Question about NSI dimmer pack upgrade

[JohnA]

Greetings to all,

I am looking to upgrade several NSI DDS 6000 packs from microplex to DMX protocol. I know this has been covered before, but I could not find a direct answer in my forum search. So, if anyone has a link, feel free to provide it.
I have a call in to NSI tech support & am awaiting a reply--but have tentatively been told "you can't just put an rs485 chip in there". I am finding that a bit hard to believe, since I know the chip is not an EEPROM.

BTW-I would appreciate a straight forward answer, avoiding (-) comments or opinions on the NSI line.

Thanks for your time--John A

[church]

All an RS485 chip does - depending on which chip is: is transmit, receive or both transmit and receive RS485 signals. The problem is those signals have to be in the 16 bit dmx format and you have to have an address decoder circuit to recognise which group of commands are for the dimmer unit and then convert the commands to the format required by the dimmer.

[JD]

Much of the NSI line has dual compatibility, but certainly not all. Microplex is its own format and is different than DMX. You may have to go to Doug’s site and get a translator.

[JohnA]

Thanks for your replies. Per NSI, the DDS line is DMX ready. All I need to do is get an RS 485 chip & plug in & attach the leads to the dedicated bus located behind the DMX socket.

[dramatech]

The chip you need is a 75176. It may have some letters in front of it depending on who manufactured it. It will be an 8 pin DIP, that is four pins on each side. There will be a little dot over pin one or a a little dent in the end where pin one is. Most circuit boards will have a drawing of the chip with the dip printed on the board. Make sure that you line up the dent on the chip with the dent indicated on the Printed circuit board. On the side of the board will likely be three pins that will receive a header socket. The pins will probably be labeled 1,2,3. It is pretty straight forward pin 1 on board goes to pin 1 on an XLR socket and the same with the other two pins. As 5 pin XLRs are the standard for DMX, although many lesser expensive devices use 3 pin, you should use the five pin as the microplex on the dimmer pack will have a 3 pin and you don't want to confuse the two. Five pin XLR connectors are pretty expensive from Switchcraft and Neutrix, but Pomona XLRs are much less expensive and of similar quality. The chip and connector are available from mouser.com. There is no minimum order, but UPS ground will be as much as the components. You may want to order mic connectors, 120 ohm resistors and additional 5 pin DMX to make terminators or whatever in order to justify the shipping charge. And by the way the chassis mount connector for DMX in, on the dimmer pack should be a male connector.

[jreckart]

So, has anyone just added the chip and header and it worked?

[mrb]

Originally Posted by jreckart

So, has anyone just added the chip and header and it worked?

ive done it to several consoles, and i think I did a dimmer but it was so long ago im not sure. I seem to remember the chip for the console being a max485, i dont know if the pinout is the same as a 75176 or not.

[church]

the pin out is the same. I use DigChip IC database for quick access to datasheets.

[BillESC]

A5512-000 is the part number for the DMX conversion kit. MAP price for it is $ 103.95

[JohnA]

My NSI DDS6000's took the MAX485 chip with no problem. Total cost--a couple of bucks.