power supply load - suggestions?

[kenzo42]

hi everyone,

my power supply unit needs some sort of load since it won't be using a PCB and because my monitor and its controls are jacked through it:

5v - 7A
12v - 1.5A
-5v - .1A

can anyone suggest some sort of load to place on this, at the wires coming from the jamma fingerboard, so i won't blow out the power supply? perhaps resistors would work? thanks.

kenzo

[ShinAce]

A 100 ohm resistor(1/2W or greater) on the -5 volt line will do.

I'd use light bulbs on the +5 and +12.
Something like a 5-10 watt 12 volt bulb, and a 15-20 watt 5 volt bulb.

[Ken Layton]

Actually some power supplies run fine with no load connected. The "Peter Chou" screw terminal series will work perfectly fine without a load as it has internal load resistors. Can you post a picture of it?

The "computer" style power supplies are a different story. Usually 99% of those must have a load connected. In those instances you must at the very least have a load on the +5 volt line and the +12 volt line that will draw at least 2 amps from the supply. Connect a 1 ohm 25 watt resistor to the +5 volt line and ground. Now get a 12 ohm 15 watt resistor and connect it from the +12 volt to ground. Forget about loading  the -5 volt line.

Those resistors will get hot in operation so ventilation around them is needed. Keep paper or meltable material away from them.

[kenzo42]

thanks for the replies.

1) are there specific GROUNDS that correspond to the 5v and 12v lines, when wiring in the resistors? could you point out the recommended grounds and 5v, 12v pin outs on this fingerboard. i ask because there are 2 sets of everything!



2) also, is there a special type of resistor i should use? like the square ones on monitors?

tia

[SirPeale]

Why don't you just pull the wires from the power supply?  Or put a switch inline on one of the power leads, if you want to swap out JAMMA boards.

Or are you doing something completely different?

[kenzo42]

the monitor and monitor controls are wired through the power supply. very strange indeed.

[Ken Layton]

The resistors are long rectangular ceramic types ranging from 2" long to 3" long and they get HOT.

Both of the resistors I mentioned will have one side of each resistor connected to that ground pad next to the 5 volts on that fingerboard.

[kenzo42]

ken, i posted some pics of the psu. can you tell me if there are internal load resistors on this psu? thanks.

http://pg.photos.yahoo.com/ph/liu_feng_yi/detail?.dir=/48ad&.dnm=e823.jpg&.src=ph

http://pg.photos.yahoo.com/ph/liu_feng_yi/detail?.dir=/48ad&.dnm=d22b.jpg&.src=ph

http://pg.photos.yahoo.com/ph/liu_feng_yi/detail?.dir=/48ad&.dnm=40a5.jpg&.src=ph