M2-ATX(-HV) 160 watt Intelligent DC-DC PSU - Page 6

rickd · 07-07-2009, 04:29 PM

Quote: Originally Posted by joshuo

The engine def. puts out tons of RFI, that's another reason why firewalls in cars are metal.
Just think of the amount of metal that spins at 1000's of RPMs and all the metal on metal rubbing... Add a turbo and it gets even worse.

another thought on shielding:
It could be as simple as covering the computer box with some sheet aluminum or even metallic paint?

Metallic paint? No. The case needs to have very low impendance. Think sheet metal, not a molecule-thick coating of metal on a piece of plastic, and definitely not metal particles that are effectively insulated from each other by the paint binder.

It isn't the spinning metal that makes the RFI, unless the metal is somehow magnetized (which you hope is not the case). It's the ignition system. Diesel engines are RF quiet--they have no ignition systems or spark plugs. That 20,000-volt spark plug, running through an inductive spiral-wound plug wire, makes a pretty effect spark-gap transmitter.

The alternator uses solid-state components to regulate voltage, and the switching of those components can also spray RFI.

Rick "thinking the shield on the radio antenna coax is the place to start" Denney

Sonicxtacy02 · 07-07-2009, 04:33 PM

i always heard it was bad practice to ground directly to the battery. Would a high gauge (4-8Ga.) wire run directly to the battery then split via distribution block to all computer components be advised. Right now my radios ground is not my computers ground because the ground would then have to travel the distance of the car. I've heard that ground wires need to be short even in high gauge

joshuo · 07-07-2009, 05:16 PM

^ get 10 ft of 10 or 8 gauge wire at a hardware store, and test it. just hold it to your PC ground and then to the neg battery terminal....

Doesn't hurt to try...

fatejd · 07-08-2009, 02:54 PM

I just upgraded my car pc and now I can't get power from my M2-ATX, at least I think that's the problem. I turn on the ignition and get the green standby light on my mobo and the dim HDD activity light on my case (my power light is not hooked up). Nothing else starts up: HDD, fans, monitor, etc. Could this be the polarity problem on the J8/J9 jumpers? Also, I looked through this thread and didn't see which pin is live and which is ground on these jumpers - did anyone figure it out?

Thanks

Sonicxtacy02 · 07-08-2009, 03:21 PM

Quote: Originally Posted by joshuo

^ get 10 ft of 10 or 8 gauge wire at a hardware store, and test it. just hold it to your PC ground and then to the neg battery terminal....

Doesn't hurt to try...

Just bought 20 feet of 8awg silver wire at parts express for 0.59/ft. Thanks for the suggestion

I just hope it works when it arrives.

Quote: Originally Posted by fatejd

I just upgraded my car pc and now I can't get power from my M2-ATX, at least I think that's the problem. I turn on the ignition and get the green standby light on my mobo and the dim HDD activity light on my case (my power light is not hooked up). Nothing else starts up: HDD, fans, monitor, etc. Could this be the polarity problem on the J8/J9 jumpers? Also, I looked through this thread and didn't see which pin is live and which is ground on these jumpers - did anyone figure it out?

Thanks

just take the jumper off of the motherboard and short the pins together to see if the fans spin and it boots. That will tell you if its the jumper or something else.

fatejd · 07-08-2009, 03:27 PM

Quote: Originally Posted by Sonicxtacy02

just take the jumper off of the motherboard and short the pins together to see if the fans spin and it boots. That will tell you if its the jumper or something else.

I tried taking the cable off the motherboard power switch pins and shorting them with a screwdriver and another piece of metal and nothing happened. I also have a molex > 4pin 12v connector going to the motherboard. I think I should get the 4pin > 4pin cable they have available at the store here and go directly from the PSU to the mobo, but I'm not sure if that's the problem. I just really think it's the M2 because if I turn it on it doesn't turn on my monitor, which is just spliced into a molex connector -and it worked previously that way.

joshuo · 07-08-2009, 04:28 PM

^ the monitor won't turn on until the MB commands the PS to turn on the accessories...It does this by shorting the green wire to one of the grounds. Try that, it should turn on all the rails...

fatejd · 07-08-2009, 06:08 PM

Do you mean the green wire in the ATX power connector harness? I don't think I want to cut that out and short it for this.

joshuo · 07-08-2009, 06:14 PM

Yes i mean that.
You don't have to cut it out, just short it with an unfolded paperclip when it's unplugged from the computer!

fatejd · 07-08-2009, 06:17 PM

Oh, so unplug it from from mobo and short it to one of the black wires?

joshuo · 07-08-2009, 06:20 PM

Yup! Can't hold me responsible for jumping the wrong ones though.

Just google how to test a power supply to be absolutely sure. It's been a while but i'm almost positive it's the green one.

fatejd · 07-08-2009, 06:44 PM

Ok, so it turns out it is not the power supply, must be the mobo or something on it...thanks joshuo!

Sonicxtacy02 · 07-11-2009, 10:52 AM

well i hooked the ground up to the battery and it actually made it worse somehow. it HAS to be EMI... if i power down my computer and run the hdradio to my receiver its crystal clear even thought its using the same antenna

joshuo · 07-11-2009, 11:05 AM

Well the last thing i can think of is to move the radio further away from the computer...

Sonicxtacy02 · 07-11-2009, 01:36 PM

Quote: Originally Posted by joshuo

Well the last thing i can think of is to move the radio further away from the computer...

did that when i first got the radio.. its in the dash and my computers in the trunk. that DID improve the signal some. Perhaps its time for me to just drop dime and purchase another PSU to compare.

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