Mini-box PS-70 failure
Aaarrgh!!! My Mini-box PS-70 just crapped out after 4 hours of operation time (as best as I can tell). Here's what happened: it worked, I turned it off, I turned it back on 1 minute later, it didn't work anymore. Now all I see on the +5V rail is 0.8V. I still have +12V, +3.3V and -12V, it's only the +5V that doesn't work. This is with load and without loads attached to the power plugs.
I have always had a few problems with this power supply, i.e. sometimes it refused to turn on if I had just powered it down. Waiting 10 minutes would solve the problem. My motherboard is properly gounded, so I'm not sure exactly what causes this problem. Sometimes it turns on when I press the button, sometimes it turns on after I RELEASE the button. One time it wouldn't shut down no matter how long I held the button, necessitating a hard shutdown.
At the time of failure, I had very little on the rail: a 120GB Seagate Barracuda and a M10000 Nehemiah. The battery gives out 12.3V, so this cannot be the problem either.
I am prepared to solder a few components if this can help me get back on the road faster. Could this be a transistor that has suffered a polarity inversion? I know that in this case a fried transistor will pass exactly 0.8V. Hmmm...
I've emailed Mini-box.com two times and they won't email me back. Any idea what happened?
Talk to this guy - they make it, or oem it from someone, in any case, they know the circuit.
Andrei Bulucea email@example.com
One thing about I-tuner is it is pretty much a mom and pop operation. They are not a huge company, in fact to my knowledge there are probably only 5 actual people involved in the company operations. (They do have programmers and stuff elsewhere I believe.) At anyrate the point is, that Andrei guy is the brains of the operation. If you can get his attention, provided he's not swamped with stuff he will probably try to help you out.
The thing that I like about this Andrei dude is he has included ton's of documentation on using their power supplies in cars even though none of their own computers are meant for car applications. This tells me that this guy listens to what people wants and trys to satisfy the want.
Anyway, good luck on breathing life back into the power supply.
Since im re - reading thiis thread...
I blew my first pw-70 about an hour after hooking it up - for no apparent reason. It was exchanged verry quickly, and I quickly blew the fuse on the replacement unit.
All this with way less than the rated load on the supply. I would say 65 % load.
I didnt ask for a refund, but : ITS GOING TO BE A COLD DAY IN HELL before I risk hooking 1,000.00 worth of heardware up to this 50.00 wana be. Its just not worth the risk.
I wrote a VERRY DETAILED review of it on my site... lots of pictures and specs on the voltage cut offs. http://www.hjnetworks.com/car/pw120/
I'm sure you know what you are doing when you hooked up this supply but I've thrown quite a bit of abuse at my supply and it is working without any problems. Could be they had a bad batch come threw their manufacture or something, who knows. You are right in the fact that it is what it is, a 50 dollar DC-DC power supply.
Hopefully if this guy comes out with the 12v regulator then it will be even better. At the moment though it is only good for laptop devices that don't use 12volts.
Happy ending to the story-- Andrei sent me a replacement unit, and everything is good.