Thread: ac switching power supply question.. Is this thing ready to explode?

Tweet

i have this old ac switching power supply to power my wiper motor.

its out of an old stand up arcade console.
i've wired it up and everything runs fine, however i'm getting an unusual hissing noise from the powersupply itself.

it sounds exactly like air leaking from a flat tire. theres no fans, i can't see any sparks/arch's/burning/damage etc but its a hiss'n

any idea's what would cause this? is a cap or something ready to explode?
any help would be greatly appreciated. i'd hate to burn down my home for halloween.


thx

Maybe it's haunted? Seriously though, I don't know if I'd use it, plus I think the wiper motor likes DC but then I can't really see what the output on your supply says where you have made your connections.

Does the P.S. make the noise...without the motor connected to it?

The hissing is usuaully a sign of a bad capacitor. ive had this happen on network switches, some died completely, some keep working for years. usually a good sign its time to replace the power supply. better safe then sorry.

ac input, dc output.

so, wires plugged into the outlet

white-ac
black-ac
green-fg

now the power supply hisses without the motor hooked up. but it also hisses with the motor hooked up.

other than the noise, everything else seems fine. no visible damage on the board, no burning/electrical odor, motor works (slow speed and fast) no sparatic behavior.

hooking up the motor to the power supply.

motor ground - gnd
jumper- +12v2a

i also tried the jumper on the +5v11a. (motor runs a little slower, still hisses)

doing a little research,i just read "hissing or white noise can be common with these powersupplies" ( under light load)

i don't believe everything i read on the net, so i'm looking for a second opinion.

what do ya think?

A little hissing is common in the arcade ps and I honestly don't think it will hurt anything to use it the way it is. If it goes out the motor will stop working and more than likely the PS has a fuse that will blow if it gets to over heated or shorts out. I had a few PS that I used that came with a train set and they hissed. One went out but two worked for a couple years and still worked but I scored a huge box of PC, PS, so I switched them.

If you open the case and see swollen electrolytic capacitors then that is the problem. They swell up and hiss. They are usually flat on top, the picture below will show you a bad capacitor.

thats what it is, one bad cap.

thx

gonna use a different one until i get the cap replaced.

yeah. i was going to say.. bad cap..
i have about 5 games in my basement and had to replace one of these that was hissing. cap replacement is pretty easy if you can find the right one.

i am also using a couple of these to power my props this year because i had them readily on hand.