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**clcorbin** · 05-08-2009, 11:23 AM

Re: Well, I just joined the club. And the forum! Antec TP 550 EPS died.

New caps are installed, but power supply is still dead as a door nail. I've tried manually powering it up (green to ground) and also plugging it back into the computer and trying to turn it on that way. I've also also measure the voltages at each of the pins on the main connector with the power supply plugged in and on and there are no voltages at any pin. I did verify that the fuse is good (reading about 0.2 ohms and I have 120VAC at both ends of the fuse with the switch on).

This power supply was working 24/7 until I shut the computer down a couple of weeks ago. Does anyone have any good links to general power supply trouble shooting methods or anything specific to this Antec 550 EPS 2.0 supply? Any good low hanging fruit to check out before I dig into this thing?

**Toasty** · 05-08-2009, 01:34 PM

Re: Well, I just joined the club. And the forum! Antec TP 550 EPS died.

ALL new caps, or just the leaky ones? That entire secondary of anything marked Fuhjyyu or the other listed bad caps should be recapped.

You should have a standby voltage (+5volt) from ground to the purple wire. It's what illuminates the LED on the mobo and powers the the startup circuit. Plug the supply in and turn it on by its power switch. If that voltage is missing, start tracing it backwards.

Make sure you're unplugged and the mains caps are drained before you start probing around.

Toast

**jpdoe** · 05-08-2009, 02:30 PM

Re: Well, I just joined the club. And the forum! Antec TP 550 EPS died.

Maybe the caps on the PSU filtering the 5vsb output should be replaced.

**PCBONEZ** · 05-08-2009, 08:05 PM

Re: Well, I just joined the club. And the forum! Antec TP 550 EPS died.

There are no FC 10mm with high enough ripple to replace those.
The Fuhjyyu 4700/3300 TM Ripple is around 1580
The Fuhjyyu 1000uF TN Ripple is around 500
The Fuhjyyu 470uf 25v TN Ripple is around 370
The 47uF 35v 6.3mm Fuhjyyu [or Koshin] Ripple is around 110

Use 3300uF 16v and 10v RS series 10mm from BCN [here] for all the 10mm output filter caps [the 4700uF and the 3300uF] and it will do fine.
https://www.badcaps.net/pages.php?vid=22

KC pulled a 4700uF Fuhjyyu from a brand new [unused] PSU and measured it at 3100uF so don't let the label data worry you. It's not really a 4700uF.

From my notes {which might not be perfect} for a complete recap you'll need:
-
4 - 4700uF 10v 10mm [RS 3300uF 10v [or 16v]
2 - 3300uF 16v 10mm [RS 3300uF 16v]
2 - 1000uF 10v 8mm [PW, FC or better]
1 - 470uF 25v 8mm [PW, FC or better]
1 - 47uF 35v 6.3mm [PW, FC or better]
1 - 220uF 16v 6.3mm [Use VZ if can't get better]
1 - 22uF 50v 5mm [PW, FC or better]
2 - 10uF 50v 5mm [PW, FC or better]
1 - 1uF 50v 5mm [KG, PW, FC or better]

The 47uF/35v is sometimes Koshin instead of Fuhjyyu [but replace it anyway] and the 10uF/50v [and some others] might be Teapo which you can leave if you want.
.

**clcorbin** · 05-08-2009, 08:45 PM

Re: Well, I just joined the club. And the forum! Antec TP 550 EPS died.

Originally posted by PCBONEZ

There are no FC 10mm with high enough ripple to replace those.
The Fuhjyyu 4700/3300 TM Ripple is around 1580

Per spec sheet, ripple current of 2200uF FC is 1850mA

Originally posted by PCBONEZ

The Fuhjyyu 1000uF TN Ripple is around 500

FC is 995mA

Originally posted by PCBONEZ

The Fuhjyyu 470uf 25v TN Ripple is around 370

FC is 995mA

Originally posted by PCBONEZ

The 47uF 35v 6.3mm Fuhjyyu [or Koshin] Ripple is around 110

In all, I replaced 9 caps:
4 4700uF 10V
2 3300uF 16V
2 1000uF 10V
1 470uF 25V

Without taking a lot of components out, I don't see how to replace them. Plus, they look good visually (through the 5x magnifier).

