this keyboard has a few missing keys. i'll follow up.

OK here we go.

PilotNut wants to power up a light bar. He located this supply and sent it to me.

The PC Power supplies have an orange wire we want to locate. To hot wire the power uspply to produce power we connect the orange to the red wire. This is the power good signal the PC motherboard normally send to the PS to get it to turn on all the way.

Red is +5VDC
Yellow is +12VDC

This supply has on it that the +12 VDC Circuit is 8 Amps. that's only 96 Watts of power. This will not produce enough power for the entire light system of PilotNut's. It would work the motor (( Internal Combustion Engine ? )) and a light possibly.

I found it shutsdown if I try and connect the Hobbs flood light.
But, I can power up two smaller round lamps.

This supply's voltage adjust is off. Its low by a quarter of a volt with no load. With these two lamps on it drops another volt. I opened it up to look for an adjust but no luck.

If we used a couple more of these and wired the light bar independently we could get it to run.

So do you recon the power pack is malfunctioning or is that particular pack simply not capable of kicking out enough juice?

I'll measure the current draw and check.
I think its working within its designed limits (even though its no load voltage is low)

It just can not produce enough power. I looked over the weekend for some old stuff I had and I suspect I through them away. But the shop is a total mess right now as we're building a bunk bed for the little tike.

Are you wanting to just use this light bar in the house using 110v. If so try using one maybe two battery and use the power supply if regulated to charge the batterys at 14 to 16 v the 14 to 16 v will drop under load to 12 to 13 If you use two batterys put them in paraell with each other to increase the run time. Figure you amp hour of your batterys to determin the the run time and charge time. A stand alone power supply will must likly fail with the surge of the light bar( rotating light and strobes). The power supply will need to be rated 50% larger than the load to work effencyly with out over loading the rectifier and triping out. If you choose not to run batterys get a 110v ac to 12 v ac step down transformer large enough to do the job, than use a rectafier to convert to dc. If you can find find a cheep 50 amp battery charge this will work for short periords or you can take it apart and build your own. The rectifier must be keep cool to prevent for tripping out. The heat lose( IR-2) is why you need to be 50% larger than the load when not using batterys.

I meant to mention that a trip raido shack might be the ticket. You can ask them what kva size you need. VA is aparent power and W is accual load in resistance. Size you KVA( kilo(1000) volt amp) trans by using a 80% power factor with 3% taps ( pf=w/va,w=va x pf). The reason for the taps is you figure the size (kva)using 125V and the house voltage maybe + or - 3% an will need to be taped accordingly to keep to out put voltaqge right. Your secondary conducters( 12v side) will need to be sized according to the load at 150% for continous duty. To small of wire it will get hot and burn up