99benns Posted November 5, 2009 Share Posted November 5, 2009 Hello I'm not sure if this is the best place to post a question regarding a broken item... Basically I purchased 8 cheap chinese OEM 10mm LED par 64's from Thomann, I needed something a little brighter than 5mm and didnt really have any money to spend and needed them urgently so that was that. When testing them, there was some power surge from the mains, all the other lights in my rig were fine but I can no longer control these new fixtures by DMX. The stand-alone preset fades and colors all work fine but none of the fixtures respond to DMX at all. I'm yet to use these in a gig, Thomann aren't replying to any of my e-mails so now I'm stuck with 8 broken lights. Does anybody know of a site where I may be able to get some help fixing these? As they are a cheap OEM it's impossible to find any information on these online. The processing chip is a pic 16f767-14. I've changed the chip on the DMX input (TI SN65LBC184D volage suppression) with no luck. Perhaps the DMX inputs of the PIC are bust? If I change the pic itll need reprogramming though, and I wouldnt know how to do that! So any suggestions? Thankyou Simon Link to comment Share on other sites More sharing options...
simschr Posted November 5, 2009 Share Posted November 5, 2009 I had a problem with one of the PARs I received from Thomann, being unable to control by DMX I called them and they sorted it me out with a replacement. I would try calling them. Chris Link to comment Share on other sites More sharing options...
99benns Posted November 5, 2009 Author Share Posted November 5, 2009 I had a problem with one of the PARs I received from Thomann, being unable to control by DMX I called them and they sorted it me out with a replacement. I would try calling them. Chris Yeah I'll give it a try tomorrow. The problem I have is that all 8 fixtures are broken, I've chopped off the european connectors and I was stupid enough to tell them I experienced a power surge Link to comment Share on other sites More sharing options...
KevinE Posted November 5, 2009 Share Posted November 5, 2009 Its strange why this would happen, and knock out all the PIC micros in the same way and just affect the input that talks to the DMX tranceiver. Have you doubly checked you're not doing something wrong or there's some weird setting been altered or glitched in the controller? Try doing a fac reset on the controller, and try again just connecting one parcan to the controller. Make sure you have the correct polarity of DMX since this 'standard' is anything but. Did you ever have them working on DMX? How did the surge happen? Link to comment Share on other sites More sharing options...
99benns Posted November 5, 2009 Author Share Posted November 5, 2009 Its strange why this would happen, and knock out all the PIC micros in the same way and just affect the input that talks to the DMX tranceiver. Have you doubly checked you're not doing something wrong or there's some weird setting been altered or glitched in the controller? Try doing a fac reset on the controller, and try again just connecting one parcan to the controller. Make sure you have the correct polarity of DMX since this 'standard' is anything but. Did you ever have them working on DMX? How did the surge happen? Yes I had them working no probem at all at first. I'm pretty sure the live got bridged with the gnd and consequently shorted down the gnd DMX pin because it killed my DMX controller too. One of the fixtures in the chain (maybe the first connected to the power) is more damaged than the rest and has black marks on the PCB around the DMX input. All my other lights (scanners and other brands of LED par) were absolutely fine Link to comment Share on other sites More sharing options...
timsabre Posted November 5, 2009 Share Posted November 5, 2009 Its strange why this would happen, and knock out all the PIC micros in the same way and just affect the input that talks to the DMX tranceiver. Have you doubly checked you're not doing something wrong or there's some weird setting been altered or glitched in the controller? This is actually quite a common thing to happen. The DMX transceiver gets zapped and the zap sometimes passes through to the micro via the tx or rx pin, killing those pins too.More expensive gear has protection on the DMX lines to help avoid this. If changing the DMX chip doesn't fix it, it'll have to be back to the dealer - even if you could change the PIC you will not be able to get the software to program into it. Tim Link to comment Share on other sites More sharing options...
