Fusing DC lines

[RayB]

Does someone have a tutorial on fusing the DC power lines (5v and 12v, etc) ? Bob Roberts' wiring pages are great but don't mention this part at all. Now, I can understand that maybe it's not necessary, but I've seen first-hand evidence to the contrary (had a 12v line fuse pop in a jamma cab).

Now, I know what you're thinking, "just copy what your jamma cab has set up, stupid!" but I want a reference to compare recommended fuse ratings, just in case what's in my jamma cab now is not right.

[grantspain]

what you need to do is set your multimeter to amps,cut the +12 wire,put the multimeter in line with the +12 wires and see how much current your machine is drawing,then you can match a fuse to that current

[Ed_McCarron]

Or, look at the current rating of the power supply and the listed current draw of the board.  Size fuse between the two.  Since I doubt theres a comprehensive list of board current draws, I'd probably err on the side of caution.  Start low.  If it blows, upsize.  Stop before you reach the amperage of the power supply.

That way, then the board shorts, the fuse opens, and you can burn your house down with an undersized freezer extension cord instead.

[RayB]

We're talking JAMMA here. Shouldn't it be standard?

[SirPeale]

We're talking JAMMA here. Shouldn't it be standard?

Kinda.  Well...no.  It all really depends on the equipment involved.  JAMMA is a "wiring standard" which means that you can plug any JAMMA board into any JAMMA harness and the controls and monitor hookups "should" work.

For example, my Atari Tetris board is JAMMA, but I know darn well that Blitz with it's huge board, graphics card and hard drive are pulling a lot more juice than that is.  Hence I'd want a larger fuse.  Personally, I'd go with a 2A slow blow fuse.  If it draws more than that likely it would be sudden and you'd want the fuse to blow.  Though I'd still do as suggested and use the amp feature of your multimeter.

If your multimeter doesn't have the amp feature, I know one that does. 

http://www.pealefamily.net/arcade/store/index.php?main_page=product_info&cPath=3&products_id=15

[Wade]

I've never seen the DC fused, just the AC on the whole cabinet.  Every DC switching supply I've had would just shut down if there was too much load, it wouldn't burn wires or anything.  If the whole supply took too much power the AC cabinet fuse will blow.  Keep it reasonable at 2A or so and you should be fine.

Wade