ATX PSU stops after secs spinning

Retrofan · 01 March 2013, 11:41

Hi:
I've bought an ATX Psu, http://www.ebay.es/itm/251215530780?...ht_3962wt_1187 .

+3.3v with 30A
+5v with 40A
+12v with 22A
-12v with 0.8A
+5vsb 2A (no idea what's vsb)

500W.

First I've tried it with Ian's adapter and it was running right, but as I don't want so many cables around I've cut them. I've connected brown and orange together, just like the original 20pin connector had, and also green and black together for power on. There is also another grey cable, PG (Power good) that I've left unconnected.

Well, the Psu starts (I've got nothing connected), but stops (the fan) after a few spinnings.

Shouldn't it work even with no load, just like it was with Ian's adaptor? Or it won't stay on if I don't connect some resistor to the 5v or 3v line?

Loedown · 01 March 2013, 12:25

You've got nothing connected, you need to have something plugged in whether it's a floppy drive or a hard drive, doesn't need any controller into it just the power.

FOL · 01 March 2013, 12:26

Quote:

Originally Posted by Retrofan

Hi:
I've bought an ATX Psu, http://www.ebay.es/itm/251215530780?...ht_3962wt_1187 .

+3.3v with 30A
+5v with 40A
+12v with 22A
-12v with 0.8A
+5vsb 2A (no idea what's vsb)

500W.

First I've tried it with Ian's adapter and it was running right, but as I don't want so many cables around I've cut them. I've connected brown and orange together, just like the original 20pin connector had, and also green and black together for power on. There is also another grey cable, PG (Power good) that I've left unconnected.

Well, the Psu starts (I've got nothing connected), but stops (the fan) after a few spinnings.

Shouldn't it work even with no load, just like it was with Ian's adaptor? Or it won't stay on if I don't connect some resistor to the 5v or 3v line?

Maybe you have something connected to something it shouldnt.
Spinning for a second normally means its gone into protection mode due to a short.

You shouldnt need to connect anything to it. It should still run with no devices connected.

Retrofan · 01 March 2013, 13:28

Quote:

Originally Posted by FOL

Maybe you have something connected to something it shouldnt.
Spinning for a second normally means its gone into protection mode due to a short.

You shouldnt need to connect anything to it. It should still run with no devices connected.

Thanks. Can't be a short. I'm trying now with the Amiga psu cable disconnected, and all the cables disconnected.
No cables connected and the fan doesn't spin (normal);
Just green to black and it spins and stops.
Orange to brown and green to black and it's the same, spins and stops.

roy bates · 01 March 2013, 13:59

try it again with steadys adaptor,it could be a softstart supply.

also there should be a wire on the atx that permanantly outputs 5 volts for switching it on,you could check its actually outputting this with a meter.

Retrofan · 01 March 2013, 14:16

Quote:

Originally Posted by roy bates

try it again with steadys adaptor,it could be a softstart supply..

I can't use it again; all the cables are cutted.

Quote:

Originally Posted by roy bates

also there should be a wire on the atx that permanantly outputs 5 volts for switching it on,you could check its actually outputting this with a meter.

You are true. There is a purple cable with 5 volts even when the fan stops spinning and all the rest are showing 0v. What can I do?

Loedown · 01 March 2013, 14:24

Maybe you missed it the first time, put some sort of load onto it and it should start and stay on, you have already insisted that it isn't shorted and it may just be that without a load it isn't starting. Both FOL and I are not stupid and if you're really not sure why the hell are you risking your lovely expensive hardware with a half-arsed hack?

Retrofan · 01 March 2013, 14:33

Quote:

Originally Posted by Loedown

... why the hell are you risking your lovely expensive hardware with a half-arsed hack?

Perhaps I should remind you that it isn't connected to any amiga (yet), so I don't see that risk. Anyway, that's why I ask here.

So then it will need to run some resistors connected to 5v (red)?

Loedown · 01 March 2013, 14:41

Quote:

Originally Posted by Retrofan

Perhaps I should remind you that it isn't connected to any amiga (yet), so I don't see that risk.

So then it will need to run some resistors connected to 5v (red)?

http://brazenartifice.wordpress.com/...2v-regulation/

http://www.diyaudio.com/forums/every...-load-run.html

I should remind you that I get really tired of repeating myself and I get even more irritated by people who refuse to listen.

Retrofan · 01 March 2013, 15:34

Quote:

Originally Posted by Loedown

I should remind you that I get really tired of repeating myself

So you just have to answer no to my first question:

Quote:

Originally Posted by Retrofan

Shouldn't it work even with no load, just like it was with Ian's adaptor? Or it won't stay on if I don't connect some resistor to the 5v or 3v line?

