PSU fan stopped...

[tom66]

I have a media PC, which sits next to the TV. It doesn't get a lot of use and it isn't a high spec machine, but can play 1080p and some games. Normally it is very quiet. When I woke it up from standby it booted fine but there was a very loud high pitched whining from the PC.

Upon inspection I found the PSU fan to have stopped. It twitches every 5 seconds or so. If I give it a spin with a pencil, it will turn for maybe 1 second and then stop.

The PSU is a cheapo 650W (Atrix 650/500T) unit I got from my brother who has to have the latest and greatest so I always get last year's technology for nearly nothing. I don't think it's high quality or truly capable of 650W, but I don't need the full 650W as this machine pulls less than 30W from the mains most of the time.

I'm not sure how long the fan has been stuck like this - maybe since the whining started, so only today, but perhaps longer. Maybe the whining is a symptom of a bad cap from the high temperature due to reduced airflow.

The computer still works fine, rails are good, and it's stable... what should I do? Can I replace or repair these fans?

For now, I'm not going to power up the PC.

[Evil Lurker]

Re: PSU fan stopped...

Replace the fan. Its a very simple task.

For the fans that are still working, take the sticker off the back and give them a good lubing with some light weight oil... a drop or two should do fine.

[mariushm]

Re: PSU fan stopped...

The fans inside power supplies are standard, just like the ones you put on the case for extra air.

In your power supply in particular, it's a 120mm fan. Select one that has just two wires, usually black and red...

Open up the power supply (remove the power cable first, make sure there's no power in it), unscrew the old fan, unplug it from the psu board, screw in the new fan, plug it in the board and you're done.

The page here shows you the white connector in the last picture :

http://www.overclockersclub.com/revi...rix_500t/2.htm

if you can't find fan with just 2 wires, the ones with 3 wires work just as well. But you'll need to cut the wires of the old fan somewhere in the middle, cut the connector of the new fan, connect the two black wires and the two red wires, use some duct tape to insulate everything including the third cable that's left hanging (that's for telling the speed of the fan to the pc - this psu doesn't use that wire)

[tom66]

Re: PSU fan stopped...

Okay, I'll buy a new fan. Just checked and it is 120mm. I will look for a quiet fan but the PSU has never been noisy and the fan usually runs very slowly when working so I'm not too worried.

While I have this PC open I think I'm going to work on making it quieter, which means the stock CPU fan will be tackled next and slowed down to run CPU at 60°C idle. (Runs at 30°C now, but at the expense of being loud.)

[lti]

Re: PSU fan stopped...

If this power supply has a fan controller, make sure it is working properly. Check the output voltage. If it isn't high enough to make the fan start, make sure the thermistor is still in contact with the heatsink or the component it was originally supposed to contact. I had a power supply where the fan didn't spin and another where the fan didn't spin quickly enough to cool it. In both cases, the thermistor was not in contact with the heatsink.

[tom66]

Re: PSU fan stopped...

So, I tore the PSU apart.

First thing I noticed is it has several bad caps, so I will replace them. They are CapXon. This PSU is on 24/7 in standby (<5W USB draw for battery charger and wireless mouse/keyboard) most of the time (probably 30% usage e.g. playing a movie) but has only been used for 6 months. CRAP!

Second thing I noticed was around the fan connector there was some burned plastic. This was probably produced by the nearby 2N2222A transistor which is right against this. I suspect this transistor has failed, to the point it's not providing sufficient current to the fan. I tested the fan on 12V and it works fine. I feel replacing the transistor won't be sufficient, as it might just die in 6 months anyway. I think I have a heatsink for a TO92 somewhere.

Also, the input cap - a 270u 450V - is way too small for a 650W power supply. If it's 650W, it's going to be pulling ~2.8 amps from the plug (at 230V), plus maybe 20% losses, so 3.4 amps. That would be about 125V ripple across that main cap. No way the switching side is going to cope with that.

What type of caps should I use to replace these? I'll be needing small diameter but tall capacitors. Rubycon ZLH? Panasonic FC?

[retiredcaps]

Re: PSU fan stopped...

What type of caps should I use to replace these?

What series are the Capxon caps?

[klkmalik]

Re: PSU fan stopped...

Replace the fan. Its a very simple task.

For the fans that are still working, take the sticker off the back and give them a good lubing with some light weight oil... a drop or two should do fine.

Also u can use WD40 oil spray just two drops in side sticker.

[Rulycat]

Re: PSU fan stopped...

NEVER use WD40. It is a terrible lubricant.

[Evil Lurker]

Re: PSU fan stopped...

NEVER use WD40. It is a terrible lubricant.

Agreed. But it can be used for cleaning out any old lubricant before putting in new lubricant.

[tom66]

Re: PSU fan stopped...

Original CapXon are LZ. But I doubt they'd match their spec, anyway...

The fan is fine, no need to replace it. I've found my TO-92 heatsinks but they look too big for the PSU with the nearby components. I might just bodge in a TO-220.

[Th3_uN1Qu3]

Re: PSU fan stopped...

Also, the input cap

If it has active PFC it'll be working at 400 volts or thereabouts, so the situation in the primary won't be that bad. That cap will have to swallow quite a bit of ripple tho, and given that it's 85C... yeah you should use something better there.

