Power Supply

OK, I did a stupid thing, that is without question I was using a power supply tester and I was plugging in the floppy cable backwards (not intentional, just careless) and I got a blue spark and the PSU turned off. When I rehook everything the right way, all seems good. Was this just a protection mechanism that shut the PSU down and it is still good to go or did I permanently damage the thing?

Hi :). Not knowing the specs etc I will surmise a newer type of PSU. Some have a built in surge protector, since all appears to be working again I would not overly worry but keep a eye on things few a few hours. Make sure the actual PSU fan is active, no over excessive heat build up is present or smoke emitting etc. Fingers crossed :).

Yeah, I just bought the thing

http://www.sparklepower.com/pdf/FSP300-60PLN.pdf

Yeah, I just bought the thing

http://www.sparklepower.com/pdf/FSP300-60PLN.pdf

Should be ok it has the OVP / OCP / OTP / Short circuit protection :).

OK, I did a stupid thing, that is without question

I was using a power supply tester and I was plugging in the floppy cable backwards (not intentional, just careless)

The careless mistake was plugging the cable in backwards. It happens - The "stupid thing", however, was plugging in hardware while the PSU was plugged into the wall! Remember, anything that plugs into the wall can kill! But also, the ATX Form Factor standard calls for +5Vsb standby voltages to be present (normally across many points on the motherboard) when the PSU is plugged in to the wall - even if the computer is turned off. This +5Vsb is used for such commands as Wake on Keyboard, Wake on Mouse, Wake on LAN. It is also the voltage that signals the PSU to switch on when you push the front panel power button.

Because this voltage is always present (unless your PSU has a master switch on back, and it is turned off), you must always disconnect the PSU from the wall outlet before connecting or disconnecting any component from the motherboard, or the PSU power connectors - even when just testing with a tester (the exception would be for testing fans).

Some have a built in surge protector

No.

Short circuit protection

Yes!

@ajcstr - I suspect the spark you saw was the +12V jumping (arcing) to ground (or more negative potentials). I would not expect that to hurt the PSU, however, depending on where the +12V arced to, you may have damaged the floppy drive - which, fortunately are inexpensive.

That said, 300W is small for today's computers, especially with power hungry graphics cards. I recommend you use the eXtreme PSU Calculator Lite to determine your power supply unit (PSU) requirements. Plug in all the hardware you think you might have in 2 or 3 years (extra drives, bigger or 2nd video card, more RAM, etc.). Be sure to read and heed the notes at the bottom. I recommend you set Capacitor Aging to 30%, and if you participate in distributive computing projects (e.g. BOINC or Folding@Home), I recommend setting TDP to 100%. Research your video card and pay particular attention to the power supply requirements listed on your video card maker's website for your card. Then look for power supply brands listed under the "Good" column of PC Mechanic's PSU Reference List. Ensure the supplied amperage on the +12V rails of your chosen PSU meets the requirements of your video card. Don't try to save a few dollars by getting a cheap supply. Digital electronics, including CPUs, RAM, and today's advanced graphics cards, need clean, stable power. A good, well chosen supply will provide years of service and upgrade wiggle room. I strongly recommend you pick a supply with an efficiency rating equal to, or greater than 80%.

@ajcstr - I suspect the spark you saw was the +12V jumping (arcing) to ground (or more negative potentials). I would not expect that to hurt the PSU, however, depending on where the +12V arced to, you may have damaged the floppy drive - which, fortunately are inexpensive.

I was plugging the floppy connector on the PSU to a Power Supply tester, not an actual floppy drive, but I guess the other question is - did I fry the tester ? I was more concerned that the power supply actually shut itself off.

Also, this PSU is replacing a 250W PSU on an old machine. I ran through that tool you linked too and came up with a 167 w requirement

I was plugging the floppy connector on the PSU to a Power Supply tester, not an actual floppy drive

Ah, I see. But still the risk is there. Unless the device and connector are designed for "hot-swappable" connections, you should never connect or disconnect power cables to any device when there is power in one or both of the connectors. The chance a destructive voltage may come in contact with the wrong pin or socket is too great.

At any rate, it sounds like you are good to go, and thanks again for the follow up.

I was plugging the floppy connector on the PSU to a Power Supply tester, not an actual floppy drive

Ah, I see. But still the risk is there. Unless the device and connector are designed for "hot-swappable" connections, you should never connect or disconnect power cables to any device when there is power in one or both of the connectors. The chance a destructive voltage may come in contact with the wrong pin or socket is too great.

At any rate, it sounds like you are good to go, and thanks again for the follow up.

School of hard knocks is a tough one for sure - I may have gotten a "pass" here for a change but I will keep that in mind.

Thanks