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LK204-25PC gpo problems :(
Posted: Sat Oct 05, 2002 5:25 pm
by MASK666
If hooked up my cold cathode to any of the gpo's it flashes on and then goes off(it will only do this every time I trigger the gpo on).. If I hook it to a standard molex it works like a champ... I have a 450watt enermax PSU any not power hog stuff going on like a water rig... I have checked my wiring over and over again and the only thing left to do is mount the lcd... Hell If I want to mount it then find out the gpos are bad and it needs to be returned..
Thanks
Posted: Sun Oct 06, 2002 7:59 pm
by Henry
Your cold cathode, how much current is it drawing? and how much voltage does it require? have you tried multiple GPOs?
Posted: Sun Oct 06, 2002 8:15 pm
by linear
How about an LED? will the GPO drive an LED?
Posted: Sun Oct 06, 2002 8:24 pm
by MASK666
It will drive a Fan or a LED yet the Cold cathode will only blink once. I have not heard about people using multiple GPOs on the ligths, but I would like to know a little more so I might try it. Also, how much current is each GPO rated for again? As far as the cathode goes I know it requires 12volts but at this second I am not 100% sure what the current is.
Posted: Sun Oct 06, 2002 8:34 pm
by Henry
We say the GPO will do 750mA officialy, but I have tried it up to 1100mA.
Posted: Mon Oct 07, 2002 12:56 am
by Stig
I think a typical CC is 3W, so that is 250mA. I also have problems with my CC connected to GPO1. I normally have to turn it on and off several times before it comes on. I thought that it was the CC, but maybe it is the GPO? I haven't measured anything yet though.
Stig
Posted: Mon Oct 07, 2002 5:26 am
by MASK666
Do you turn the gpo on and off or the lcd itself to get it working?
Posted: Mon Oct 07, 2002 7:07 am
by linear
Since it's working normally with fans/LEDs, I'd suspect that the GPO can't deliver the inrush current your CCFL inverter is wanting to draw.
I haven't checked out the transient current myself, and inverter designs will differ, but it seems intuitive that an inverter will draw a little more current at startup, since most of them operate in flyback mode, and it takes a fair amount of enregy to build up the magnetic field in the transformer windings.
You could try a different inverter (easiest) or driving it with a power transistor (cheapest).
Posted: Mon Oct 07, 2002 7:16 am
by Stig
Mask666. I turn the GPO on and off, maybe up to 5-6-7 times before it works.
Strange thing is that I don't have any problems with the CC on GPO2. I also have a CC that I'm going to put on GPO3, sp maybe I have to install that soon and test it...
Stig
Posted: Mon Oct 07, 2002 7:21 am
by nikko
GPO = General Purpose Output ???
Posted: Mon Oct 07, 2002 7:23 am
by Stig
Yep.
Posted: Mon Oct 07, 2002 7:24 am
by nikko
what are the GPO
Posted: Mon Oct 07, 2002 7:42 am
by Stig
You can use them for whatever you want...
On the LK204-25PC, which has 12V outputs, you can control fans or CCs directly. The other displays have 5V outputs, so you can control LEDs (for example to show if you got mail) or relays (for example to control fans or your room's lighting).
Stig
Posted: Wed Oct 09, 2002 1:49 am
by Stig
Installed the third CC yesterday and put it on GPO3 and had exactly the same result as Mask666. It came on for about half a second, then turned off. But it obviously drew too much current because at the same time the whole display dimmed. Hmm, guess I have to make some driver-thingy for it...
Edit: Just noticed that GPO4 turned on at the same time as GPO3 was on, i.e. about half a second. This is on the "old" 25PC display.
Stig
Posted: Wed Oct 09, 2002 10:10 am
by Henry
We really need to see how much current the CC draws in rush...