I ask if I need in this PSU some load, you say to connect a floppy drive, FOL says:

Quote:

Originally Posted by FOL

You shouldnt need to connect anything to it. It should still run with no devices connected.

So exactly the contrary that you say, so I don't understand you either when you think you are saying the same that him
And you say:

Quote:

Originally Posted by Loedown

... and I get even more irritated by people who refuse to listen.

so who isn't listening?

And now to the point. This isn't my first ATX Psu. I've got 5, and all of them can run without any load on them, even the Amigakit PSU doesn't have a load for what I see.
Yes, I've put in them the load on 3.3v or 5v to stabilize the voltages, as Rkauer told time ago, just as LIKE your first link says "5v load ressistor for better 12v regulation". It doesn't say it's necessary for it to run. Only your second link says so.

And I would preffer an answer of FOL, roy bates or any other not so "tired", please.

DDNI · 01 March 2013, 16:08

Ooooh! A handbag fight

demolition · 01 March 2013, 16:14

I've seen a few PSUs that won't work without a load (e.g. the one I'm using for my Amigas) and some that does work, so unless someone has exactly the same PSU as you, we can't tell you for sure.

To turn on an ATX supply you need to short the green wire to a black (PS_ON to COM/GND).

k4lmp · 01 March 2013, 17:54

Quote:

Originally Posted by demolition

I've seen a few PSUs that won't work without a load (e.g. the one I'm using for my Amigas) and some that does work, so unless someone has exactly the same PSU as you, we can't tell you for sure.

To turn on an ATX supply you need to short the green wire to a black (PS_ON to COM/GND).

Yeah, what he said, this is a 'power on' from the motherboard, and the PSU won't work without the green going to ground.

FOL · 01 March 2013, 20:29

I have'nt come across any that dont work without load.
So I cant answer on this one, I just know that if something is short it will do exatly what you describe.

I would go with loedowns explaination, if your sure its not a short.
Have had the board out to remove wires or did you just cut them?
If you have lift it again and double check.

demolition · 01 March 2013, 21:02

Quote:

Originally Posted by FOL

I have'nt come across any that dont work without load.

I think it is a minority as well. I looked at my Amiga modified PC PSU (an old one that is) with an oscilloscope and it only gives small pulses at 1-2 Hz on the 5V output and most of the time 0V, so there's clearly some kind of 'sensing' going on that stops it from running without a load.

zharn · 01 March 2013, 22:39

Just by coincidence i retried my atx power supply last night. Ive tried three now and all did the same thing, works for 1 sec with amiga connected then powers down.

Turned out all i had to do was connect the amiga 5v to all the red 5v on the mobo connector and now the power supply will stay on. Used it for a couple of hours no problems.

Retrofan · 01 March 2013, 23:03

I wonder then how is that Ian's adapter can run all kind of atx psu's without any load, any big resistance on it. Perhaps killing that "sensing" pulse?.
And all the wires, Fol, were taked off just turning them around some times, as they are thin (not a good thing), but there's nothing left making a short.

Loedown · 02 March 2013, 00:06

Quote:

Originally Posted by zharn

Just by coincidence i retried my atx power supply last night. Ive tried three now and all did the same thing, works for 1 sec with amiga connected then powers down.

Turned out all i had to do was connect the amiga 5v to all the red 5v on the mobo connector and now the power supply will stay on. Used it for a couple of hours no problems.

Well would you look at that, someone applies some load to their PSU and it works.

Retrofan · 02 March 2013, 00:10

Thanks Loedown and excuse if I seem rude. That's the idea I had from the beginning, so I will try with some resistors when I can get them.

zharn · 02 March 2013, 00:26

Ive tried adding resistors on 5v when only needing 12v rails and made no difference, power supply still shutdown, i was pulling over 200w on 12v and 0w on 5v. To fix it i used another supply and changed way i was switching the 12v on and off to be a bit smoother.

Back to amiga...
I have to pull this supply apart, but i suspect there are multiple 5v rails and connecting all of them together is why its now working. Before i only had 2x 5v wires connected now i have 4.

I too looked at ian adaptor and schematics (looking for a load) and saw all the mobo connector 5v pins connected together.

