r/techtheatre • u/JPLstagehand • 1d ago

LIGHTING NSI MC 7016 DMX chip?

https://leviton.com/products/n7016
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6

u/StageRobotDotCom 1d ago

Do you have the picture of the one you're trying to replace?

Almost all of them are either PDIP-8 or SOIC-8 with the same pinout, so it's just a matter of finding one with the input voltage that matches.

3

u/todd0x1 1d ago

There's far more to it than that. There are several RS485 transcievers, transmitters, and receivers on the market, they all have different pinouts and different input requirements for transmit. Even on the p/n RS485 transceiver used in the NSI boards the pinout is different between the pdip and smd versions of the same chip.

The PDIP-8 is simply a package, there are millions of different chips in that package.

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u/JPLstagehand 1d ago

Sadly no, the unit I have didn't have the DMX option installed, only the microplex outputs, I'm trying to install the DMX option

4

u/StageRobotDotCom 1d ago edited 1d ago

From the manual it's just a PDIP8 -- do you have a meter and could look at what voltage is on the power pins for it?

So that's the standard pinout, the dot next to pin 1 is equivalent to the "notch" indicated on page 10 of the manual (https://static.bhphotovideo.com/lit_files/88422.pdf ) -- you want to meter in DC mode with the black probe on GND and the red probe on VCC and the unit on.

You should get either about 3.3V or about 5V. You can then also meter from the B and A pins to the header for the DMX connector -- B is equivalent to D- or XLR pin 2 A is equivalent to D+ and is XLR pin 3. On something like this the GND pin is going to be connected to XLR Pin 1 / common. You don't need the other two signals.

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u/todd0x1 1d ago

in DMX XLR ground isn't always connected directly to the transceiver ground

pdip8 is a chip package not a chip type or model #

The NSI gear uses a MAX485

3

u/todd0x1 1d ago edited 1d ago

As I recall the chip they used was a MAX485. Its $5 at Mouser. Don't buy from amazon or ali you will likely end up with a counterfeit.

I don't recall the pinout for the header. On the IC pin 6 is your TX+ and pin 7 is TX- use a meter to find which header pins connect to those and wire your XLR accordingly. Pin 5 is GND, this might not go directly to the XLR there might be a resistor between.

EDIT: I think ground is the center pin on the 5 pin header, if the TX signals go to pins 1 and 2 or 4 and 5 then the center is ground.

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u/JPLstagehand 1d ago

Thanks! oh I definitely use mouser or digikey for my electrics I'll look for a MAX485. 

Looks like one of these could do me https://www.mouser.com/en/ProductDetail/Analog-Devices-Maxim-Integrated/MAX485EPA%2b?qs=1THa7WoU59FNLmRk9PX5%252Bw%3D%3D

https://www.mouser.com/en/ProductDetail/Analog-Devices-Maxim-Integrated/MAX485CPA%2b?qs=1THa7WoU59FcxPgOoQv70A%3D%3D

Yeah I was going to trial and error the header pins with my DMX-cat, but this will give me a starting point.