Annoying heavy load-failure in Tecnoware Free Silent 500W

[omega]

Hello all, this is my first post here, so please be clement.
The machine I am mantaining is a Intel Q6600 QuadCore/based and is equipped with a Tecnoware 500W SMPS Cod. FAL501FS12. It has been working on heavy load (four physical HDDs) 24h/365d. That PSU usually works good for few months, then my machine invariably begins to undergo some serious ATAPI errors to their HDDs, that's IMHO a sign of some failure in the +12 PSU line. However on my inspection, the PSU seems good, I have been checking all secondary caps and the are good both in shape and in ESR (as checked with Blue ESR Meter). The PSU is still indeed good for normal duties, but for intensive job has to be replaced. This happened few times in the last few years.
My question: according to your knowledge, what do you advise me to check to find the culprit compontent(s) (if any) to repair? In other words, how to approach the troubleshooting of this annoying intermittent failure?
I think your hints may be useful to other amateur PSU servicers.
Your attention and possible help is greatly appreciated.

[momaka]

Re: Annoying heavy load-failure in Tecnoware Free Silent 500W

Welcome, omega!

what do you advise me to check to find the culprit compontent(s) (if any) to repair? In other words, how to approach the troubleshooting of this annoying intermittent failure?

Unfortunately, there isn't much you can repair in this power supply. The PSU you have there is a "cheapo" one... in other words, very low quality. The output caps may appear good, but that's not the problem. The problem is they are too small to "clean" the power that comes out of this PSU. And even if you did install the proper size capacitors, the board layout in this PSU does not have space for output PI coils (inductors). That means the components in your PC will be fed with dirty power... i.e. unstable voltages with many spikes. This is precisely why you are getting HDD-related errors. If you leave this PSU in your system, I guarantee it will make your HDDs fail very soon.

Also, the "500W" rating is absolutely fake! At most, this power supply will give you 200 Watts raw power.

The solution I suggest to you is to NOT use this PSU.

You can try to fix it as a learning experience (and we will gladly help you with that). But please do NOT use it in a computer that is important to you (or anyone else), because these cheap low quality PSUs are well known to blow up and kill other PC components with them.

Here are some examples of what GOOD power supplies look like:
https://www.badcaps.net/forum/showthread.php?t=7335

[goodpsusearch]

Re: Annoying heavy load-failure in Tecnoware Free Silent 500W

I completely agree with momaka

[goontron]

Re: Annoying heavy load-failure in Tecnoware Free Silent 500W

Another one with momaka... Scrap it!

[kaboom]

Re: Annoying heavy load-failure in Tecnoware Free Silent 500W

Welcome, omega!


Unfortunately, there isn't much you can repair in this power supply. The PSU you have there is a "cheapo" one... in other words, very low quality. The output caps may appear good, but that's not the problem. The problem is they are too small to "clean" the power that comes out of this PSU. And even if you did install the proper size capacitors, the board layout in this PSU does not have space for output PI coils (inductors). That means the components in your PC will be fed with dirty power... i.e. unstable voltages with many spikes. This is precisely why you are getting HDD-related errors. If you leave this PSU in your system, I guarantee it will make your HDDs fail very soon.

If they haven't been damaged already...

Also, the "500W" rating is absolutely fake! At most, this power supply will give you 200 Watts raw power.

The solution I suggest to you is to NOT use this PSU.

The "500W" rating is made up, as usual. And no matter the load, you can bet on it being "raw power." You made a funny and didn't even realize it!

Even at 500mW out, you'll be getting more AC than DC.

You can try to fix it...

...by crushing it under your feet!

Been there, done that.

[omega]

Re: Annoying heavy load-failure in Tecnoware Free Silent 500W

Thanks so much for all your answers! I already wrote that at the beginning, this PSU has been working excellent, therefore something has been slightly failing in somewhat with time!
Anyway, the point is: I have few more such spare PSUs, but no money to buy others (research budget is so low in South Italy!).
So I have to choose ether to repair them or stopping researching and perish
So please forgive me when I insist to ask how to fix it

[goodpsusearch]

Re: Annoying heavy load-failure in Tecnoware Free Silent 500W

You can easily find another psu for free that will be worth repairing. Recycling centers and PC shops are full of them. There are also for sale on ebay or else for ~5 euros.

[omega]

Re: Annoying heavy load-failure in Tecnoware Free Silent 500W

You can easily find another psu for free that will be worth repairing. Recycling centers and PC shops are full of them. There are also for sale on ebay or else for ~5 euros.