The problem right now is I do NOT have the 5V standby voltage (and didn't before replacing the 9 caps either). Here is what I have been able to test and the results:

1) AC power is good. I am getting a steady 120VAC to the rectifier
2) Diodes on rectifier are good and I get the expected diode voltages on each pin pair (single diode or double diodes). The opens are also as expected on a bridge.
3) DC input caps are doing their job. I have 162VDC on each cap. And they do hold their voltage for several hours after removing power unless I bleed it.
4) The diodes at the MOSFET appear to be good.
5) I have a 10khz signal at the gate of the MOSFET from the PWM IC
6) I have a 16usec duty cycle at the gate of the MOSFET
7) With the MOSFET open from the circuit, I can charge the gate with the meter leads (ohm measurement) and then get about 2 ohms drain to source. When I reverse the leads between source and gate (to discharge the gate), then measure the S->D, the resistance goes up to around 48k. It looks like the MOSFET is good.
8) I have 324V at the drain on the MOSFET with the power supply on.
9) The voltage between source and drain with the power supply on is always the drain voltage.
10) Both the primaries and secondaries on the standby transformer (or what I THINK is the standby transformer!) appear to be good (not shorted, not opened. Don't remember the exact ohm)
11) With the supply on, I have 0V on the primary of the standby transformer.

At this point, I am kind of stuck on what else to check. Not having a schematic makes it a lot harder to trace this thing out. Having everything packed in there and buried under the assorted caps and heat sinks doesn't help either!

I also found this thread here. He has the same problem, but there is never anything posted on the final solution (if there was one). I followed several of the troubleshooting tips, but I am definitely at an impasse.

Any ideas folks? It's appreciated!

**PCBONEZ** · 05-08-2009, 11:42 PM

Re: Well, I just joined the club. And the forum! Antec TP 550 EPS died.

There is no 2200uF FC with 1850mA ripple in my data sheet.
Presumably you are looking at the 2200uF 10v 10mm FC that is 1815 for ripple and has ESR of 0.035.

If you don't want ripple in the output and you intend to lower uF by over 1/3 like that you need to lower ESR as well.

The ESR on both the TM's is already less than the 2200uF FC's in 6.3, 10, and 16v.
You would be lowering uF -and- raising ESR. - Not a grand idea for clean DC.

That's why I use the 3300uF RS caps.
The 16v 3300uF has ripple of 3000 and ESR 0.035.
It doesn't say so here but that size is actually custom ordered from the factory specifically to fix PSUs.

FC are fine to replace the TN series.
.

The +5vsb is on a flyback xfmr, it's not through the switcher.
Site glitch a while back pruned a bunch of threads. That old Antec thread used to be longer and as I recall he fixed it but it's been too long and I don't remember how/what did the trick.
.

**kc8adu** · 05-09-2009, 12:10 AM

Re: Well, I just joined the club. And the forum! Antec TP 550 EPS died.

sounds like the +5 stby should be running unless there is a short on the output or the transformer is bad.post pics of the area around the +5 stby.
make sure the rectifier is not shorted.
found that on several cwt built units.

**i4004** · 05-09-2009, 12:19 AM

Re: Well, I just joined the club. And the forum! Antec TP 550 EPS died.

>The +5vsb is on a flyback xfmr, it's not through the switcher.

mhmmm.....bonez i think you're drinking too much....

corbin, what is the chip (or chips) on the primary side of that psu?
and any chips on the secondary side?

if that chip is not supplying that other trafo(that is 5vstby trafo(small one) as you thought) concentrate on other components that might be supplying that trafo, start with lytics....

>5) I have a 10khz signal at the gate of the MOSFET from the PWM IC

this suggests pwm ic is supplied by 300vdc(rectified mains)?

**Toasty** · 05-09-2009, 12:41 AM

Re: Well, I just joined the club. And the forum! Antec TP 550 EPS died.

You'll have to pull the board and trace from the purple wire back across the board to locate the failed component(s). Without a schematic, it's probably the simplest way.

Since you're seeing a 10kHz signal, it likely means the switcher is okay.

In general, you may find 2 or 3 caps in the 5vsb circuit of values ranging from 10uF to the 1000uF ones you did replace. It typically originates on the heatsink closest to the primary caps using the smaller of the 2 transistors/MOSFETs. Be looking for overheating on the board or a cooked resistor nearby. It then runs through a small, maybe 47uF/25v cap, a couple of small diodes and on to the primary of the smaller of the 2 transformers. Output of that goes through a switching diode and those 2 - 1000uF/10v caps with a choke in between them, forming a pi filter, then out to the purple lead.