[tom66]

Re: PSU fan stopped...

If it has active PFC it'll be working at 400 volts or thereabouts, so the situation in the primary won't be that bad. That cap will have to swallow quite a bit of ripple tho, and given that it's 85C... yeah you should use something better there.

Yeah, but the ripple voltage equations mostly apply for PFC too (for COT topologies mostly.)

I've got a 470u 400V CapXon I pulled from an 850W version of this PSU. (which was a joke too) I might change it over.

I recently got an ESR meter but it's reserved for birthday in 5 days so can't test the caps yet, but it looks like 5 are definitely bad, and one is suspect.

[retiredcaps]

Re: PSU fan stopped...

Original CapXon are LZ. But I doubt they'd match their spec, anyway...

http://www.datasheetarchive.com/CapX...datasheet.html

Panasonic FM seems like a good match if I use the following example

Capxon LZ, 2200uF 6.3V, 10x16mm, 1910ma, 18mOhm
FM 2200uF 6.3V, 10x25mm, 2470ma, 18mOhm

http://search.digikey.com/scripts/Dk...2200uf+6.3v+fm

[tom66]

Re: PSU fan stopped...

http://www.datasheetarchive.com/CapX...datasheet.html

Panasonic FM seems like a good match if I use the following example

Capxon LZ, 2200uF 6.3V, 10x16mm, 1910ma, 18mOhm
FM 2200uF 6.3V, 10x25mm, 2470ma, 18mOhm

http://search.digikey.com/scripts/Dk...2200uf+6.3v+fm

I highly doubt the LZ's meet the spec as described in the datasheet. I'll take the shotgun approach: replace with very low ESR replacements (Panasonic FC, FM and FR are good, as are Rubycon ZL*.) I don't usually bother to match ESR, but maybe I should?

[retiredcaps]

Re: PSU fan stopped...

I don't usually bother to match ESR, but maybe I should?

PCBONEZ talks it about it here (I'm sure he can add more)

https://www.badcaps.net/forum/showpo...30&postcount=7

https://www.badcaps.net/forum/showpo...51&postcount=7

As for Capxon LZ meeting their spec, I have no clue.

[tom66]

Re: PSU fan stopped...

Rubycon ZLH's: http://uk.farnell.com/rubycon/16zlh1...16v/dp/8126291

1000u, 16V, 8x20mm, 1500mA, 29mOhm.

Compare to Capxon LZ (so claimed):

1000u, 16V, 8x20mm, 1850mA, 20mOhm.

Nichicon HM is better though: http://uk.farnell.com/nichicon/uhm1c...16v/dp/1823808 (and considerably cheaper.)

1000u, 16V, 8x20mm, 1870mA, 18mOhm

Either will be better than the LZ cap, I'll probably use the Nichicons.

[c_hegge]

Re: PSU fan stopped...

Go with the nichicon HM, since they are the closest to the specs of the originals.

[tom66]

Re: PSU fan stopped...

After replacing the caps (7 x 1000u and 2 x 680u) the power supply voltages are now all about 0.1V lower, which seems better. Also, replaced the transistor and the fan now spins. Happy days...

Used Rubycon ZLJ and Panasonic FM. Couldn't get hold of Nichicon HM as they were too expensive (cheap individually, but a ~£16 shipping charge!) I ordered the incorrect 10x16mm size, but I was still able to fit them in. I expect the Rubycons will be fine; the system isn't under much load and I'm very sceptical about the Capxons meeting their original claim of 18mOhm.

Next task - slowing down CPU fan...

[tom66]

Re: PSU fan stopped...

In fact I just tested some of the ones I removed:

- Capxon LZ 1000uF/16V on the LC filter output of 5VSB (so under very little ripple): 0.02 ohm, 1266uF. So it's quite a bit out of tolerance (26.6%, rated 20%) but I'm not sure if that would be much of a problem.
- Capxon LZ 1000uF/16V hideously bulged: 876uF 0.05ohm, ESR high, low capacitance but still within tolerance (barely.)
- Capxon LZ 1000uF/16V hideously bulged: 1050uF 0.05ohm good capacitance, but ESR too high.
- Capxon LZ 1000uF/16V hideously bulged: In-Circuit/Leaky 0.06ohm (multimeter cap range shows this as 834uF... must be too leaky for my Atlas ESR70.)
- Capxon LZ 1000uF/16V hideously bulged with black ooze: 1312uF 0.04ohm - another significant increase in capacitance
- Capxon LZ 680uF/16V slightly bulged: 1360uF(!!) 0.04ohm - More than double capacitance, what gives? ESR quite high too. Actually, I just realised I never checked this one and replaced it with 1000uF (because it was the same size as all of the other 1000uF). I don't think it will cause problems, but I have no idea which place it came from...
- Capxon LZ 680uF/16V slightly bulged: 1235uF(!!) 0.05ohm - Also a significant increase in capacitance & ESR... and also replaced with a 1000uF.
- Jun Fu WG(?) 680uF/16V not bulged: 732uF 0.06ohm
- Jun Fu WG(?) 680uF/16V not bulged: 732uF 0.03ohm note ESR half of the other one

Used an Atlas ESR70.

Anyone got the specs for the Jun Fu caps?