[Titaniumboy]

Hello,

I just received my UC300ETH and the 5LPT motherboard along with the UCCNC software. I am installing it to replace a demo version of Mach3 in a 2014 Novakon Torus mill that has a Windows7 motherboard feeding a Novakon breakout board via parallel port.

The Novakon factory panel uses a 400 watt power supply to feed the Windows7 motherboard and the breakout board. This power supply has tons of extra leads and connectors, usually with both 5V and 12V available.

My question is where to safely obtain the 5V to power the UC300ETH. Can I simply use one of the spare leads from the power supply and grab the 5V and GND from there?

[dazp1976]

My question is where to safely obtain the 5V to power the UC300ETH. Can I simply use one of the spare leads from the power supply and grab the 5V and GND from there?

Honestly I would use a seperate small 5v supply myself.
You know the board is then kept isolated.

[OlfCNC]

Ethernet is isolated if you will use the computer power supply then you will have no isolation anymore.

[Titaniumboy]

dazp1976 and olfCNC,

Thanks for the replies. I was afraid you guys were going to say I needed a separate power supply.

Does this fit the bill? Meanwell RS-15-5. 5V 3A from Amazon for $12.49?

https://www.amazon.com/MEAN-WELL-RS-...ct_top?ie=UTF8

[Titaniumboy]

I bought the little Meanwell power supply mentioned in my last post. I finally got the power supply and UCCNC UC300ETH board installed. I applied 240 VAC to the power supply input and left the 5VDC wires unconnected to the UC300ETH .board.

I measured the power supply output at 5.1 VDC, which seems OK.

I then decided to switch my multimeter to the Volts AC scale and I measured a whopping 10.3 Volts of AC. What the heck? Thank goodness I decided to check the AC and DC voltages before connecting the PS to the UC300ETH.

I verified these results with a second multimeter. I should mention that both multimeters are very very inexpensive meters.

Is it just a case of having bought a lemon power supply, or do all these power supplies do this? The Meanwell spec says 80mv of ripple...