Power missing to AMP

**Pint** · 10-01-2007, 08:05 AM

Hello.
I'm having a couple of power problems with my recently installed setup.
Here's my set-up -

Voom PC
Alpine PDX 4.1 amp
M2 ATX power supply
Affter I connected it all up yestoday there was no power to the AMP.
The PC booted up, but today it won't.

I've checked the supply to the PC and I get 12v from the live wire and 12v from the ignitiion wire.

I've also checked the AMP. I've got a current to the AMP. And when I check the RMT to the AMP from the PC. A couple of different things have happended. Once the AMP powered up for a split second(the lights flashed). On other attempts when I touch the RMT wire at the AMP with the volt meter, the PC powers up. When I touch the RMT wire again, the PC powers off.????

I can't see an on off switch on the amp - is there supposed to be one?

Thanks for your help....

**DarquePervert** · 10-01-2007, 08:48 AM

The live wire should get 12v all the time.
The ACC should get 0v when the key is off ans 12v when the key is on.

Have you measured the voltage on these lines with key on and key off?

Also, have you checked all your fuses? most amps don't have an on/off switch, just a remote wire that senses ignition state, much the same as your M2ATX PSU.

**RedGTiVR6** · 10-01-2007, 09:26 AM

There has never been an on/off switch on a car audio amplifier that I have ever seen, so that's normal.

However, I must ask how you have your amplifier wired up. Are you powering it off of the M2 or are you powering it off of the car battery?

From your post it seems like you might have it powered off of the M2. I say this because of how you have worded and lumped things together.

Have you checked to make sure you've not put the turn-on lead on the wrong pin on the M2?

**Pint** · 10-01-2007, 05:28 PM

DarquePervert - I'm prettty sure the 12v has live all the time and acc is via the key on and off. I'll double check.

RedGTiVR6 - I'm running the AMP off the battery, through a 80amp wafer fuse.

I'm pretty sure I have wired the pins properly on the M2, but I will double check. (I had to get a replacement internal power cable when the original broke and that could be a possibility)

I have the AMP earthed to the body. I pretty sure that it's a good connection, but I didn't sand the surface becuase it looked like bare metal. Will a less than 100% connection cuase my problems?

I'll check the wiring tonight and if it does'nt work, take the PC out and try it out of the car.

Thanks for your help.

**salvi** · 10-01-2007, 06:50 PM

On other attempts when I touch the RMT wire at the AMP with the volt meter, the PC powers up. When I touch the RMT wire again, the PC powers off.????

Are you sure that you didn't connect the Ignition wire to your amps instead of the remote wire? If not, check the inside wiring of the plug on the VoomPC and make sure that all wires line up to their corresponding wires outside of the case. I know that there was a case where the wiring was wrong from the inside and outside.

**DodgeCummins** · 10-01-2007, 10:17 PM

A speaker wiring problem could be causing the amp to remain off also...but check the obvious.

**Pint** · 10-02-2007, 08:40 AM

okay...
The AMP
There was a loose speaker wire (although I don't think that was my problem). I bypassed the PC and connected the RMT wire directly to a live feed which turned on the AMP. My AMP is good

The PC
Still no power to the PC
I took the PC out and had a closer look.
1. the iginition wire at the molex femal connector was very loose and wasn't connecting to the male. I fixed that. That's why my problem was intermittent and worked for a day.

Still no power to the PC
2. I screwed up when I replaced the power cable.

I had put the AMP RMT into the external on/off switch connector(J9 and not J6). That's why when I touched the wire at the amp the PC was starting up. Fxed that.

Still no power to the PC
I've verified that I have a 12V live to J1 (battery +), and J3 (ignition). I know I have power as the LED on the mother board lights up when it's connected.
The only other thing I've noticed is that it seems that the PSU is not sending a on signal to the motherboard. When I pull the connector off J8 (to the mother board on off switch) the PC starts up until I put the connector back on.
I have the jumper settings set to B 5sec offdelay/2hour hardoff

Not sure what to do next.

how can I tell whether the PSU is fried and I need another one?

**NorfwocNe** · 10-02-2007, 08:30 PM

Excellent troubleshooting. I'm impressed. Good luck.

**Pint** · 10-03-2007, 08:20 AM

Okay, I'm over it.

Still getting the mobo to start as soon as i unplug the J8 connector. As soon as I plug it in after a few seconds the mobo switches off.

From what I've read, changing the polarity of the J8 connectors might have helped. It didn't .

Back in 2005 there was a thread about the M2 not fully powering all the line and a timing issue which need a PIC fix...... sounds hard if you know nothing about programming like me.

two questions
1. The M2 is 160 watts, will the OPUS 120watt DCx3.120 be suitable for my Voom PC 2 / Jetway mini ITX motherboard?
2. Is PIC programming hard.... can someone recommed somewhere to start?

help is very much appreciated.

**Uraijit** · 10-03-2007, 08:30 AM

So when you disconnect the power jumper cable, the computer boots up? What happens when you reconnect it? Does it just lose power alltogether, or does it initiate shut-down?

I can't help you with programming, but to answer your PSU question, a 120 watt PSU should be fine for that board, provided you're not running a lot of High-current draw peripherals. Would need more info on your setup to say for sure, but the 120w should be fine.