Intermittent power on - P4PB-400 w/ FSP350-60BN PS

[johnmeyer]

Symptom: If computer is unplugged from the wall outlet for 15 minutes, and then plugged in, I can press the "on" button and the computer starts and runs for as long as I want. But, if I power down, but keep the computer plugged in, when I later press the "on" button, nothing happens. However, sometimes if I press the on button 15-20 times, the computer eventually starts.

System components: Motherboard: ASUS P4PB-400. P/S: Sparkle FSP350-60BN.

First fix attempt: The seven 2200uF 6.3V caps (GSC) on MB were leaking. Replaced them with good, low-ESR caps, but problem remains. (Old caps measured <1000uF after removal, so they were definitely ailing, although still somewhat functional).

I am reluctant to continue to re-cap the MB for two reasons: (1) It was a PIA to desolder the ground side of the caps because of the huge ground plane they are attached to. Even with a physically large 800W tip in my Weller soldering station iron, I couldn't get enough heat to flow and wick the solder.

(2) But, the main reason I don't want to continue, and now want to replace or repair the PS (and why I'm posting here): I have twice had this exact same problem in another, newer computer which had Sparkle power supplies, and both times the problem was fixed simply by replacing the PS.

So, two questions:

(1) Which caps on this Sparkle (FSP) power supply might affect the ability of the MB "on switch" to actually turn on the computer?

(2) Can anyone recommend a reasonable 350W or greater PS that I can purchase as a replacement? This is a 150mm x 86mm x 140mm form factor and has a 20-pin MB connector along with a 4-pin CPU connector.

Many thanks for any help!

John

[Pentium4]

Re: Intermittent power on - P4PB-400 w/ FSP350-60BN PS

I would check the 5VSB caps on the FSP supply, I have seen many of these fail in this exact model. Since they're usually Teapo or CapXon they don't tend to last that long on the 5VSB

[mockingbird]

Re: Intermittent power on - P4PB-400 w/ FSP350-60BN PS

Which caps did you use in place of the original ones?

Regarding the PSU -- does your motherboard actually need the -5v rail? If not, the Seasonic SSR-360GP PSU is a pretty good replacement.

[johnmeyer]

Re: Intermittent power on - P4PB-400 w/ FSP350-60BN PS

I would check the 5VSB caps on the FSP supply ...

I'm trying to locate these on my PSU:



Based on your advice, I've been searching other posts re: 5VSB problems, and your diagnosis seems to match exactly the problem I'm having.

None of the caps in my PS is bulging, so I'm going to have to locate based on getting a schematic or obtaining some advice. I really don't want to re-cap the whole supply, if I can avoid it.

Which caps did you use in place of the original ones?

You are asking about the mobo caps. I used these (from Digi-Key):

Nichicon HM series 2200uF 6.3V 10x16mm, 18 mOhm impedance

the Seasonic SSR-360GP PSU is a pretty good replacement.

I'll look at that. If I can't re-cap, I'm leaning towards this one: StarTech ATX2POWER350 350 Watt ATX12V

[Pentium4]

Re: Intermittent power on - P4PB-400 w/ FSP350-60BN PS

The main 5VSB caps should be hidden under that heatsink on the left from your picture. That StarTech is probably an older ATNG unit. It would probably work fine but most likely also has poor quality capacitors in it (and it's a little pricy for what you get) I would go with the one mockingbird suggested I think it's worth the extra cash and will outlive the system and you could use it for a newer build later

[johnmeyer]

Re: Intermittent power on - P4PB-400 w/ FSP350-60BN PS

The main 5VSB caps should be hidden under that heatsink on the left from your picture. That StarTech is probably an older ATNG unit. It would probably work fine but most likely also has poor quality capacitors in it (and it's a little pricy for what you get) I would go with the one mockingbird suggested ...

Thanks for the very quick reply.

There are three caps under that heatsink, or in the vicinity (all SEK 105C): 470 uF 16V; 47uF 35V; and one that can't be read without removal because its labeling is touching the heatsink. None of these values is what I'd expect for a 5V circuit

As for using the Seasonic PSU recommended by Mockingbird, it has a fan configuration that doesn't fit my case (the Sparkle FSB350-BN has fan facing the rear -- click this link: FSP350-60BN), and it has lots of SATA connectors which are useless on this older computer, and therefore will require adapters.

This is no longer a 24/7 computer and is already been in service for a decade, so I can live with slightly shorter lifetime of the Startech ... the Sparkle may have bad capacitors, but it ran almost 24/7 for six years, and then another four years beyond that in intermittent service.