I have to care 18 such machines :-(

[momaka]

Re: Annoying heavy load-failure in Tecnoware Free Silent 500W

I already wrote that at the beginning, this PSU has been working excellent, therefore something has been slightly failing in somewhat with time!

It may appear like it was "working excellent", but the truth is, such low quality PSUs *never* do. The problem is that you don't see anything wrong on the surface. But the lifetime of the HDD and other system components is greatly reduced, which is why you got those "ATAPI errors". And the more you use these PSUs, the more "errors" and "bugs" will appear. You will get to a point where you will be pulling your hair all the time, because of all of the problems these PSUs will cause eventually.

Anyway, the point is: I have few more such spare PSUs, but no money to buy others (research budget is so low in South Italy!).
So I have to choose ether to repair them or stopping researching and perish
So please forgive me when I insist to ask how to fix it

No need to be sorry here.

If you really have no other option but to fix these power supplies, we will help you, because any kind of fix or "upgrade" on these PSUs would be better than using them the way they are right now.

However, let me just warn you that the parts for these PSUs may cost almost as much as buying a used PSU.

At a minimum, you will need:
* four (4) 6.3V or 10V, 2200 uF capacitors
* two (2) 16V or 25V, 1500 uF capacitors
* two (1) 6.3V or 10V, 1000 uF capacitor
* one (1) 16V or 25V, 470 uF capacitor
* one (1) 20 Amp, 60-100V schottky rectifier (TO-220 or TO-247, 3-pin with common-cathode)
* two (2) 50V, 1-10 uF capacitors (will tell you specifically when I see more pictures of the PSU)
* one (1) 50V, 1-47 uF capacitor (will tell you specifically when I see more pictures of the PSU)

^ These are all of the parts for one (1) power supply. Also, if you want your repair to last, you should use only quality Japanese capacitors. That means avoiding eBay (especially sellers from China). And even then, the fixed power supply still won't be decent by a long shot. But those parts may be just enough to keep the PC alive and not crash.

Also, I would suggest adding more pictures here so we can see exactly what we are working with (preferably, one picture of each side of the PSU). And if you can, give us the part numbers you see on the parts mounted on the heatsinks (radiators). I actually have an idea of what they will be, but would just like for you to confirm. (Probably 13007 NPN BJTs for the main PS with 10-15 Amp schottkies for the 3.3V and 5V rails, and 10 Amp or *maybe* 12 Amp FR rectifier for the 12V rail. 5VSB probably standard 2-transistor motherboard killer design.)

I have to care 18 such machines :-(

Ouch!
Do they ALL use this same exact PSU?!

If that's the case, I think you might be better off finding a few used but *good quality* power supplies for cheap and fixing only a few of those machines than spending all of the money on parts to fix these cheaper power supplies. But I will wait for your response.

And no matter the load, you can bet on it being "raw power." You made a funny and didn't even realize it!

Hehe. Nope, wasn't trying to be funny at all here .
Whenever dealing with low-quality PSUs, I always try to refer to the output power as being RAW, precisely because of all of the ripple and noise.

...by crushing it under your feet!

Believe it or not, I've never done that. Even the cheapest and most low-quality PSUs still have at least a few parts worthwhile of taking.
I actually had a super-gutless wonder PSU that helped me save at least two other PSUs (one of them was a good quality HiPro, the other a 105W, 12V halogen light converter), a CRT monitor, and a few other things I can't remember without digging a bit in my "repair" gallery. Also was a good source of parts for my college projects. And best of all, it was an excellent lesson to further improve my desoldering skills (this was back when I joined BCN).

So yes, I have respect even for the worst PSUs.

[omega]

Re: Annoying heavy load-failure in Tecnoware Free Silent 500W

Dear momaka,
thanks so much for your support and sorry for the delay in answering you.
Your last message has been very impressive to me!
I have been taking some pics of the PSU and will be posting in a short time.
The semiconductors on the radiators are following:
hot side: one C5027 and two KSH13009
secondary side: one F16C20CT and two SBL2040CT.
Therefore if I am right, there are one 16A and two 20A Schottky diodes, that's slight better than you have foreseen.
The PWM chip is a China one (SDC 2921).
As regards caps, they all are China quality (ChengX), but I had to count only 4x 1500 uF/10 V, 2x 1500 uF/16 V, 1x 470 uF/16 V, 2x 47 uF/50 V, 2x 1 uF/50 V (11 caps) in the secondary side (so no 2200 uF cap).
I still got troubles in finding in my town japanese quality caps, but i will try requesting them in North Italy once we will be arranging a complete list of them.
Ready to give you other pieces of info at your request!
Best regards

[momaka]

Re: Annoying heavy load-failure in Tecnoware Free Silent 500W

You are welcome

hot side: one C5027 and two KSH13009

A little better than I expected - at least the two KSH13009, that is. They are slightly better than the standard 13007's used in cheap power supplies. With those, your PSU may be able to handle up to 300-350 Watts if the rest of it is designed right, which should be enough for a Core 2 Quad CPU. I also see the big 200V capacitors on the hot side are 560 uF, which is good.

