Consolized Naomi won't power off. Micro ATX issues...

[jassin000]

Yea something isn't right at all, I would expect to find current on the 5V line... But 1v on the 12v, and a full 3.3v on 3.3v?!?

Normally I would recommend you just do what I do, use a real JVS arcade power supply like a Sun...
Or, use a Suzo/Happ 130watt JAMMA arcade power supply with a Capcom IO and carts (but don't expect to run a GDROM or DIMM board like this).

 

[nam9]

Hmm... not good. I really like this form factor and I've not experienced any power troubles so far... ... ...
I 've been in touch with Larry over at HDPlex - according to him grounding the PS-On line should switch the unit on and removing ground should switch it back off again... Will see if they have another solution. I could switch the 19v input, but if there is a fault with the PSU itself...

 

[nam9]

So HDPlex asked me to test a couple of things...
1. Check to see if the PSU LED stays lit after 'power off'.
2. Remove the 12v load and retest.

1. Power LED lights up when switched on... and remains lit when switched off...
2. With the motherboard 12v line disconnected the unit powers on and off correctly.

So there is unwanted 1v on the 12v rail to prevent proper shut down.
Let me ask where this 1v is coming from.

Since it can be shut down properly on PC, this 1v might be related to your device.

Would you have any clue?

The only source of power to the Naomi is the PSU... but then... what of the supercap, or CR2032 battery?
Could either of those be the culprit? 1v on the 12v rail doesn't seem like it would be related to a 3v coin cell, or 5.5v supercap... (yes, i have replaced the sc).
Then again, I should be able to measure 1v on the 12v with the psu removed if either of those was to blame?

 

[obcd]

Maybe you could try a diode in serie with the 12V line. I don't think the 12V is very critical. It should still work, even with the diode voltage drop. You could use one of those dual diodes you find in pc power supplies. I am sure your local computer shop has some defective supplies he is willing to give away or sell for a very small price. The diode might need some cooling, depending upon the current that passes trough it. It's back needs to be isolated from the shield which is GND. If it's a dual diode, cable the 2 diodes in parallel.

The diode would block the 1V, so the supply should work fine if it's the issue.

 

[nam9]

Well... to draw a line under this particular problem I have now switched the +19v input that powers the ATX DC-DC converter itself.
I had entertained the idea of somehow using the +5vSB to replace the NetDimm battery, but I probably down't want to leave this thing plugged in with its massive laptop power supply attached.

I am sure you are all relieved to hear that everything is now functioning as intended.

Thanks for all the helpful suggestions!