99benns Posted November 5, 2009 Author Share Posted November 5, 2009 If changing the DMX chip doesn't fix it, it'll have to be back to the dealer - even if you could change the PIC you will not be able to get the software to program into it. Tim Yeah that's what I was thinking. There may be a small chance I could read the code from the chip however I'm assuming they have blocked it, even just getting the pic number was difficult as they have attempted to scratch it off (however looking at 4 fixtures I managed to piece together the number). So is there a DMX chip seperate from the pic? I can't seem to see one Link to comment Share on other sites More sharing options...
timsabre Posted November 6, 2009 Share Posted November 6, 2009 You say in the 1st post that there is a SN65LBC184D. That is the "DMX chip". It's an RS485 bus transceiver. You will not be able to read the pic, they will certainly have locked it or it's just too easy for the factory down the road in China to clone the product. Link to comment Share on other sites More sharing options...
gyro_gearloose Posted November 6, 2009 Share Posted November 6, 2009 If you fancy a little project, you could always make some of the LED DMX controller circuits that I posted a while ago. Have a look here. Link to comment Share on other sites More sharing options...
KevinE Posted November 6, 2009 Share Posted November 6, 2009 Yes the parcan micros are all copy protected, been there, done that! Thomanns own brand (stairville) used to use Atmel AT series micros but must have swapped design or factories because the latest ones I've seen are larger Microchip PICs. This is actually quite a common thing to happen. The DMX transceiver gets zapped Yes, indeed but he said he'd had a 'power surge'. When testing them, there was some power surge from the mains Putting mains down the DMX makes a whole load of difference and isnt what I'd call a power surge! To me, power surge means a momentary higher voltage on the mains inlet which in the case of the Thomann parcans would've been unlikely to have got past the mains transformer and 7805. Do you know what actually caused mains to go down the DMX line? If this has happened then I'd put it down to experience unless Thomann are in a sympathetic mood! Dont worry about cutting the euro plugs off, this in itself doesnt void the warranty. Link to comment Share on other sites More sharing options...
timsabre Posted November 6, 2009 Share Posted November 6, 2009 I've seen a lot of blown up DMX chips and they are nearly all caused by a mains fault or earthing problem. We are not talking about feeding mains down the DMX line here. For example a live to earth fault can kill DMX chips, because this can cause a voltage spike on the earth which causes a high common mode voltage on the DMX line (ie between data+/- and signal ground). Link to comment Share on other sites More sharing options...
KevinE Posted November 6, 2009 Share Posted November 6, 2009 Do we know how the internal electronics in the cans actually got referenced to earth then? The thomann cans use an isolating transformer to supply the board thus the electronics are floating (rather than opto isolated). They also use insulated XLR ins/out connectors. Perhaps mic leads with earthed XLRs were used and 2 or more shells simultaneously touched earth or an earthed lighting bar at the same time as an earth fault occurred? Maybe Simon can say exactly what happened. http://www.k-edwards.co.uk/images/par64.jpg This is a pcb from the early cans, the green connector on the right is from the 12V transformer, the DMX connector goes to the panel with XLRs on, the large JST connecotr goes to the LED pcb and the small one to the speed/sens/mic pcb. The later boards are a little bigger and a bit rejigged. Link to comment Share on other sites More sharing options...
99benns Posted November 10, 2009 Author Share Posted November 10, 2009 OK basically I've found out now there was no power surge. I had left the lights with 2 other guys who were testing them and fitting the plugs, one of them wired the live to the ground on one of the fixtures. great. <_< The LED driver and the control circuit seem to be on seperate circuits. There are no large components on the top circuit, just a 3 small capacitors, the pic and a couple of small chips and resistors. From the help everyone has given me here, it seems as though the most likely problem is that the DMX inputs on the PIC are dead and a possible solution would be to replace the PIC with a new programmed one. I would really prefer not to have to learn how to program my own DMX into the pic or build a new circuit myself (as fun as it would be, and I have a couple of arduino boards knocking about from past projects but I don't have so much time anymore!)...can anybody suggest any alternative solution or am I simply going to have to return the units to the manufacturer and pay for a repair (if it doesn't cost more than the £47 per fixture I originally paid!). Thanks again for everyones help Link to comment Share on other sites More sharing options...
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