Dell 5161-7DS power supply - how to turn on using paper clip?

[retiredcaps]

A friend handed me 4 Dell GX280 all with bloated Rubycon caps near the CPU. I haven't opened up the power supplies, but they are 5161-7DS (20 pin).

According to diagram DC Power Connector P1 (about halfway down the page)

http://support.dell.com/support/edoc...g/pwrsply0.htm

pin 14 is PS_ON and pin 9 is 5V FP.

Normally, for an ATX power supply, I use a paper clip and short PS_ON to GND and the power supply turns on. From the diagram, this looks like an ATX power supply and all the pins correspond to an ATX power supply.

I can't do this for the 5161-7DS for some reason. I took a working 5161-7DS and tried shorting PS_ON to GND and got nothing. I tried adding a load (SATA hard drive) and still nothing.

Q1) What am I missing?

Q2) What does "FP" stand for in the 5V FP documentation?

[selldoor]

Re: Dell 5161-7DS power supply - how to turn on using paper clip?

Q1 - Pass

Q2 FLEA POWER ------- no I didnt think youd believe me!





http://answers.google.com/answers/th...id/185999.html

[selldoor]

Re: Dell 5161-7DS power supply - how to turn on using paper clip?

Well I have given it time for for someone to be brave enough to suggest this but in the absence of any takers.

Have you got the power switched on
Is the correct lead plugged in
Is the fuse in the plug OK
Have you tested the lead in something else.
Have you tried a different lead.

[retiredcaps]

Re: Dell 5161-7DS power supply - how to turn on using paper clip?

Q2 FLEA POWER ------- no I didnt think youd believe me!

http://answers.google.com/answers/th...id/185999.html

Hmm, another Dell unconvention.

And yes, I would not have believed you without the references. Thanks.

[momaka]

Re: Dell 5161-7DS power supply - how to turn on using paper clip?

Perhaps these PSU are more like LCD monitor PSUs? (i.e. you pull the PS-ON high to turn on the PSU).
Try pulling PS-ON up from 5V FP through a 100 Ohm resistor.

[retiredcaps]

Re: Dell 5161-7DS power supply - how to turn on using paper clip?

Well I have given it time for for someone to be brave enough to suggest this but in the absence of any takers.

Have you got the power switched on
Is the correct lead plugged in
Is the fuse in the plug OK
Have you tested the lead in something else.
Have you tried a different lead.

Sorry, somehow missed your post. I was probably distracted by the flea power post?? Suggestions are always welcome. I sometimes overlook the obvious.

1) There is no power switch at the back.
2) Not sure what you mean by lead, but I have done this many many times and I know I have the correct color (green for PS_ON).
3) The power supply work if it is connected to the motherboard and all output voltages are correct so the fuse is working fine.

There must be something else with these power supplies and causes them to turn on.

[retiredcaps]

Re: Dell 5161-7DS power supply - how to turn on using paper clip?

Perhaps these PSU are more like LCD monitor PSUs? (i.e. you pull the PS-ON high to turn on the PSU).
Try pulling PS-ON up from 5V FP through a 100 Ohm resistor.

When plugged into the AC outlet the 5V FP and PS_ON (on all 4 of them) measures 5.00V.

PS_ON is pulled low to 0.00V when jumpered with ground.

I don't have any resistors at the moment so I will have to break out the soldering iron and get one from a junk power supply.

I tried jumping all 4 and none of them startup. However, if they are connected to the motherboard, they all start. Looks like I will have to probe all the pins and use min/max to figure out what is going on.

[selldoor]

Re: Dell 5161-7DS power supply - how to turn on using paper clip?

Could it be something to do with Power OK signals Grey cable pin8
See https://www.badcaps.net/forum/showth...?t=4793&page=2
post 36 - Not sure why that came into thet thread but it might help.
If Pcbonez hadnt vanished he may have been able to advise.

[PeteS in CA]

Re: Dell 5161-7DS power supply - how to turn on using paper clip?

If the P/S has a UC384X type PWM controller, there's often a high value resistor and electrolytic cap (probably with a zener across it) that provide start-up bias. have you checked to see if the resistor is open, the zener shorted or the cap has worn out (high ESR)? That cap is one of the "little caps you should replace but might forget."

[retiredcaps]

Re: Dell 5161-7DS power supply - how to turn on using paper clip?

Could it be something to do with Power OK signals Grey cable pin8

Selldoor earns a well deserved this time around. His link to PCBONEZ's PWR_OK thread led me in the right direction.

For some reason, PWR_OK wasn't getting pulled up to 5V on this model. So I jumped 5V FP to PWR_OK in addition to PS_ON to GND. So with both jumpers in place, the 5161-7DS turns on. 3 out of the 4 power up, and of course the one that doesn't work is in the case with non bloated Panasonic caps by the CPU.

Now onto taking the covers off and seeing how dirty and how many number of bloated caps.

On all other ATX power supplies that I have at home including name and cheap brands require only jumping the PS_ON to GND.

PS. The reason I use the paper clip method for standalone power up is because when I get computers for repair, I don't want to fry the motherboard in case the power supply's 5V standby rail has failed high. One of my friend's Antec measured 11V DC on the standby rail and fried his motherboard.

PPS. Note to selldoor, time to change slow learner to Badcaps Veteran.