Again, the 5vsb should be there with the unit just plugged in and PSU power switch on. If you're not using an isolation transformer (you should be), remember that everything on that side is at mains potential and a shock hazard.

Curiosity - How old is this PSU?

Toast

**PCBONEZ** · 05-09-2009, 02:03 AM

Re: Well, I just joined the club. And the forum! Antec TP 550 EPS died.

Did someone hear a ghost?

The 47uF/35v cap is just on the other side of the heatsink from the primary caps and in about the center of the board. [Kind of between the xfmrs.]
One leg is in common with a leg of ONE of the primary caps.
[Not on ground side and not where the two pri caps are connected together.]
The other side [of 47uF/35v cap] connects to a flyback xfmr winding -through- a diode.
The diode-cap connection point is also in common with one leg of a MOSFET.
[A MOSFET - I think, it's heat-shrinked and I'm not cutting it off.]

The two 1000uF 10v form a PI filter for +5vsb output.

The the 220uF is on -12v output.

The 470uF connects between ground and the center leg on a L7912CV that's mounted to the heatsink.
[This one is hard to follow so I say -seems to-.]
Their common point seems to feed through an inductor to one of the toroidal xfmr windings.
.

**i4004** · 05-09-2009, 07:58 AM

Re: Well, I just joined the club. And the forum! Antec TP 550 EPS died.

>Their common point seems to feed through an inductor to one of the toroidal xfmr windings.

bloody hell, it never stops lately.
this psu hosts no toroidal transformer.
ah, i remember...when translated from your language toroidal is usually the coil.
----------------------

rubbish aside, first thing to establish is why there's no 5vstby: is it primary (corbin says there's no voltage on primary, but he mentions some 10khz signal...that's conflicting), is it secondary, or is it transformer itself.

yes, some pictures would help...pictures in the thread bonez linked are too big and too bad....details about the chips used would also help.
tellling us how he measures voltage on 5vstby trafo would also help, etc.etc.

toasty gave a good general direction.

**clcorbin** · 05-09-2009, 11:26 AM

Re: Well, I just joined the club. And the forum! Antec TP 550 EPS died.

Originally posted by PCBONEZ

There is no 2200uF FC with 1850mA ripple in my data sheet.
Presumably you are looking at the 2200uF 10v 10mm FC that is 1815 for ripple and has ESR of 0.035.

You are correct. I translated it incorrectly between one page and another.

Originally posted by PCBONEZ

If you don't want ripple in the output and you intend to lower uF by over 1/3 like that you need to lower ESR as well.

I will be guided by you. Once I get that silly standby power issue fixed, I'll go ahead and replace the two larger caps with more appropriate caps. Thanks for the guidance!
.

Originally posted by PCBONEZ

The +5vsb is on a flyback xfmr, it's not through the switcher.
Site glitch a while back pruned a bunch of threads. That old Antec thread used to be longer and as I recall he fixed it but it's been too long and I don't remember how/what did the trick.

That could explain a few things. I'm definitely NOT an electronics repair expert and not having the schematics to figure out what is going on is definitely kicking me in the head! I was tracing the +5vsb back from the purple lead last night and was not able to track it from the DC side to the AC side of the board. I'll give it more time this weekend.

**clcorbin** · 05-09-2009, 11:42 AM

Re: Well, I just joined the club. And the forum! Antec TP 550 EPS died.

Originally posted by i4004

corbin, what is the chip (or chips) on the primary side of that psu?

The OK I 50 pwm chip
UC3845B (8 pin dip mounted on the top) which appears to be a 5V fixed frequency current mode controller. Not test at this point

Originally posted by i4004

and any chips on the secondary side?

None that I have seen other than what is on the controller board mounted at the edge of the main board

Originally posted by i4004

this suggests pwm ic is supplied by 300vdc(rectified mains)?

- Yes. That chip is an OKI50. A tiny 6 leg chip. I was not able to dig up a datasheet on this guy yet.

There are also three Sharp opto-isolators that straddle the AC-DC line.

**clcorbin** · 05-09-2009, 11:45 AM

Re: Well, I just joined the club. And the forum! Antec TP 550 EPS died.

Originally posted by Toasty

You'll have to pull the board and trace from the purple wire back across the board to locate the failed component(s). Without a schematic, it's probably the simplest way.

