSU may not be the issue, after keeping changing.

westom said:

That is not how any protection works.

Sure it is - assuming the device is working properly.

Surges and spikes are microsecond events.

Spikes might have such short durations but surges, by definition, roll in and out and can last for several seconds - though a few milliseconds is more typical.

Disconnecting takes milliseconds or seconds.

Seconds??? That's totally false! Come on! You say anyone can read specs, then please do that before posting such inaccuracies! Not even budget protectors take that long. A simple look at MOV technologies (the primary device used in surge and spike protectors - including those in UPS) react much faster than that.

Source: GE Energy - Power Quality Surge Protective Devices, Response time ratings,

The response time of a typical MOV component is
1000 times faster than the time it takes for a surge to
reach it’s peak voltage potential as defined by IEEE C62.41
surge test waveforms. (approximately 1.2 microseconds)

westom said:

hundreds of thousands of joules

Sorry, but that is completely false. It seems there is also a lack of understanding as to how a good UPS works too. A UPS does not have to absorb massive amounts of joules, they just need to detect the anomaly and compensate or cutover to battery backup long before a surge of destructive levels peaks. And since any 1/2-way decent UPS is an "intelligent" device using a microprocessor operating at 100s of MHz clock speeds, reacting in time is no problem. If anything, you just proved my point as a decent UPS will cut over to battery backup in 10ms or less with 4ms common for better a UPS.

Note this 600VA APC UPS has a typical cutover (transfer) time of just 6ms, 10 max.

As for your nonsense claim of seconds, note this $13.50 budget APC Surge and Spike protector as a response time of 1ns - that's nanosecond, 1 billionth of 1 second.

Of course nothing will protect a system from a direct lightning strike but for the vast majority of anomalies that come off the grid, or for those introduced from faulty devices within the home, there is nothing better than a "good" UPS with AVR. Only a UPS can signal your computer to "gracefully" save your open documents, close all running programs and properly shutdown Windows and power off the computer.

Eric3742 said:

Normally UPS is good for 1 time, as the connection from the power point to UPS may be damaged.

"Normally" good for 1 time? Ummm, not at all. A UPS is designed for years of repeated use. The only restriction between uses involves ensuring there is enough charge in the batteries to support another "graceful" shutdown - typically no more than 5 minutes of runtime.

A surge and spike protector, on the other hand, is more like a motorcycle helmet and if it saves your noggin once, it did its job and should be replaced with a new one.

I agree, as I noted above, the UPS should probably come out of the circuit while troubleshooting this problem, then put back in circuit if not found to be the problem. And again, power during a full outage is just a bonus. The AVR is the key advantage to using a UPS.

Just to let you know this issue is solved.

This thread was a continuation of the previous thread, a posting issue as mentioned in post one,

PSU went up in smoke. New PSU won't boot PC

Which has since been marked solved by the OP,

probuddha said:

Got a new Cooler Master B500 V2.0 PSU and system is up and running again.

Thank you so much everyone for all your help

Feel free to carry on your conversation as long as it stays friendly.