I'm still looking through other posts on these forums to see if I can positively identify which caps to replace. If I strike out, I'll give up on the re-cap of the PSU, and simply replace it.

Many thanks for the help.

[johnmeyer]

Re: Intermittent power on - P4PB-400 w/ FSP350-60BN PS

Quick P.S. to last post: I opened my main PC to look at the PSU, and the fan faces the interior of the case, so I guess I could do the same thing with this PSU.

[cheapie]

Re: Intermittent power on - P4PB-400 w/ FSP350-60BN PS

You could just wire up a "wall wart" style power supply externally for the +5VSB (switching type, NOT linear). Or, for ultimate ridiculousness, wire it up off of the USB port of another computer...

[mockingbird]

Re: Intermittent power on - P4PB-400 w/ FSP350-60BN PS

None of the caps in my PS is bulging, so I'm going to have to locate based on getting a schematic or obtaining some advice. I really don't want to re-cap the whole supply, if I can avoid it.

The only way to know for sure would be to measure the Teapo SEK. Also, the secondary filtering caps are not all Teapo.

You are asking about the mobo caps. I used these (from Digi-Key):

Nichicon HM series 2200uF 6.3V 10x16mm, 18 mOhm impedance

Nichicon HM are good, but please be aware for the future that there is also a 10x20 version the cap which is superior. Also, the re-cap may not be complete since you did not replace these other caps:



I assume that you replaced a total of only 10 caps, and that those that I have not indicated were not replaced.

I'll look at that. If I can't re-cap, I'm leaning towards this one: StarTech ATX2POWER350 350 Watt ATX12V

Startech is absolute trash. If you must buy a Taiwanese PSUs, I would go with FSP (Sparkle) or InWin.

As for using the Seasonic PSU recommended by Mockingbird, it has a fan configuration that doesn't fit my case (the Sparkle FSB350-BN has fan facing the rear -- click this link: FSP350-60BN), and it has lots of SATA connectors which are useless on this older computer, and therefore will require adapters.

Quick P.S. to last post: I opened my main PC to look at the PSU, and the fan faces the interior of the case, so I guess I could do the same thing with this PSU.

Correct. What you mean to say is that the fan is on the bottom of the PSU rather than on the back. This is normal when they use 120mm fans. The exhaust is still on the back. FSP's newer PSUs almost always have this fan configuration as well.

I know it has lots of SATA cables you don't need, but it is a very reliable PSU and will last you through many upgrades.

[johnmeyer]

Re: Intermittent power on - P4PB-400 w/ FSP350-60BN PS

Also, the re-cap may not be complete since you did not replace these other caps

I am well aware of that, but it took me about four hours to replace the seven caps (it was seven on my mobo, not ten) because of the problem I mentioned earlier. I've never had that problem before (of having a ground plane act as a heat sink and not allowing the solder to flow). The problem was so severe that I even had a problem soldering the new caps.

What you mean to say is that the fan is on the bottom of the PSU rather than on the back.

Thanks, that is very helpful and is the conclusion I quickly came to when I opened up my case, saw the fan facing the interior, put my hand on the back of the power supply (outside the case) and felt the air coming out. It was then I realized that the airflow was identical to my existing PS.

Startech is absolute trash.

Message received (from you and elsewhere in this forum).

I decided to dive into the existing PS, and have removed the caps that appear to be part of the 5VSB circuit. They sure were easy to remove (twenty seconds apiece) which was a relief after the 1/2 hour per cap on the mobo. I've started to put the new ones in, and it is a little tough to snake them in around those heat sinks with the overhang.

I don't have my ESR setup handy (I use my own home-brew audio oscillator and resistor circuit which takes awhile to set up), but I did a capacitance and leakage test, and several of the caps measure below nominal, and two have leakage. I've got some slightly used Nichicon parts I'm going to install, and see what happens. The ones I've removed all are Teapo, which I gather from this forum are not good quality.

[mockingbird]

Re: Intermittent power on - P4PB-400 w/ FSP350-60BN PS

I am well aware of that, but it took me about four hours to replace the seven caps (it was seven on my mobo, not ten) because of the problem I mentioned earlier. I've never had that problem before (of having a ground plane act as a heat sink and not allowing the solder to flow). The problem was so severe that I even had a problem soldering the new caps.

I'm surprised, because this motherboard should be pre-RoHS and have leaded solder. Try desoldering plasma hybrid modules or caps from Xbox360 boards, then you will see truly difficult desoldering.

