12 May
2006
12 May
'06
3:39 p.m.
From: Roger Merchberger <zmerch-cctalk at
30below.com>
The problem is I need to use a PC power supply (AT-class with it's own
power switch) as a 12V power source, and the only one I have access to
needs a minimum load of 3Amp on the +5Volt line.
How about a light bulb? I'd try a bulb for an automotive brake light. If
one's not enough, you could connect a few in parallel. If you find the
6V variety, it might work even better, but you should at least draw some
reasonable current with the 12V ones. If you really wanted to have
fun, you could try a headlight...
BLS
12 May
12 May
3:51 p.m.
The problem is
I need to use a PC power supply (AT-class with it's own
power switch) as a 12V power source, and the only one I have access to
needs a minimum load of 3Amp on the +5Volt line.
How about a light bulb? I'd try a bulb for an automotive brake light.
If one's not enough, you could connect a few in parallel. If you
find the 6V variety, it might work even better, but you should at
least draw some reasonable current with the 12V ones. If you really
wanted to have fun, you could try a headlight... 
4:08 p.m.
Dennis Boone wrote:
what happens when you hook up some extra IDE drives? I have never had
them fail to come
up with a couple of extra IDE drives hooked up. I don't recall what the
Dale resitors were in the
boxes IBM used to ship in the extra drive bay, but they were sufficient
on their own to
load the supply. It didn't take the motherboard on those original 130
watt IBM
supplies to start them, just the drive bay load resistor.
Jim
The problem is I need to use a PC power supply
(AT-class with it's own
power switch) as a 12V power source, and the only one I have access to
needs a minimum load of 3Amp on the +5Volt line.
13 May
13 May
3:05 a.m.
jim stephens wrote:
Dennis Boone wrote:
what happens when you hook up some extra IDE drives? I have never had
them fail to come
up with a couple of extra IDE drives hooked up. I don't recall what the
Dale resitors were in the
I've never seen a power supply that wouldn't start with an IDE drive
attached. Come to that, I haven't seen one that wouldn't start with
just the 12v line loaded, but I can believe it happens.
I can't see where you'd need to sink 15w to get it running - is the 3A
minimum from the spec sheet? Have you tried it with less?
Gordon.
> The
problem is I need to use a PC power supply (AT-class with it's
own > >
power switch) as a 12V power source, and the only one I have
access to > > needs a minimum load of 3Amp on the +5Volt line.
10:24 a.m.
Gordon JC Pearce wrote:
I've never seen a power supply that wouldn't
start with an IDE drive
attached.
That's actually the only thing I use cruddy IDE junk for ;-) (well, OK,
there's an IDE drive in this laptop - but not by choice)
Come to that, I haven't seen one that wouldn't
start with
just the 12v line loaded, but I can believe it happens.
Hmm, I've got one like that - it regulates the +12V at a shade over +9V unless
there's a load on the +5V rail.
I tend to use that supply along with a sacrificial anode arrangement for
corrosion protection on old metal - it looks interesting with a big bucket, PC
power supply, and an IDE disk dangling in mid air.
cheers
Jules
3:11 p.m.
Rumor has it that Gordon JC Pearce may have mentioned these words:
jim stephens wrote:
See Tom's previous response of MTBF. I'm not trying to *get* the PS started
- I'm trying to *keep* it running for a very long time. If the minimum load
on a switcher isn't provided, the regulation circuitry can start
oscillating, and eventually swing wider & wider off the target voltage,
with the possibility of eventually destroying the PS. Once the PS is dead,
the target equipment (assuming the PS didn't take it along to the happy
hunting grounds) will cease their functioning, resulting in (prolly quite a
few) unhappy customers[1].
Dennis Boone wrote:
what happens when you hook up some extra IDE drives? I have never had
them fail to come
up with a couple of extra IDE drives hooked up. I don't recall what the
Dale resitors were in the
I've never seen a power supply that wouldn't start with an IDE drive
attached. Come to that, I haven't seen one that wouldn't start with just
the 12v line loaded, but I can believe it happens. > The
problem is I need to use a PC power supply (AT-class with it's
own > >
power switch) as a 12V power source, and the only one I have
access to > > needs a minimum load of 3Amp on the +5Volt line.
> I can't see where you'd need to sink 15w to get
it running - is the 3A
minimum from the spec sheet?
Yup. Found the spec sheet for exactly that PS at Jameco's website.
Have you tried it with less?
Unforch, I don't have enough time for 'try' - I only have time for "do it
as right as possible under the time constraints." That's why I was trying
to overshoot the spec instead of 'getting away with' undershooting it.
Thankfully, RatShack had power resistors (and amazingly, *enough* of them)
that I can goad into working so the discussion is moot, yet still
interesting. ;-)
Believe you me, tho - I'll get some "good" power resistors on order from
Mouser next week, just in case I'm expected to perform the miracle again... ;-)
Anywho, thanks for all the insight - I've already got the first bank
soldered up & have to put the PS under load to see how things go...
Thanks again!
Roger "Merch" Merchberger
[1] Not to mention my (or one of my cow-orkers, who at that time would
rightly be pissed at me) needing to drive nearly 100 miles to replace said
PS and possibly other equipment to make the unhappy customers less
unhappy... That type of 'job performance' tends not to look good on
employee review day... ;-)
--
Roger "Merch" Merchberger | Anarchy doesn't scale well. -- Me
zmerch at 30below.com. |
SysAdmin, Iceberg Computers
14 May
14 May
4:27 p.m.
Roger Merchberger wrote:
[1] Not to mention my (or one of my cow-orkers, who at
that time would
rightly be pissed at me) needing to drive nearly 100 miles to replace
said PS and possibly other equipment to make the unhappy customers less
unhappy... That type of 'job performance' tends not to look good on
employee review day... ;-)
Why not use a more suitable PSU then?
Gordon.
12 May
12 May
4:09 p.m.
Rumor has it that Dennis Boone may have mentioned these words:
Or get thee to a shop and obtain three 5 watt 4.8 ohm resistors,
and wire them in parallel.
And can you get them at RatShack? That's the only "parts shop" I have
access to within driving distance (and by driving distance I mean 100 miles
in any direction whilst staying in the U.S. No, I haven't had a chance to
go get a $*#&#@^ passport just to go to Canada!!! :-/ ) - With their
current slogan of "You have questions, we have stupid looks & cellphones" I
doubt they carry anything of worth, let alone 5W power resistors...
However, I suppose I could go look...
Thanks!
Roger "Merch" Merchberger
--
Roger "Merch" Merchberger | "Bugs of a feather flock together."
sysadmin, Iceberg Computers | Russell Nelson
zmerch at 30below.com |
The problem is I need to use a PC power supply
(AT-class with it's own
power switch) as a 12V power source, and the only one I have access to
needs a minimum load of 3Amp on the +5Volt line.
How about a light bulb? I'd try a bulb for an automotive brake light.
If one's not enough, you could connect a few in parallel. If you
find the 6V variety, it might work even better, but you should at
least draw some reasonable current with the 12V ones. If you really
wanted to have fun, you could try a headlight...
6645
days inactive
6647
days old
7 comments
6 participants
participants (6)
-
blstuart＠bellsouth.net -
drb＠msu.edu -
gordonjcp＠gjcp.net -
julesrichardsonuk＠yahoo.co.uk -
jwstephens＠msm.umr.edu -
zmerch-cctalk＠30below.com