Since you're seeing a 10kHz signal, it likely means the switcher is okay.

In general, you may find 2 or 3 caps in the 5vsb circuit of values ranging from 10uF to the 1000uF ones you did replace. It typically originates on the heatsink closest to the primary caps using the smaller of the 2 transistors/MOSFETs. Be looking for overheating on the board or a cooked resistor nearby. It then runs through a small, maybe 47uF/25v cap, a couple of small diodes and on to the primary of the smaller of the 2 transformers. Output of that goes through a switching diode and those 2 - 1000uF/10v caps with a choke in between them, forming a pi filter, then out to the purple lead.

Again, the 5vsb should be there with the unit just plugged in and PSU power switch on. If you're not using an isolation transformer (you should be), remember that everything on that side is at mains potential and a shock hazard.

Curiosity - How old is this PSU?

Toast

It is about 4 years old. I set this server up in 2005. I had to buy a power supply just for the NCCH-DL as it required an EPS supply and I didn't have any in my surplus parts. It has been running pretty much constantly since then with only a little down time for software or hardware upgrades. Even that was pretty seldom.

**PCBONEZ** · 05-09-2009, 12:46 PM

Re: Well, I just joined the club. And the forum! Antec TP 550 EPS died.

.
As does virtually every PC PSU made in the last 25 years this model does indeed use a Toroidal Transformer.
.

Attached Files

**PCBONEZ** · 05-09-2009, 01:00 PM

Re: Well, I just joined the club. And the forum! Antec TP 550 EPS died.

The controller board mounted at the edge of the main board is the fan controler.

The SMPS PWM is an ST UC3845B.
It is at the other end of the heatsink that the 47uF is next to.
https://cdn.badcaps-static.com/pdfs/...d1194df4f1.pdf
.

**i4004** · 05-09-2009, 01:15 PM

Re: Well, I just joined the club. And the forum! Antec TP 550 EPS died.

bonez, that's a coil that's part of output pi filter...
virtully no usual pc psus use toroidal transformers...

that's mostly stuff of exotic audio equipment and alike...

---------------
corbin, uc3845 should be main supply pwm controller, not the 5vstby's....

>None that I have seen other than what is on the controller board mounted at the edge of the main board

if it has some chip there it's probably suppervisor chip that monitors output voltages...or better, as bonez says, just fan control...

3 optoisolators(near the main trafo) are feedback connection for main supply.

so you have 300v being supplied to that oki chip, yet nothing appears on 5vstby trafo(it's the smaller trafo of the two)?
where did you see 10khz signals? they end on mosfet? checked that mosfet?
should be mosfet that supplies 5vstby's primary.

>I was tracing the +5vsb back from the purple lead last night and was not able to track it from the DC side to the AC side of the board.

it goes thru that smaller trafo.
that optocupler near it is the feedback of 5vstby supply.

earlier...
>5) I have a 10khz signal at the gate of the MOSFET from the PWM IC

by pwm ic do you mean oki or uc?
they should both be makinbg pwm pulses, if oki indeed is chip that's making oscillations on primary side of 5vstby trafo..

again, pix would be handy....esp. around 5vstby supply...and that oki chip...

**PCBONEZ** · 05-09-2009, 01:42 PM

Re: Well, I just joined the club. And the forum! Antec TP 550 EPS died.

Despite what it's use is, that coil is a toroidal transformer,,
and one is used there in virtually every PC PSU made in the last 25 years.
i4004's contention that there is no toroidal transformer in the PSU is complete and utter bullshit.

>> uc3845 should be main supply pwm controller <<
"Should be" ?
It is, that's exactly what I said.

Other than the fan controller there is no other controller in it.
Everything else uses regular transistors.
.

**i4004** · 05-09-2009, 01:52 PM

Re: Well, I just joined the club. And the forum! Antec TP 550 EPS died.

>Despite what it's use is, that coil is a toroidal transformer,,

transformers transform...what is this coil transforming?
which voltage to which other voltage?

god you can be dense. if bonez repeats something enough times it becomes true?
nope. no toroidal trafos in psus. toroid coils, yes.
word toroid just denotes the shape.
http://www.merriam-webster.com/dictionary/toroid
or
http://www.answers.com/topic/toroid

learn your language, learn electronics basics.

http://images.google.com/images?q=to...N&hl=en&tab=wi

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