Now do the computers you are working on have a dedicated graphics card in the PCI-E slot?

secondary side: one F16C20CT and two SBL2040CT.
Therefore if I am right, there are one 16A and two 20A Schottky diodes, that's slight better than you have foreseen.

Indeed.
The two SBL2040CT schottky diodes are okay - they are for the 3.3V and 5V rails, which are not used much in modern PC. So you don't need to worry about these.

The F16C20CT is what needs to be upgraded, because this is what is used for the 12V rail. Ideally, you should buy a schottky-type rectifier rated for at least 60V and 20 Amps or more. Something like STPS20S100CT, MBR40L60CT, or MBR2060CT would work great (there are many more choices, though). Again, look for schottky -type rectifiers only. The F16C20CT is a fast recovery -type rectifier and has a much higher voltage drop, which means higher losses in the PSU, more heat, and lower output voltages (not desirable).

As regards caps, they all are China quality (ChengX), but I had to count only 4x 1500 uF/10 V, 2x 1500 uF/16 V, 1x 470 uF/16 V, 2x 47 uF/50 V, 2x 1 uF/50 V (11 caps) in the secondary side (so no 2200 uF cap).

Well, the capacities are not as bad as I expected either. But still, you should consider getting the 2200 uF and 1500 uF capacitors I mentioned in my last post.

I still got troubles in finding in my town japanese quality caps, but i will try requesting them in North Italy once we will be arranging a complete list of them.

You would probably need to get your capacitors online from a reputable seller.
I think RS Components, Farnell/Element 14, and Newark are some of the online joints that serve Europe. You may also contact member Behemot here - he sells caps too, and he is based in Czech Republic. If you do contact him, ask if he still has the 10 mm Samxon RS 16v 3300 uF, as those would be ideal for the 12V rail of your PSUs. If not, I think he has some Chemicon 16V 2200 uF caps in 10 mm diameter as well.

Ready to give you other pieces of info at your request!

Please do.
It will really help to find what else might need to be modified or upgraded in this power supply to make it run safer/better.

[Behemot]

Re: Annoying heavy load-failure in Tecnoware Free Silent 500W

Yeah if you need some caps I can provide you, just got some new, all dirty cheap…much more than from those big ass resellers.

If you'll need some beefier silicon or bigger second-hand 200V caps, Pi coils, I should have lots of those from disposed PSUs…I would suggest, if there are parallel positions, to use two of those F16C20CT rectifiers instead of single schottky. Because single schottky could bring the voltage too much higher which will make problems with regulation…with two rectifiers, if both are really same, you should be able to get about 250 W fine with still better efficiency tha before…

[Th3_uN1Qu3]

Re: Annoying heavy load-failure in Tecnoware Free Silent 500W

That is an old, 3.3/5v heavy design running a new, 12v-heavy computer. If anything, the 12v rail will be very low. Replacing the fast recovery diode with a schottky will be no problem, and is actually recommended.

[omega]

Re: Annoying heavy load-failure in Tecnoware Free Silent 500W

Here the HR pics of the PSU you requested me.
Some years ago, I have assembled a computer rack with 15 among Dual Core Duo/Quad machines (44 cores). Mobos have been anyway Asus P5B "Vanilla", and the machines have been equipped with four 2GB DDR3 banks, one physical SATA HDD 7200 rpm for each core, one DVD burner and one 3.5'' disk drive. Since they had to do MPI numerical computation only, graphic cards (in the PCIEX16 slot) were unimportant and cheap (ASUS EN-6200-LE).
Then I choose robust, double fan Tecnoware FAL500DF2 500W PSUs (I will show it in a next post to try to convince you it was a good example of entry level PSU), but with time, those PSU had been failed and had to replace them, blind trusting in the brand and not noticing that in the meanwhile production has been transferred to China and the quality, including weight, had been reduced (FAL501FS12). For isntance, cap-sized inductors in the secondary circuit have disappeared from the PSU. But when I realised it, it was too late to come back.
Anyway, the modification you are proposing me is the replacement of the TO220 12V rail double diode (sorry no parallel positions), and the caps with those of bigger capacity. Right? But I still don't understand what cap should replace what.
I still wait for you in order to arrange a definitive improvement project to buy the components.

