Primary Filtering Insufficient?

**Toasty** · 03-03-2010, 10:14 PM

Re: Primary Filtering Insufficient?

Weak secondary filtering caps will cause this as the UPS switches from line to battery. What model APC UPS? Age of system?

**bhvm** · 03-03-2010, 10:59 PM

Re: Primary Filtering Insufficient?

System is 3 years old and is running like a champ, unless this ups switch over.
Ups is apc back-ups 500 es. Other similar pc on that ups works fine during switch over.

**Toasty** · 03-03-2010, 11:14 PM

Re: Primary Filtering Insufficient?

Forgot... Could also be weak/bad VRM caps on mobo.

UPS is only capable of 300 watts. At 230v that's only 1.3 amps. Could be causing enough of a drop at switchover to make the system shut down. I'd go at least 750 watts for a standalone system.

hmmm... A little more looking. Output of UPS is simulated/stepped sinewave. If the PSU in system is a PFC type, they have been known to have issues with non-pure-sinewave.

**bhvm** · 03-03-2010, 11:25 PM

Re: Primary Filtering Insufficient?

Originally posted by Toasty

Forgot... Could also be weak/bad VRM caps on mobo.

UPS is only capable of 300 watts. At 230v that's only 1.3 amps. Could be causing enough of a drop at switchover to make the system shut down. I'd go at least 750 watts for a standalone system.

hmmm... A little more looking. Output of UPS is simulated/stepped sinewave. If the PSU in system is a PFC type, they have been known to have issues with non-pure-sinewave.

Nice to know.....

I did some Trial and error....

1> Other 2 Hi-end PC on Same UPS... Working fine during switchover
2> Other SMPS in Same AMD PC..... Working fine during Switchover...
3> SAME SMPS in Other Intel PC.... Working fine all time........Wow?

I first thought SMPS was bad... but how would you explain Point 3?

Is is possible that SMPS is good but not Good enough for the AMD PC?

What can be done to repair it?

And yeah......... SMPS is gernic OEM one. NO PFC nothing... has 2 fans.

**Toasty** · 03-03-2010, 11:58 PM

Re: Primary Filtering Insufficient?

PSU is dropping enough to cause the AMD board to lose voltage and shut down. May be very sensitive to minor fluctuations. Intel may not be as sensitive.

I'd pull the PSU and open it for checking and possible recapping. But, if you leave the setup as you listed above, everyone should be happy.

**bhvm** · 03-04-2010, 05:00 AM

Re: Primary Filtering Insufficient?

I did.nt get the system thing your're talking about. I ripped open the power supply. No visible damage or bulging caps. Shall i try to find the biggest 16v caps around, stuff it into 5v and 12v rails, then check by emulating blackouts?

**370forlife** · 03-04-2010, 06:35 AM

Re: Primary Filtering Insufficient?

Cheap power supply? Some caps can fail without showing.

**bhvm** · 03-04-2010, 06:55 AM

Re: Primary Filtering Insufficient?

Originally posted by 370forlife

Cheap power supply? Some caps can fail without showing.

Exactly....

It looks more or less like this one Internally-

https://www.badcaps.net/forum/showthread.php?t=7588

**bhvm** · 03-04-2010, 07:00 AM

Re: Primary Filtering Insufficient?

What a nice place this forum is....

I hunted old topics and found nice info, Really enjoying it.

Toasted cat, I',m still waiting for your opinion...

Will big caps on 12v and 5v help? Where shall i put them?

One More thing, I had a little 'experiment' today.
I put a Monster 440v 50 MFD cap in parallel to the mains input of SMPS for PF correction and better stability.
Cap buzzed and vibrated a lot...so I promptly shut it off.

Did I do something wrong? SMPS is still working fine.
How to go about PF correction?

**stj** · 03-04-2010, 11:41 AM

Re: Primary Filtering Insufficient?

that cap should go after the rectifier - AC will make a BANG!

**Toasty** · 03-04-2010, 12:49 PM

Re: Primary Filtering Insufficient?

Originally posted by bhvm

I did.nt get the system thing your're talking about...

You said:

I did some Trial and error....