It takes a certain amount of practice, and if I were you I wouldn't try this the first time on a board I actually need, but in cases like this I don't clear the solder holes with wick. What I do is add a bit of fresh solder to the bottom pads and then rock the replacement cap in from the top while heating the bottom pads.

Also, you might have better luck using narrower diamter wick. I recommend 0.050" or less for mother capacitor lead holes... Make sure you've cut the used portion off before wicking away a new hole so that you're wicking it with the very end of the spool. The idea here is that there is no used wick ahead wicking away heat. Also, while you heat the wick, pull on the spool a little so that the wick is stretched and the braid tightens. This way, there is no air insulating the individual strands. I assume you are using high quality fluxed wick.

If you get frustrated while working on it, don't continue. I often find that when I work while I'm frustrated I tend to rip off pads.

I don't have my ESR setup handy (I use my own home-brew audio oscillator and resistor circuit which takes awhile to set up), but I did a capacitance and leakage test, and several of the caps measure below nominal, and two have leakage. I've got some slightly used Nichicon parts I'm going to install, and see what happens. The ones I've removed all are Teapo, which I gather from this forum are not good quality.

Can you check near the primary caps if your model has a 5vsb standby chip? Just curious, as I've never heard of this FSP model before. Keep us posted.

[Pentium4]

Re: Intermittent power on - P4PB-400 w/ FSP350-60BN PS

What series Nichicon caps are they? If they're HM don't use them in a PSU their ESR is too low. Pretty sure there is no 5VSB IC chip in that model

[johnmeyer]

Re: Intermittent power on - P4PB-400 w/ FSP350-60BN PS

What series Nichicon caps are they? If they're HM don't use them in a PSU their ESR is too low.

Yes, they are HM, but I used them on the motherboard.

I did a partial re-cap of the PS tonight, but the problem remains.

So, I've partially re-capped the motherboard, but don't want to proceed further because it is so difficult to remove and then replace the caps connected to the huge ground plane, and the ten year old PS probably isn't worth spending more time doing a complete, proper re-cap. For now, the computer continues to run fine, as long as I unplug it and wait for ten minutes before trying to start again. This is probably not going to last forever, however. Since I still would like to use this computer, I'll spend the $50 on a new PS and see if that fixes the problem. I'll take the advice given here as to what power supply to get.

Thanks to everyone for their help.

[johnmeyer]

Re: Intermittent power on - P4PB-400 w/ FSP350-60BN PS

I purchased a new power supply from Newegg. I'll post here next week as to whether this fixed the problem.

[johnmeyer]

Re: Intermittent power on - P4PB-400 w/ FSP350-60BN PS

Antec PS arrived an hour ago from Newegg. It is DOA. Bummer.

I'm giving up on this project. I can still use the computer as long as I unplug it between uses. I've killed way too many hours on this. I'll wait until it is totally dead, and then decide if I want to spend more hours trying to troubleshoot and fix it.

It won this round ... (so much for my 40-year-old EE degree).

[mockingbird]

Re: Intermittent power on - P4PB-400 w/ FSP350-60BN PS

The only Antec series I would touch are HCG, HCG-M, or HCP series.

The OEMs vary, the lower watt units being Seasonic OEM and the 700W+ units being Delta. They both have all Japanese electrolytics. I would stay away from the EarthWatts series. Although some of them are also Delta OEM (These being with the "D" suffix), and therefore built extremely well, the majority of the caps are LTec, and only a few UCC.

[Pentium4]

Re: Intermittent power on - P4PB-400 w/ FSP350-60BN PS

What model Antec was it?

[mockingbird]

Re: Intermittent power on - P4PB-400 w/ FSP350-60BN PS

Ah, I forgot to also add the Antec Truepower "New" (The ones with the green/black label) which are very nice and are a cross between Seasonic S12-II and the newer X platform. All Japanese caps, IIRC also the polymers are Japanese.

[johnmeyer]

Re: Intermittent power on - P4PB-400 w/ FSP350-60BN PS

What model Antec was it?

Antec EarthWatts Green EA-380D Green 380W Continuous power ATX12V v2.3 / EPS12V 80 PLUS BRONZE Certified Active PFC Power Supply

The issue with this supply has nothing to do with capacitors: it was simply DOA.

[mockingbird]

Re: Intermittent power on - P4PB-400 w/ FSP350-60BN PS

I would have spent another $5 and gone with the Rosewill RG430-S12, which is a nice little ATNG/Teapo unit.