Buzzy EZcool 550W - Worth repair?

[Bungz]

Got this in a machine I picked up locally, immediately on powering the machine I got a really unnerving buzzing from the machine, I powered down and one of the caps (maybe the standby) was blown.

I replaced and the sound went away, but slowly came back, seems to sync with hard drive or 5v activity.

Is this worth saving and if so what is the likely cause?

Thanks!

[Pentium4]

Re: Buzzy EZcool 550W - Worth repair?

Hmmm. Judging by the heatsinks and the way it's placed in the chassis, I'd guess it's a Deer. But nothing else seems like it's a Deer. Cap brand choices, that weird fan daughterboard, Weltrend WT7502. But on the otherhand....Deer is the only company I've seen that uses that interesting method of a heatsink on that 5VSB diode. I guess it could be a Deer.

I think it's definitely worth repairing, It's got an input filter, 35 transformer, good sized toroids and output inductors, fan control thermistor. I'd say replace ALL the caps, oil the fan, and check the values on the minimum load resistors. Also, make sure the joints on the bottom side of the 5VSB section didn't go cold, it looks like that area ran really hot and it sounds like the little caps in that section have gone bad, changing the frequency of the transformer, and creating that annoying buzz. I'm guessing that's the main issue. It's also possible that the resistors slow roasted those awful JEE caps, pushing them out of spec, but not causing them to bulge.

What fan does it use and what are the specs of the silicon?

[Pentium4]

Re: Buzzy EZcool 550W - Worth repair?

I just noticed that that label has the same exact format as this Prudent Way I recently worked on:

[Bungz]

Re: Buzzy EZcool 550W - Worth repair?

Thanks for the reply, I will spec up how much a recap would cost.

The reason why I didn't just lob this was I used them quite frequently in a computer assemblers job about a decade ago.

The cheeky rip off merchant I worked for used to use these as "upgraded" power supply parts in builds, I believe they were charged at around £50!

That said inside doesnt look to terrible, am I right in saying this is more a 350w unit however than a 550?

[stj]

Re: Buzzy EZcool 550W - Worth repair?

hey Bungz, did you mess with that psu?
it looks like the 5v standby has been upgraded with a couple of Panasonic FC's.

[Bungz]

Re: Buzzy EZcool 550W - Worth repair?

Yes the standy was bulging and I had a FC that fit so I swapped that.

As i mentioned it was strange it cured the buzz that the hd activity was causing for about 5 minutes then it came back

[stj]

Re: Buzzy EZcool 550W - Worth repair?

that is strange because that's not the cap you would relate to the harddrive.

[kaboom]

Re: Buzzy EZcool 550W - Worth repair?

Yes the standy was bulging and I had a FC that fit so I swapped that.

As i mentioned it was strange it cured the buzz that the hd activity was causing for about 5 minutes then it came back

Unless you'd like to replace your HDD (and possibly other hardware), either do a complete recap or use another PS.

"Oh JEE, what do we have here?"

I tried using some of those caps for bulk decoupling in a transmitter, and while they did hold some charge, the leakage and ESR were rather high. This was a quick-n-dirty test. The JEEs were 2200u and 1000u 16V, and were replaced with Nichicon HEs of 1500u and 1000u, which were worlds better.

It's not worth trashing your system, or making it go "kaboom" over some lousy caps...

[Bungz]

Re: Buzzy EZcool 550W - Worth repair?

Right I will make a list of caps for it, may have a few good ones in stock.

[kaboom]

Re: Buzzy EZcool 550W - Worth repair?

Right I will make a list of caps for it, may have a few good ones in stock.

Sounds good, but the first you should do a total recap of the standby section, both line side and load side, since it's been a bit toasty.

After that, you should test 5VSB with various loads/resistors, and a meter/scope. You do not want to see any signs of run-away 5VSB at lower loads of 0.1-0.5A, an obvious mobo killer.

Once you're satisfied with the standby supply, only then put your efforts into recapping the main supply.

Obviously, you'd have to do this outside of the computer, so if there are any "accidents," you don't ruin your day.
Not saying you should expect trouble, but some of those two-transistor aux ckts start getting cranky after they've been hot.


Also check joints on/resolder the 5VSB rectifier.

[Bungz]

Re: Buzzy EZcool 550W - Worth repair?

I have ordered a selection of Panny FR/FC/EB caps for it, and yes I will start at the 5v side of things.

How would you go about testing such things, in laymans terms for a novice with just a multi-meter

[kaboom]

Re: Buzzy EZcool 550W - Worth repair?

Try this:



While you won't hear the actual ripple, you will hear any hunting or squegging, which in your supply, is ocurring at an audio rate.

If your recap goes well, you should have a nice, "full" sounding white/pink/brown noise thru the speaker. You may also hear very slight whining, depending on the load and how well that thing's compensated.

In no case should the "tone" dominate- the main audible component after your recap should be the hiss or "rushing."

It'll sound like a blank section of audio tape with the gain/volume way up.

[Bungz]

Re: Buzzy EZcool 550W - Worth repair?

Thanks.

I may just try build that, looks simple enough

[stj]

Re: Buzzy EZcool 550W - Worth repair?

that's an 18" speaker btw.

[kaboom]

Re: Buzzy EZcool 550W - Worth repair?

that's an 18" speaker btw.

21, actually.

[Bungz]

Re: Buzzy EZcool 550W - Worth repair?

Righty

I went balls out and just re-capped the lot as I couldnt be bothered taking it apart again.

Still buzzes! Sounds like extreme coil whine, massively amplified with HD activity.

Any pointers before I harvest my nice panny caps out of it and sling it?

[stj]

Re: Buzzy EZcool 550W - Worth repair?

find out what coil is bitching by pressing on them with a plastic rod or bic pen body.

[Behemot]

Re: Buzzy EZcool 550W - Worth repair?

Oh yeah, good ol' ATX-550JSP. There have been quite a few different boards under this label actually.

[Quaddro]

Re: Buzzy EZcool 550W - Worth repair?

Try this:

wow, can this thing works in other rail?

[Pentium4]

Re: Buzzy EZcool 550W - Worth repair?

What voltage is the 5VSB reading?