I disconnected motherboard from power supply then it won't turn on, but when PC is ON I got 12.05V and 5.08V from the yellow and red wire on HD connector.
I monitor the continuity on J7 PWR-SW, when I turn on the IGN switch, there's no sign that J7 is shorted, maybe my Opus is bad?
It looks like it's working now on my test bench but I'm really confused. From Dell Dimension 4550 user manual it says:
The options are S1 or S3.
AC Power Recovery
Determines what happens when AC power is restored to the computer.
* Off (default) — The computer remains off when AC power is restored.
* On — The computer starts when AC power is restored.
* Last — The computer returns to the AC power state existing at the time
that AC power was lost.
So I should be setting S3 and Off for the above two settings, but I changed it to S3 and On and now it's actually turning on or resume my PC and hibernating when I switch off IGN.
What's going on???:confused:
i have this psu. its fine. what size cable do you have going to the power. have you calcuated your power req properly. iv got 4 guage wire to mine. i think the pc powers up. it sucks juice. and then shuts down because of the thinness of the wire. cig liters arent really a good source for power supplies. also read the manual. you may have some jumper setting wrong
Talked to Opus support about this problem and we went through couple tests to verify the Opus is ok and functional, voltage check on all input/output wires but still couldn't get a final conclusion. The only thing left now is to check if Dell dimension 4550 is ACPI version 2 compatible or not.
Msun, did you ever find a solution to your problem?
No actually I just use it as-is for half year now and it seems fine. I never found out whether the Dell 4550 is ACPI version 2 or not since Dell's support doesn't know either.
Besides PC turns on by itself when I connect the battery, it starts up and hibernates normally when I turn the key on/off. AC Power Recovery is set to "ON".
Interesting. I've been having the same problems with a Dell 8200.
So the only thing you changed to make it power on is to set AC Power Recovery to "On"? I'll give that a shot.
Cannot believe that after 6 years I'm actually benefit from my own post 6 years ago.
The CarPC ran fine for 6 years and finally gave up because the motherboard has 4 capacitors exploded. I had two Dell 4550 and I used the other one as my linux server so I retired my linux server and use it to replace the dead motherboard in the car. Tested everything on workbench with a PC PSU which worked fine, with BIOS set to S3 and Off, move it to the car then the same weird thing I experienced 6 years ago happened again, it hibernates fine but just won't power up right, fan spins for a split second then shuts off. Tried S3 + Last and S3 + Off and nothing worked. I have been puzzled for the last two weeks because I thought it would be an easy swap. Until I find my own post from 6 years ago..... God bless this forum :)