36 LED theatre lights ?

[BurningTantalum]

I picked up 3 LED light units that appear to be for stage or theatre use.
The outside of the die cast aluminium cases are corroded (I live on the coast) and the maker or model numbers are not legible. I haven't yet managed to free the screws holding the bezel, and this is the only way in. There is a connector for 240V in, which is paralleled to a 240V out connector. There are also connectors for 'DMX' in and out.
Does anybody recognise this light and have any idea what the intended use was/is?
Regards,  BT

[funkyant]

It's a cheap clone of an Expolite Tourled 42. The original is rated IP67 and has 3 in 1 RGB LEDS. The one you have doesn't. Check the manual with exploded views:

http://www.masystems.de/gfx/vermietpark/Lichttechnik/Scheinwerfer/ExpoliteTourLED42CMWP/TourLED42CM.pdf

If they cloned the firmware, you should be able to press MENU, then scroll up to 'STAT', press enter, then test by entering RGB values using up/down and ENTER

[BurningTantalum]

Funkyant- You are a star- thank you!
I have only just downloaded the manual from your link so have not had time to peruse it.
I have managed to get the bezel off one of the 3 units.
It seems that this 'Repair' section is the appropriate place for this query- Inside is a SMP 28V PCB with a big blast mark under the area of the switcher transistor/FET whatever (I can't see it until I remove the heatsink). The inline fuse on the 240V was blown.
There is a separate control and driver PCB which, upon application of 28V DC to the strangely coloured Black for +, Red for -, brought the lights on. The switches on the panel are seized so it wasn't easy to play around with the modes but the whole shebang seems to work fine.
The units do indeed seem to be copies/clones of the Expolit unit, but with 36 LEDs RGB and a bit more of a finned body around the light unit.
I will try to get into the other units tomorrow (CRC into small holes drilled into the casting by the screws)
I will find a use for these- must compete with the neighbours Xmas lights !
I have never come across the DMX control protocol before, so will have a few minutes with Google.
Regards,  BT

[Richard Crowley]

There is a pretty good summary and explanation of DMX here....
https://en.wikipedia.org/wiki/DMX512

[funkyant]

DMX is just RS485 with some fixed variables, eg. baud, parity, stop bits etc.

There are some excellent Arduino DMX projects and libraries if you wish to learn/ play.

[jketterl]

I once managed to replicate a "Digital Enlightenment" DMX interface with an Arduino Leonardo and nothing more but a MAX485 chip. That particular interface is widely supported by lighting software. The software is not exactly simple (it requires a modified Arduino Core library) but if you're interested, I can write up a guide

[BurningTantalum]

Thanks Richard and Funkyant- I am now enlightened (no pun...). The firmware does seem to be the same as the Expolit, I am about to lash up some push button switches to have a play. The lights are BRIGHT !
TSF8N60M MOSFET dead all ways round- I should have something in the drawers.
Jketterl- Thanks for the offer. I am content that I now know of the DMX protocol, but cannot see me getting too far involved with it. I may rig up a controller from proprietary parts just for these light units.

Homer-  "When I learn something new it pushes some old stuff out; remember when I took that 'Home Winemaking' course and I forgot how to drive the car?"
Marge- "Homy, that was because you were drunk..."
Regards, BT

[SeanB]

If the switch device is dead short all the way round then the driver will be blown as well. Check the small electrolytic caps there as well as if they are high ESR the new switcher will have a very short life. High value resistors as well, as they probably are a startup supply for the chip.

[BurningTantalum]

Sean-
One SMPS is up and running with a couple of parallel 0R SMD links, a MOSFET and a bodged on through hole 0R47 source resistor (to replace 5 parallel ones), plus a PCB 3.15A fuse.
One fixed with just a fuse and a MOSFET plus the same 0R47.
The third, as you predict, has a blown PWM type OB2269CP, plus MOSFET and resistors as above.
Thanks for the tip on the caps- I will check.
Regards,  BT

[Khaveer]

You can build a simple DMX interface that can be hooked up to your computer based on the ENTTEC Open DMX USB. There's a lot of schematics on the internet, but it's basically a MAX485 or SN75176 hooked up to a FT232 chip. This device is compatible with many free lighting control programs like QLC+, Freestyler or M-PC.

[BurningTantalum]

Khaveer-
Thanks for that. I will have a look at the lighting control programs, and may make up a DMX link; you have got me interested !
 I have had two lights working over Christmas lighting up the gum trees around here, and am waiting for a replacement PWM IC to get the third light working.
I didn't want to get dragged into another project when I have a big queue on the workbench but... this is how we are, isn't it ?
Season's greetings to you,
BT

[BurningTantalum]

Sorry to resurrect this dead thread but I have a query about the DMX interface (this should really be in the Beginners' section as I have no idea what I am doing !)
I have three working LED spot lights now, and decided to have a play with the DMX interface just out of interest. I found the cheapest USB to RS485 interface on eBay and ordered it (I didn't want to spend too much time getting involved in knocking up an interface...)
I downloaded copies of QLC+ and a couple of other programs and installed them on an old workshop XP laptop.
I struggled to sort out a driver for the interface but finally got a PL2303 driver that 'worked'.
The chip on the interface is a Prolific PL2303 (or clone) with a MAX485.
I cannot get any of the programs to recognise the interface, and the only theory that I have is that they will only work with FTDI chips.
The PL2303 is recognised by name by '232Analyzer' so I assume that the interface is working.
The lights use an SN75176 line driver. Is my theory correct, so do I need to knock up/purchase an interface with an FTDI chip ?
I assume that a MAX485 be happy talking with a 75176 ?
Regards, BT