Snow Bros PCB Power Issue

[ptom98]

Having an intermittent issue with a Snow Bros PCB where sometimes it doesn't power on.


It I initially had sync issues and audio issues, but resitting the socketed chips, giving it a little clean and replacing the audio amp fixed those.

When it boots up it works without issue, but there's been a couple of instances where it doesn't appear to power on.
I have it connected to a HAS SuperGun, and when this happens the voltage meter on there also doesn't turn on, unplugging from the JAMMA harness and plugging back resolves it, but am concerned that it's the sign of a future potential issue/something I should be concerned with.

I've done some minor repairs on boards before, but not to sure where to start on this one, any advise works best useful

 

[sukhbir]

What power supply are you using?

 

[big10p]

Doesn't sound like your HAS is getting power then, so could be faulty, but more likely the PSU is at fault.

 

[ptom98]

Mean Well RT-125A, I thought it might be the power supply, but this is the only board where I have the issue

 

[Lurch666]

Are you unplugging it when you aren't using the PCB?

 

[ptom98]

When not being used, no PCB is plugged into the HAS but the Mean Well is plugged into the wall socket but turned off.

 

[Lurch666]

What's probably happening is your snow bros has a slightly smaller edge connector than the socket and sometimes it's off enough when you plug it in to short the GND and +5V that are next to each other on a jamma. This would cause your PSU to instantly cut power. When you unplug and then plug it back in you must be fitting it better so it's no longer shorted.

 

[big10p]

I was thinking probably a short somewhere, too. I always check pin alignment when plugging boards in.

 

[ptom98]

I'll make sure to test when i plug it in next

 

[qjuk]

The only other slight issue I can possibly think of that there is not quite enough (or a boarder-line) load on the +5V for the Meanwell PSU to fire up. Snow Bros is a small pcb and I don’t think it draws much.

Often, if there’s a short the PSU will shut down for a while before it will work again which makes me think it’s not actually an issue with how you are connecting at the edge connector.

Edit: If it’s an original Toaplan pcb, the edge connector pins are properly spaced and you shouldn’t be able to accidentally connect it slightly off, unless of course someone has filed down the edges of the pcb or some reason or your JAMMA connector housing plug is damaged at the side/s.