Opinion about PSU (after recap)

[momaka]

Re: Opinion about PSU (after recap)

Well, it's fine then. I've got a Rubycon MBZ, a Nichicon HD along with 3 UCC KY caps.

Well, the ESR is not as important sometimes as the capacitance is. Just keep in mind that while the PSU can still work fine with ultra-low ESR caps, the ripple output may be higher due to small oscillations produced by the LC filter output due to the ultra-low ESR.

In general, I suggest two caps of at least 1500 uF caps on the 3.3V rail, same for the 5V rail, and one cap with at least 1500 uF on the 12V rail (but two caps of at least 1000 uF would be better).

Yes,maybe L&C are crap. But for a 90W TDP Northwood,I'm pretty sure it won't die.

It won't die, but if the output filters aren't up to snuff, you can get an unstable computer (I've had an L&C do that). That's why I stress it's so important to make sure that all of the output PI coils are there. With the two 1500 uF 16V caps on the output, I think that would be enough for the capacitance on the 12V rail (well, assuming you will be using those on the 12V rail).

The other thing you need to check is the 12V rectifier since your motherboard does appear to have a P4 12V connector (which means the CPU will be pulling its power from the 12V rail). I suggest a 16A or 20A rectifier rated for 100V or higher (usually something like a STPR1620CT or STPR2010CT since they are most common). Do NOT use 40V or 45V schottky diodes on the 12V rail (i.e. STPR2045CT) - they may not be able to take the high reverse voltage spikes.

A 10A or 12A rectifier will likely run hot. Unfortunately, this is what is most common in L&C PSUs on the output of the 12V rail.

[Dan81]

Re: Opinion about PSU (after recap)

It won't die, but if the output filters aren't up to snuff, you can get an unstable computer (I've had an L&C do that). That's why I stress it's so important to make sure that all of the output PI coils are there. With the two 1500 uF 16V caps on the output, I think that would be enough for the capacitance on the 12V rail (well, assuming you will be using those on the 12V rail).

Well,good idea. I think I'm going to use a few 1200 16V in the 3.3 and 5V places (I assume there isn't going to be a problem using them in those places) and use the 1500uF UCC KY caps in the 12V section. Guess it should do the job,the 1200s are Rubycon ZL btw.

[goodpsusearch]

Re: Opinion about PSU (after recap)

If the pcb has space for only 1 capacitor for 12V output filter you shouldn't go lower than 1x2200uF 16V. It would be also a bad idea to use general purpose capacitors.

[Dan81]

Re: Opinion about PSU (after recap)

Just got the PSU.

Lo and behold,it's somewhat decent:

-ERL-35 transformer
-heatsinks are quite wimpy
-Saturn (YC) primary caps - might replace those with Seacon caps.
-weird component near fan that looks like a transformer,all it's written on it is LF1250CD00
-2 damn big output coils
-Saturn (YC) secondary caps - all look fine.
-22-20AWG wire
-2005Z PWM chip
-Saturn fan (seriously Deer...) - been replaced with another one.
-EMI filtering - did Deer ever use this on older units?
-no bridge rectifier

Caps look new,so no need to replace for now. I however need to replace the AC plug,since this one is so solid there's no current flowing in it o.O .

BTW,my mistake on the model : it isn't LC-B400ATX. It's LC-C400ATX.

[Dan81]

Re: Opinion about PSU (after recap)

Another update:

Turns out that the Premier was dead. Had to install a recapped board that was working. Here's the UL number if you want to search it - E231151.

The original PSU I took the working PCB from said "BURN-IN OK"...it really is true:
- the PSU not only had a seized fan,the PCB was brown (and real black underneath a resistor)

-the caps were - YongXing VZ primaries (fake Nichicon VZs) and bulging ChengX caps on the secondary side.

Replacements to make it work fine (it's gonna power a 90w Northwood PC) for the caps:
-YongXing VZ - Seacon primaries - 330uf 200v
-bulging ChengX 1500uf 10v and one 470uf 10v - Saturn (YC) caps 1000uf 10V.