1> Other 2 Hi-end PC on Same UPS... Working fine during switchover
2> Other SMPS in Same AMD PC..... Working fine during Switchover...
3> SAME SMPS in Other Intel PC.... Working fine all time........Wow?

and I said:

"But, if you leave the setup as you listed above, everyone should be happy. "

Why not leave the working setup in place?

**Toasty** · 03-04-2010, 01:05 PM

Re: Primary Filtering Insufficient?

Originally posted by bhvm

How to go about PF correction?

PFC is either present or it's not. You can't "build-in" PFC to a non-PFC supply. Completely different design.

Originally posted by bhvm

One More thing, I had a little 'experiment' today.
I put a Monster 440v 50 MFD cap in parallel to the mains input of SMPS for PF correction and better stability.
Cap buzzed and vibrated a lot...so I promptly shut it off.

Did I do something wrong? SMPS is still working fine.

Yes, you did something wrong. If you do not know what, then I am sorry, but I think your best option is to acquire a new PSU.

I am very concerned that you may injure yourself or others with experimentation such as this.

Toast

**bhvm** · 03-04-2010, 08:54 PM

Re: Primary Filtering Insufficient?

Sorry about that.

I got a new PSU.

This time, 2X heavier and 3x Costlier.
I just opened it up to take a peek inside... Wow
Full of components and BIG heatsinks. Active PFC and other loads of Protection circuits.

My older one looks like an empty box in comparison to this one.

One last question but,
Will putting new/Bigger caps on old SMPS Secondary one help? Just as a backup SMPS or for bench testing? Or shall i dump it altogether?

**Toasty** · 03-04-2010, 10:46 PM

Re: Primary Filtering Insufficient?

I would keep it around for emergency -temporary- replacement if another one fails. That supply looks to have the 2-transistor 5vsb which has been known to kill motherboards.

Happy you got another. I take it that it does not drop out when the UPS switches over?

Toast

**370forlife** · 03-05-2010, 06:35 AM

Re: Primary Filtering Insufficient?

Originally posted by bhvm

Sorry about that.

I got a new PSU.

This time, 2X heavier and 3x Costlier.
I just opened it up to take a peek inside... Wow
Full of components and BIG heatsinks. Active PFC and other loads of Protection circuits.

My older one looks like an empty box in comparison to this one.

One last question but,
Will putting new/Bigger caps on old SMPS Secondary one help? Just as a backup SMPS or for bench testing? Or shall i dump it altogether?

Post a pic of your old psu and we can help you fix it up for testing or for backup use.

**bhvm** · 03-05-2010, 09:44 AM

Re: Primary Filtering Insufficient?

Originally posted by Toasty

I would keep it around for emergency -temporary- replacement if another one fails. That supply looks to have the 2-transistor 5vsb which has been known to kill motherboards.

Happy you got another. I take it that it does not drop out when the UPS switches over?

Toast

Great one Gurus, Nice to see both of yours interest to help me fix it up.

It looks exactly like one reviewed here-

https://www.badcaps.net/forum/showthread.php?t=7588

I can see lots of primary filtering is empty... caps are small... and heatsinks are light.

Do you folks want to see my new SMPS Pics and can comment about its quality?

It boasts of all Active PFC, OVP, SCP, UVP and loads more... lets verify what are these manufacturers up to... right?

**bhvm** · 03-05-2010, 10:12 AM

Re: Primary Filtering Insufficient?

So, here is my NEW SMPS,

Did i get a nice one?

See the pics-

**stj** · 03-05-2010, 11:20 AM

Re: Primary Filtering Insufficient?

i like the shell, good for checking the caps

cant make out the name on the secondary's though.

**Toasty** · 03-05-2010, 12:44 PM

Re: Primary Filtering Insufficient?

It will be sufficient for what you need it for. I don't care for how it did in the reviews:

http://www.overclockersclub.com/revi...rix_500t/3.htm

From the Conclusion page:

Cons:

* Very poor efficiency
* Lack of active power factor correction
* Failure of the 3V3 and 5V0 DC lines at high loads
* Internal power supply transformer buzz at high loads

bleah!

Primary Filtering Insufficient?

Primary Filtering Insufficient?

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