01 March 2013, 11:41	#1
Retrofan Ruler of the Universe Join Date: Mar 2010 Location: Lanzarote/Spain Posts: 6,195	ATX PSU stops after secs spinning Hi: I've bought an ATX Psu, http://www.ebay.es/itm/251215530780?...ht_3962wt_1187 . +3.3v with 30A +5v with 40A +12v with 22A -12v with 0.8A +5vsb 2A (no idea what's vsb) 500W. First I've tried it with Ian's adapter and it was running right, but as I don't want so many cables around I've cut them. I've connected brown and orange together, just like the original 20pin connector had, and also green and black together for power on. There is also another grey cable, PG (Power good) that I've left unconnected. Well, the Psu starts (I've got nothing connected), but stops (the fan) after a few spinnings. Shouldn't it work even with no load, just like it was with Ian's adaptor? Or it won't stay on if I don't connect some resistor to the 5v or 3v line? Last edited by Retrofan; 01 March 2013 at 11:51.

01 March 2013, 23:03	#17
Retrofan Ruler of the Universe Join Date: Mar 2010 Location: Lanzarote/Spain Posts: 6,195	I wonder then how is that Ian's adapter can run all kind of atx psu's without any load, any big resistance on it. Perhaps killing that "sensing" pulse?. And all the wires, Fol, were taked off just turning them around some times, as they are thin (not a good thing), but there's nothing left making a short. Last edited by Retrofan; 01 March 2013 at 23:11.

02 March 2013, 00:10	#19
Retrofan Ruler of the Universe Join Date: Mar 2010 Location: Lanzarote/Spain Posts: 6,195	Thanks Loedown and excuse if I seem rude. That's the idea I had from the beginning, so I will try with some resistors when I can get them. Last edited by Retrofan; 02 March 2013 at 00:34.

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01 March 2013, 12:25	#2
Loedown Precious & fragile things Join Date: Feb 2009 Location: Victoria, Australia Posts: 1,946	You've got nothing connected, you need to have something plugged in whether it's a floppy drive or a hard drive, doesn't need any controller into it just the power.

01 March 2013, 13:59	#5
roy bates Registered User Join Date: Apr 2011 Location: birmingham Age: 55 Posts: 2,827	try it again with steadys adaptor,it could be a softstart supply. also there should be a wire on the atx that permanantly outputs 5 volts for switching it on,you could check its actually outputting this with a meter.

01 March 2013, 14:24	#7
Loedown Precious & fragile things Join Date: Feb 2009 Location: Victoria, Australia Posts: 1,946	Maybe you missed it the first time, put some sort of load onto it and it should start and stay on, you have already insisted that it isn't shorted and it may just be that without a load it isn't starting. Both FOL and I are not stupid and if you're really not sure why the hell are you risking your lovely expensive hardware with a half-arsed hack?

01 March 2013, 16:08	#11
DDNI Targ Explorer Join Date: Mar 2006 Location: Northern Ireland Posts: 5,433	Ooooh! A handbag fight

01 March 2013, 16:14	#12
demolition Unregistered User Join Date: Sep 2012 Location: Copenhagen / DK Age: 44 Posts: 4,190	I've seen a few PSUs that won't work without a load (e.g. the one I'm using for my Amigas) and some that does work, so unless someone has exactly the same PSU as you, we can't tell you for sure. To turn on an ATX supply you need to short the green wire to a black (PS_ON to COM/GND).

01 March 2013, 20:29	#14
FOL PSPUAE DEV Join Date: Nov 2006 Location: Wales / UK Age: 45 Posts: 6,040	I have'nt come across any that dont work without load. So I cant answer on this one, I just know that if something is short it will do exatly what you describe. I would go with loedowns explaination, if your sure its not a short. Have had the board out to remove wires or did you just cut them? If you have lift it again and double check.

01 March 2013, 22:39	#16
zharn Registered User Join Date: Nov 2012 Location: Brisbane Australia Posts: 150	Just by coincidence i retried my atx power supply last night. Ive tried three now and all did the same thing, works for 1 sec with amiga connected then powers down. Turned out all i had to do was connect the amiga 5v to all the red 5v on the mobo connector and now the power supply will stay on. Used it for a couple of hours no problems.

02 March 2013, 00:26	#20
zharn Registered User Join Date: Nov 2012 Location: Brisbane Australia Posts: 150	Ive tried adding resistors on 5v when only needing 12v rails and made no difference, power supply still shutdown, i was pulling over 200w on 12v and 0w on 5v. To fix it i used another supply and changed way i was switching the 12v on and off to be a bit smoother. Back to amiga... I have to pull this supply apart, but i suspect there are multiple 5v rails and connecting all of them together is why its now working. Before i only had 2x 5v wires connected now i have 4. I too looked at ian adaptor and schematics (looking for a load) and saw all the mobo connector 5v pins connected together.

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