Just for laughs, the PSU I took from the PCB just said - Switching Power Supply ATX-450W

Good thing though,the heatsinks look decent. Also,it has 2 SATA plugs and a 20+4 pin ATX cable. Soldering on the underside was better than Deer or Sun Pro.

PS: Board discoloration?I don't care as long as it's not going to

[CapSwapper]

Re: Opinion about PSU (after recap)

if you want to recap you need a good foundation to build from. recapping a junk PSU is like polishing a turd. all the other components could either be junk or fakes. IMO I would throw all those PSU's in a dumpster rather than plugging them into my Z97 and X99 motherboards

[Th3_uN1Qu3]

Re: Opinion about PSU (after recap)

Agree 100% with the above. I just had one of those Delux PSUs with the green label blow up, taking the motherboard with it.

I had just fixed that motherboard (shorted VRM), and the owner said he tested the PSU in another computer and it worked, it's just the motherboard that doesn't power up. I had tested the PSU with no load and all voltages were in spec. But when i attempted to power up the repaired mobo with this PSU, it ran for a few seconds then kaboom.

It killed the VRM again. After repairing it a second time and testing with another PSU, the board now does absolutely nothing when the power button is pressed. I honestly thought the PSU had turned off because the fan stopped, and it exploded just as i reached for the power cord to unplug it and test with another one. I know the failure mode of that PSU, if it loses the 12v rail there is no protection and the combined feedback will attempt to keep the voltage close to the reference, which means 5v and 3.3v will skyrocket before the thing blows up. So i'm quite sure that nForce 4 SLI chipset is now in heaven.

This is an old socket 939 system so no biggie, but that's still wasted time for what would have otherwise been easy money.

Some people just don't believe these stories until it happens to them. Either way, if this PSU hadn't blown now, it would have killed the system later and i would've been blamed for it, so it's better this way.

[CapSwapper]

Re: Opinion about PSU (after recap)

we're in a new era of junk PSU's. companies will do whatever it takes to make a profit. I don't trust any of them. I'd rather void the warranty than have it blow up a brand new motherboard. I take apart every new PSU and change out all the junk caps and inspect everything then test it for at least 24 hours. 10 years ago a PSU blew up my motherboard and took the CPU with it

[Dan81]

Re: Opinion about PSU (after recap)

Agree 100% with the above. I just had one of those Delux PSUs with the green label blow up, taking the motherboard with it.

I had just fixed that motherboard (shorted VRM), and the owner said he tested the PSU in another computer and it worked, it's just the motherboard that doesn't power up. I had tested the PSU with no load and all voltages were in spec. But when i attempted to power up the repaired mobo with this PSU, it ran for a few seconds then kaboom.

It killed the VRM again. After repairing it a second time and testing with another PSU, the board now does absolutely nothing when the power button is pressed. I honestly thought the PSU had turned off because the fan stopped, and it exploded just as i reached for the power cord to unplug it and test with another one. I know the failure mode of that PSU, if it loses the 12v rail there is no protection and the combined feedback will attempt to keep the voltage close to the reference, which means 5v and 3.3v will skyrocket before the thing blows up. So i'm quite sure that nForce 4 SLI chipset is now in heaven.

This is an old socket 939 system so no biggie, but that's still wasted time for what would have otherwise been easy money.

Some people just don't believe these stories until it happens to them. Either way, if this PSU hadn't blown now, it would have killed the system later and i would've been blamed for it, so it's better this way.

Seems I had luck with my Codegen "450W"....due to bad soldering (from me of course..)one of the neutral wires desoldered and a loud bang.

Nothing looked out of the ordinary on the PSU PCB. I replaced it with another AC plug that has some filtering on it (it came from a gutted Delta PSU that was too weak) but I've yet to power it on.

Weird thing,it took NOTHING with it. Tested board,HDD and all parts with a good Delux PSU (with almost 7 years of daily use) and all were fine.

CapSwapper - It's not going to power a X99 or such system. I use it with a old Pentium 4 board with the P4M800 chipset