[omega]

Re: Annoying heavy load-failure in Tecnoware Free Silent 500W

For your reference, here are the four side pics of the old Tecnoware FAL500DF2. Moreover, what you cannot see in the pics: 2x SC2625 as choppers and 2x S30D40C + 1x SF2004PT as double diodes.
In 2010 I dismissed many of them, in retrospective I think it was unwise not to repair instead of replacing them with new wares. But everyone has to learn based on his/her own errors.

[momaka]

Re: Annoying heavy load-failure in Tecnoware Free Silent 500W

I would suggest, if there are parallel positions, to use two of those F16C20CT rectifiers instead of single schottky. Because single schottky could bring the voltage too much higher which will make problems with regulation…

In my experience, a single schottky diode will usually have about the same or lower voltage drop (Vf) than two fast recovery rectifiers in parallel, so I think it would be a lot better to use the schottky. It does depend a lot on what schottky you get, though. Some have large forward voltage drop - almost as much as the FRs. The three schottky rectifiers I suggested are decent, especially the MBR40L60CT, which will have about 0.5V Vf at 10 A per diode leg - IMO, that's quite an improvement over the F16C20CT. Even the STPS20S100CT will have about 0.6V Vf at 10 A. Compare that to two F16C20CT in parallel, which will still have about 0.85V Vf each at 5 A per diode leg.

Anyway, the modification you are proposing me is the replacement of the TO220 12V rail double diode (sorry no parallel positions), and the caps with those of bigger capacity. Right?

Yes, exactly!

Here the HR pics of the PSU you requested me.

Excellent pictures! I think that will do for now. However, a picture of the underside (solder side) and another of the secondary side caps from up top could help too. I think there may be large "dummy" load resistors on the secondary of your PSU, and those like to run very hot sometimes (but it depends on what the PSU manufacturer chose). If they do run hot, it may be a good idea to remove them. I do that with my Deer/L&C PSUs all the time, because the hot dummy load resistors in those cook the caps.

But I still don't understand what cap should replace what.

See edited picture I attached:
https://www.badcaps.net/forum/attach...9&d=1451272098

* The caps with purple dots are for 5 VSB. Use two (2x) 1000 uF 6.3/10V caps with 8 mm diameter.
* The caps with orange dots are for 3.3 V rail. Use two (2x) 2200-3300 uF 6.3/10V caps with 10 mm diameter.
* The caps with red dots are for 5 V rail. Use two (2x) 2200-3300 uF 6.3/10V caps with 10 mm diameter.
* The caps with yellow dots are for 12 V rail. Use two (2x) 1500-3300 uF 16V caps with 10 mm diameter.
* The cap with blue dot (hidden behind 12V rail caps) is for -12 V rail. Use one (1x) 470-1000 uF 16V cap here.
* The caps with green dots are for BJT (chopper transistors) drive circuit. Use same voltage and capacitance as originals. Just make sure they are of high quality, like the caps above.

I don't see a "critical" 5 VSB cap on the primary side, so that is good. However, the caps around the PWM controller (SDC 2921) may be important too (I labeled them with Cyan dots). I see only four of them, so why not replace them anyways - especially the one with the double cyan dots.

With those caps and the new 12V rectifier, I think the PSU should be fairly decent for a C2Q system. Hopefully the "Rumlcon" caps on the primary are not too bad, because with that name, I can only assume they are Rubycon look-alikes.

Finally, make sure the PSU fan is NOT wired directly to 12V, because cheap PSUs often use cheap fans that like to die quickly when wired to 12V directly (which happens in at least 90% of cheap PSUs). There are a few different ways to lower the voltage on the fans, but I will wait until you post a picture of the bottom side and the secondary side from up top to see what is there.

Mobos have been anyway Asus P5B "Vanilla", and the machines have been equipped with four 2GB DDR3 banks, one physical SATA HDD 7200 rpm for each core, one DVD burner and one 3.5'' disk drive. Since they had to do MPI numerical computation only, graphic cards (in the PCIEX16 slot) were unimportant and cheap (ASUS EN-6200-LE).

Be careful with those ASUS items.

Both the motherboards and the video cards may have Chemicon KZG caps (brown caps with a "Y" vent on top). The KZG series from Chemicon is know to fail quite A LOT, especially with high heat. I suggest you inspect all motherboards and video cards.

