Debugging my MV-1C console build

I have a MV-1C board hooked up to a retroelectronik supergun board and a jrok video encoder. At first I wired up a standard jamma power supply from china but it made a terrible noise and my multimeter claimed it was outputting almost no power. Plugging in a PC power supply to the ATX connection without unwiring the jamma supply from the board I got it booting with all my carts except the 161-in-1, and played a few rounds of samsho3 with no issues. I then proceeded to change a few jumpers to get free play, then unwired the jamma supply as I deemed it useless and try to restart it. Ever since then, I have gotten a static screen with squares when booting with a cartridge in http://imgur.com/a/ZlJDe

and just staticy flat colors which start gray then cycle to staticy red. I'm net getting resets, nor can I seem to ge to the debug with jumper 1 on. I've tried booting jumpers all on and all off to get some debug screen up but it never gets that far.

I'm assuming this is something crazily power related but I gave up last night before I could really dig in with the multimeter and honestly I'm not sure were to start. One more thing, the jrok looked terrible with the jamma supply hooked up, and perfect without it hooked up so I assume something fishy is going on related to having that jamma supply in the mix.

Thoughts??

 

So taking a multimeter to it I see that I'm def not getting enough juice:

With a cart in, no jrok, no jamma supply, just ATX, I show 4.1 volts
With no cart, no jrok, no jamma, just ATX, I show 5.15 volts and get a grid
With no cart, jrok, ATX, I show 4.95 volts and get a grid

Different carts show different volt readings, and the 161-in-1 seems to draw the most power, whereas samsho3 is my test cart above.

HOWEVER, if I attach the jamma supply AND the ATX and let it roll a bit, I can get it to boot - so I guess the jamma supply is storing a bit of power and helping out

SO! What power supply with straight PC style ATX plugs will work best for this set up and actually power my jrok, board, and 161? And why is this PC power supply incapable???

 

Hm, what PSU do you have? It could just be faulty as well, but may not have enough amps on the 12V rail to power the unit.

For a replacement, this would work great. 130W is not the actual wattage, 350 is and the seller is just smoking something.

http://www.ebay.com/itm/Seasonic-SS...578500?hash=item41b9f2e8c4:g:r8QAAOSwEzxYUtk6

 

This is what I have on there now: http://imgur.com/a/xdyHM
It worked last time I had it attached to a PC

 

Oh wow. Yeah, that PSU shouldn't be having problems with power, the Hive are relatively new and good units. Is the MV1-C board defective? I were to hope not...

 

How would a defective board cause the symptoms I'm seeing from my multimeter?

 

A friend told me it's not sending enough amperage but then was very confused when I showed him the power supply I'm using.

 

Yanking out both controller adapters gives me enough power to boot samsho1. 5.1 volts. Plug in a single controller and it boots a bit then dies over and over. 4.65 volts on that case

 

Try with a different power supply if you have one available to rule out that that one is bad. If the behaviour is the same with another power supply and you have such a big voltage drop on such a powerful power supply you ought to be able to feel that some components are hot to the touch (turn off the power before you feel around of course).

 

SOLVED! tldr; Don't use a pc power supply for your arcade needs - use an arcade power supply.

PC power supplies need a certain draw on the 12v rail to regulate the 5v properly - even new ones.

Removed the ATX supply, and put in a straight arcade style DC power supply with +5 and +12, and adjusted it properly with my multimeter, and EVERYTHING works perfectly everytime and it is beautiful and all is right with the world. So! If you're not booting and getting blocks of color, or getting straight color screens with static, check the power at the test pads above the word JAMMA on your board, and you'll probably find low voltage

Thanks everyone for the help! <3 I'm super happy right now

 

You could easily fix this with dummy load if you still want to use the power supply. You basically just need a big resistor that can radiate a bit of heat and solder it to your supergun in parallell from +12 to gnd.

edit: come to think of it, you could just modify one of the molex power cords that comes out of the PSU, cut the cable down to a little over the plug and put the resistor there.