Bad PSU ?

  • Thread starter Thread starter Graeme
  • Start date Start date
I've just tested a nearly identical machine (same PSU and mobo), and its 12V
rail also exhibits these drops.
The only other performance machine I have access to is our dual Xeon unit
which is hardly ever used. I've just probed its 12V supply and it is rock
solid stable. I had to remove the PSU to find out who the manufacturer is -
and - it's a 460W Fortron unit. Me thinks (from what I've heard on the
group) I'll get one of these.
Click to expand...

I have a 460W Fortron, it is a very nice unit... a good example of how
many parts they can stuff into one, it would be hard to build better into
a PS2 sized casing without doing away with the active PFC circuit. It's
also very quiet due to a well calibrated, high quality fan, used in
conjunction with pair of huge 'sink plates, one of which is sunk to the
outer casing.

However, it has twin 12V outputs, this "could" partially be why you didn't
see any fluctuation, if testing one while the other was used for CPU(s).

It is NOT a standard power supply, is for workstations, has a motherboard
24 pin and 8 pin connectors, not the standard 20 pin ATX connector nor the
ATX12V 4 pin connector. If you're interested in a Forton unit you might
consider their standard 400W model instead, available many places
including here:
http://www.newegg.com/app/ViewProductDesc.asp?description=17-104-974

They also have a new 400W model utilizing a 12cm fan, should be very quiet
as are their 300W and 350W models with similar design. It is too new for
me to recommend (read- I haven't gotten my hands on one to test or tear
apart yet), but considering their other units are good this should be no
exception:
http://www.newegg.com/app/ViewProductDesc.asp?description=17-104-962
However, except for the fan allowing for lower noise, I expect the first
linked unit to be better than the second, as that 12cm fan results in less
efficient use of the interior, likely a design optimized for lower part
count, though again I haven't examined that new model yet to be sure of
it.
 
kony said:
I have a 460W Fortron, it is a very nice unit... a good example of how
many parts they can stuff into one, it would be hard to build better into
a PS2 sized casing without doing away with the active PFC circuit. It's
also very quiet due to a well calibrated, high quality fan, used in
conjunction with pair of huge 'sink plates, one of which is sunk to the
outer casing.

However, it has twin 12V outputs, this "could" partially be why you didn't
see any fluctuation, if testing one while the other was used for CPU(s).

It is NOT a standard power supply, is for workstations, has a motherboard
24 pin and 8 pin connectors, not the standard 20 pin ATX connector nor the
ATX12V 4 pin connector. If you're interested in a Forton unit you might
consider their standard 400W model instead, available many places
including here:
http://www.newegg.com/app/ViewProductDesc.asp?description=17-104-974

They also have a new 400W model utilizing a 12cm fan, should be very quiet
as are their 300W and 350W models with similar design. It is too new for
me to recommend (read- I haven't gotten my hands on one to test or tear
apart yet), but considering their other units are good this should be no
exception:
http://www.newegg.com/app/ViewProductDesc.asp?description=17-104-962
However, except for the fan allowing for lower noise, I expect the first
linked unit to be better than the second, as that 12cm fan results in less
efficient use of the interior, likely a design optimized for lower part
count, though again I haven't examined that new model yet to be sure of
it.
Click to expand...

My Fortron unit also has twin 12V power outputs, and you're right, the
fluctuation is only present on the CPU connection (not the HD wire that I
was probing before) - even on the Fortron unit. However, the Fortron has
much smaller fluctuations (about 4ms in duration, and only about a 40mV dip)
than the Winpower unit.
So my choices are;
1) Get quieter fans so I can't hear the fan noise change,
2) Get a PSU with twin 12V outputs (and try to re-wire the connectors),
3) Run all fans from a separate 12V supply. [I just so happen to have a
DC-DC convertor component (2"x1") that will take 12V in and give 12V out.
The output won't fluctuate with a change in input, unless it goes below 9V].
4) Get on with the more important things in life! :-)
Thanks for your comments.
 
[snippity snip]
3) Run all fans from a separate 12V supply. [I just so happen to have a
DC-DC convertor component (2"x1") that will take 12V in and give 12V out.
The output won't fluctuate with a change in input, unless it goes below
Click to expand...
9V].

I'm happy now. I used one of our old DC-DC convertors (one of my old
designs) and stuck it on a bit of strip-board, with three 3-pin fan
connectors. Plugged it inline with the 12V power to my CD-RW and all fans
now run at a constant 12V (10mV ripple). I was a little concerned that the
PSU fan would fluctuate with different CPU loads, but it doesn't appear to
(of course it might not be connected to the 12V output).
I still think my Winpower PSU is crap though!
 
[snippity snip]
3) Run all fans from a separate 12V supply. [I just so happen to have a
DC-DC convertor component (2"x1") that will take 12V in and give 12V out.
The output won't fluctuate with a change in input, unless it goes below
Click to expand...
9V].

I'm happy now. I used one of our old DC-DC convertors (one of my old
designs) and stuck it on a bit of strip-board, with three 3-pin fan
connectors. Plugged it inline with the 12V power to my CD-RW and all fans
now run at a constant 12V (10mV ripple). I was a little concerned that the
PSU fan would fluctuate with different CPU loads, but it doesn't appear to
(of course it might not be connected to the 12V output).
I still think my Winpower PSU is crap though!
Click to expand...

Glad to hear you resolved this.

If you hadn't had the DC-DC convertor I might've suggested trying an LDO
regulator, running the fans at optimal noise level, whatever that might be
from ~6-10V, depending on the particular fan or just making it adjustable.

Even so, it would be good to replace the Winpower PSU... better now while
it still works, then you have a spare for emergencies.
 
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