Better yet, if you want piece of mind, it might be worthwhile to replace those KZG caps too, while you are at it. Now, I know I keep adding things for you to do - sorry for that. But I just really want to make sure you are aware of what you are dealing with, in case more issues appear in the future, be it from the motherboards or the graphics cards. Speaking of the graphics cards, the EN-6200-LE appear to be a passively-cooled. If you do ever get a PC with a "no video output" problem, the graphics card could well be the issue. Reason being is that the GeForce 6x00 series tend to break much faster when heated above 60C, and with a passive radiator, those EN-6200-LE cards may be reaching that temperature.

For your reference, here are the four side pics of the old Tecnoware FAL500DF2. Moreover, what you cannot see in the pics: 2x SC2625 as choppers and 2x S30D40C + 1x SF2004PT as double diodes.
In 2010 I dismissed many of them, in retrospective I think it was unwise not to repair instead of replacing them with new wares. But everyone has to learn based on his/her own errors.

Yup, those older FAL500DF2 units were indeed much better built. Looks like CWT with those green transformers, but I could be wrong.

Do you still have all of those broken FAL500DF2 PSUs? - at least the boards (I am assuming you do, since you did take a picture of it). If yes, it may be worthwhile to try and repair some of these and place them in the cases of the of the FAL501FS12 units. I am looking at the pictures, and they look a lot more promising.

[Behemot]

Re: Annoying heavy load-failure in Tecnoware Free Silent 500W

In my experience, a single schottky diode will usually have about the same or lower voltage drop (Vf) than two fast recovery rectifiers in parallel

That's exactly my point. If you add half a volt, it may be OK under heavier +12 V load, but in idle the unit may get crazy because it will be too much for the feedback…

[omega]

Re: Annoying heavy load-failure in Tecnoware Free Silent 500W

I attached the pics you requested, including that of the fan and the specifications in the case of the PSU for your reference. In the first pic you can also see the black wires of sort of sensor which lies inside the right coil.

However, a picture of the underside (solder side) and another of the secondary side caps from up top could help too. I think there may be large "dummy" load resistors on the secondary of your PSU, and those like to run very hot sometimes (but it depends on what the PSU manufacturer chose). If they do run hot, it may be a good idea to remove them. I do that with my Deer/L&C PSUs all the time, because the hot dummy load resistors in those cook the caps.

In facts, between the two coils (see pic) there are two uncommon 1W resistors, that's 110 [?] and 51 [?] ohm, respectively (the latter is invisible in the pic). There is a slot in in the PCB in correspondence of the two resistors (to dissipate heat?), so I guess these are load ones, right?

See edited picture I attached:

That's fine, thanks. I am beginning to understand better the meanings of the different rails.

Finally, make sure the PSU fan is NOT wired directly to 12V, because cheap PSUs often use cheap fans that like to die quickly when wired to 12V directly (which happens in at least 90% of cheap PSUs). There are a few different ways to lower the voltage on the fans, but I will wait until you post a picture of the bottom side and the secondary side from up top to see what is there.

Sorry I don't understand what you mean. One 12 cm 12 V brushless fan (see pic) is plugged in the socket in the right bottom of the cap pic.

Be careful with those ASUS items.

You are right! Over these years I experienced lots of Chemicon KZG 6.3 V 820 uF cap failures, most of which have been in the southbridge. By replacing them with Panasonic good ones, I saved all mobos except two. Failures also in the graphic card (same damn cap) have been fixed. Incidentally, replacing those caps has been the divide between my passive (i.e. user) and active (i.e. amateur fixer) use of the machines.
But I did not replace all caps, just wait some get bulged and replace them.

Do you still have all of those broken FAL500DF2 PSUs? - at least the boards (I am assuming you do, since you did take a picture of it). If yes, it may be worthwhile to try and repair some of these and place them in the cases of the of the FAL501FS12 units. I am looking at the pictures, and they look a lot more promising.

Yes I get a box full. But as you saw, unfortunately I have cut all wires and disposed all the cases and restoring them now maybe would be not worth of.

[Behemot]

Re: Annoying heavy load-failure in Tecnoware Free Silent 500W

You can at least take the silicon from them and upgrade the others ones with it…

[omega]

Re: Annoying heavy load-failure in Tecnoware Free Silent 500W

In choosing Nichicon caps on RS, I discovered that there no apparent indication of ESR value. On the other hand, lifetime at 105 °C is indicated. I do hope 1000-2000 hours is not too little.

You can at least take the silicon from them and upgrade the others ones with it…

That's not feasible, because old diodes are much bigger and different pitch