Friday, October 12, 2012

Bargain 12V 32A HP PS-3381-1C1 Power Supply pin out

At the last trash and treasure at Dural I was lucky enough to be steered to a bargain at $10 each. There was a pile of switching power supplies that are known for the low RF noise. HP PS-3381-1C1s.

When you power them up the +12V rail isn't active and a few jumpers are needed to get this going. I found the necessary wiring in a radio control group so I guess these supplies are also used for charging big batteries. Here's the three jumpers to earth I added to get it started:

And here's the 12V out at up to 32A (although I'm not sure my wiring would cope with that for long).

The fan isn't too bad, particularly given the high current capacity. Mine outputs 12.3V but I understand there are modifications for pushing that up to 13.8V to get the most out of some transmitters.


M6XKX said...

Thanks for the guide. I've just followed this to wire up one of my own. Reads 12.12v on my (rather cheap) multimeter.
I'll be testing it a little more thoroughly with some proper equipment before connecting it to anything expensive mind!
FYI there's a very extensive article on the use of these types of power supply in this month's RadCom.

Anonymous said...

I just bought one of these on ebay for also little money, and found this post completely by accident!
Thank you so much for caring to post this, it will save me a lot of time :).
Also, holy cow 32A at 12v? amazing!

phreedom karess said...

using these one must keep in mind the actual power being sucked from the 120vac lines. 12v x 32 amps = about 320 + 64 watts = almost 384, 'dead in the water' DC watts. assuming some conversion loss at even a good rate of 90 percent and the 120vac watt demand runs up over 400 watts. not a huge amount for those accustomed to multi "kill"-o-watt rigs, but nevertheless, should be aware of your shack's breaker box limits or use of extension cords (bargain types?)to reach remotely placed equipment platforms. when the lights dim when you key that rig, beware! safety first, performance last!