Irem M92 minimum voltage level needed

[hardyhell]

Hy guys.

I have some Irem M92 boards and also had a M72.
I noticed that they need about 5,1 volt to run properly and not crash. I assumed it is normal since I read it here somewhere that these boards are power hungry.
So that I now would like to sell it I am looking for some confirmation of other owners that this is totally normal and no fault either the board. Talking in particular here about a Major title 2 board that is converted to R-Type Leo.

Thanks guys.

 

[ekorz]

I have never met a 5v logic chip that prefers 5.1v. They are built for 5.0v and tolerant of a little more or less.

My guess is you are measuring the voltage at the jamma harness, with nothing plugged in, setting it to 5.1v, turning it back off, and then plugging in a pcb. Is that how you’re measuring 5.1v?

Once a power supply is under load, each board draws a unique amount of power. The psu is designed to be adjusted so you can deliver 5.0v exactly to each pcb regardless of its draw. In the above example, if your un-loaded psu was set to 5.1, the system power is probably ending up at more like 4.85v when loaded with an m92 board. That’s operational but poor practice and will wear out the components faster.

So instead you should be plugging in the pcb, then turning on the psu, then measuring voltage at the jamma edge (or a chip in the middle of the board), and dialing that system power to 5.00000000v while it is on.

 

[fuzzbuddy]

I use one of those LED voltmeter JAMMA adapters at the edge to be safe.

 

[djsheep]

I use one of those LED voltmeter JAMMA adapters at the edge to be safe.

They’re great. On larger boards with lots of draw however they loose their accuracy slightly. To be 100% on point, it’s good measure to double check with a multimeter

 

[ekorz]

I use one of those LED voltmeter JAMMA adapters at the edge to be safe.

Those have a little calibration trim pot on the reverse side. I’ve had one or two need an adjustment. But I use them too otherwise. I set it once according to my multimeter, and then trust it for the most part.

 

[hardyhell]

I measured while running the system plugged to the pcb.Am using a multimeter and measure at the Jamma edge of the pcb between the pcb and the Jamma plug of the arcade cab. So the lowest voltage there was 5,05v and the game doing fine through a complete playthrough