Is it safe to use a meter to test jamma pinouts whilst powered on?

[eggedd2k]

i want to check the voltage of the pins on the jamma connector in my cab. is it safe to do this without frying myself?

[RayB]

Let me ask you something, ... if the power were OFF what kind of readings would you get?

OK OK, partial answer to a mis-worded question. I guess the real answer is it depends if you know what you're doing...

[Navmaxlp]

Voltage on most PCBs are so low that even if you take a shock it won't hurt or be anything to worry about. Trust me on this one hehe. As RayB said, you need to have voltage on to get a reading. Use the "one hand rule" where you place the black lead on a ground and only use one hand to test the voltage. This way, if there are any larger voltages on the board, you'll be safe.  If you do take a shock this way, it will only go across your hand or arm and not across the heart which is the big concern with electrical shock as it can disturb heart beat patterns. Hope that helps.

[SirPoonga]

Voltage on most PCBs are so low that even if you take a shock it won't hurt or be anything to worry about.

Right, your typical jamma psu does
+5v 15A, +12v 2A, -5v 1A
You will feel those but shouldn't be too bad.  Ever touch your tongue to a 9v because someone dared you, we are tlaking shocks like that.  Of course, it depends on what side of the transformer you are "touching" too

it's odd ones like my asteroids psu that has stuff like 24v and 36v.

[monkeybomb]

You will feel those but shouldn't be too bad.  Ever touch your tongue to a 9v because someone dared you, we are tlaking shocks like that.

A dare?  that's just part of my morning ritual.

[Kilgore]

Voltage on most PCBs are so low that even if you take a shock it won't hurt or be anything to worry about. Trust me on this one hehe....

Just be careful and don't electrocute yourself when you bang your head on the monitor as you are crawling out of the bottom of the cabinet.

Now you didn't ask about frying the JAMMA board

[paigeoliver]

I have never gotten a shock out of game wiring or boards, and really, I'm not even careful at all.

I have gotten multiple assorted monitor shocks (ranging from the full charge of a powered up tube, to the standard HV that powers the flyback to whatever other voltages are hopping around on the monitor).

[Druin]

One thing to point out, if you are looking to do resistance/continuity measurements rather than checking voltage readings, power has to be off or you may blow a fuse in the meter.

Resistance/continuity - the meter provides power to the circuit under test.

[ShinAce]

You won't hurt yourself playing with a JAMMA board. However, you may destroy the very board you seek to protect.

At no time, should you allow ANY short circuits. So if you're testing 2 points close to each other on a pcb, and you slip and let both probes touch(even for a split second) you are likely screwed.