PC shuts down after booting for a few seconds with p1900

**DarkStar02** · 02-10-2007, 04:02 AM

Hi all. I

but it doesn't have a solution for this. When the ignition wire is switched, the PC starts up for a few seconds then shuts back down. However, if I just touch the two wires that I soldered to the power button together, the circuit shorts and the power turns on.

Pics from my worklog.

edit: this is with a dell cpx laptop and a carnetix p19000

**HDTechnology** · 02-10-2007, 09:25 AM

your problem may be your startup shutdown controler, in my opinion, i could be wrong so listen out to others advise.

it looks like your controler is "pushing the button" per say for too long, hence it starts up then shuts down. Try this just to compare situations. instead of touching the wires together and then releasing w/o the controller. hold the wires together for more than 5 seconds. this usually forces the computer to hard shutdown.

If holding the wires together is exactly the same as the problem your having, post back and we can further try and isolate it.

of course another possibility is bad wiring jolting current through the IGN wire, however if this was the case, it would turn on and off, on and off completly at random. so do a bit of testing and write back. if ya fix it still let us know.

**DarkStar02** · 02-10-2007, 01:27 PM

That is the problem (The top one, holding it down for too long). What should I do?

**DarkStar02** · 02-11-2007, 02:37 AM

bump

**ephyouckay** · 02-11-2007, 02:49 AM

what do you mean by the top one is holding it down too long?

the p1900 only send a pulse, no?

doesnt it send a short circuit and then once it starts up, it no longer continues to send that short circuit?

could be the p1900 is defective as it doesnt stop sending the short circuit signal.

i would try emailing mike @ carnetix or post on the carnetix forum.

DIGItonium · 02-11-2007, 03:16 AM

The pulse shorts the signal pin to ground momentarily. If it's stuck grounded, then the debounce gets defeated.

**HDTechnology** · 02-11-2007, 09:14 AM

if holding the wires together is exactly the same as pluging the power supply in, then i would assume that instead of it pulsing, its sending a constant suppy of power, if it was continually pulsing it would be turning the pc on and off, on and off all the time.

However i have not designed it, this is purly theoretical. I dont know how these are designed so if someone has a better theory

**DarkStar02** · 02-11-2007, 01:18 PM

it pulses, but the pulse lasts for like 5 seconds so that it starts the 'puter up then shuts it back down. What should I do?

**HDTechnology** · 02-11-2007, 01:35 PM

ahh crap, i understand the problem now but im gonna have to sit on that one. anyone got any ideas how to speed the timer up so it dont last as long?

ill try and think of something but thats a tough one for me.

Have a look in bios and turn off a setting somewere that options saying something like. hold down power button for 5 Sec and immediate off. and try switching it to imediate off. I have no idea if that will work but worth a try if its simple.

**DarkStar02** · 02-11-2007, 07:45 PM

Originally Posted by HDTechnology

ahh crap, i understand the problem now but im gonna have to sit on that one. anyone got any ideas how to speed the timer up so it dont last as long?

ill try and think of something but thats a tough one for me.

Have a look in bios and turn off a setting somewere that options saying something like. hold down power button for 5 Sec and immediate off. and try switching it to imediate off. I have no idea if that will work but worth a try if its simple.

I don't have that as an option. Any other suggestions?