Discostu73 Posted October 7, 2018 Share Posted October 7, 2018 I have a pulsar datapak 18x10A which has a fault. The outputs all slowly dim to 100% although no input protocol is present. I have given the unit an analogue input which is present and controlling the output as expected until the channels all come up to 100% again. I assume this is therefore a fault on the digital input side? The truth is I am only using this unit in my garage to control some old retro disco and nightclub lighting. I would like the datapak to work as it is intended, but I could still make good use of it in analogue control only if anyone knows how to disable the DMX side? I am a bit of a geek when it comes to all the old retro gear from the 80’s and 90’s but am new to posting on forums of any kind. Thanks in advance for any help. Link to comment Share on other sites More sharing options...
musht Posted October 8, 2018 Share Posted October 8, 2018 I have a pulsar datapak 18x10A which has a fault. The outputs all slowly dim to 100% although no input protocol is present. I have given the unit an analogue input which is present and controlling the output as expected until the channels all come up to 100% again. I assume this is therefore a fault on the digital input side? Analogue side is more likely to give issues, digital side will work or it won`t. Slowly ramping up sounds like ground refernce on analogue input might be suspect, (something charging and bringing it up?) connecting an anlogue control might be pulling it back down. Link to comment Share on other sites More sharing options...
timmeh2 Posted October 8, 2018 Share Posted October 8, 2018 Hi Have you tried turning preheat on and off? All the bestTimmeh Link to comment Share on other sites More sharing options...
Peter18 Posted October 8, 2018 Share Posted October 8, 2018 Just to confirm, do ALL 18 channels slowly fade up to 100% together after a while? Only there is a test setting accessed from the dip switches on the main pcb that gives a test pattern where each channel in turn fades up and down. It might be worth seeing if this works as intended and then what happens when it is switched off. Link to comment Share on other sites More sharing options...
R Collins Posted October 8, 2018 Share Posted October 8, 2018 If all channels are floating up then, you have lost the zero volt crossing pulses, which creates the ramps for dimming.Which the opto transistor cct's by the 3 phase input Link to comment Share on other sites More sharing options...
Discostu73 Posted October 16, 2018 Author Share Posted October 16, 2018 Thanks for all the replies, I have tried switching the pre heat in and out but no better with either. Also I have tried the dip switch settings on the overide section, again no better. All 18 channels are slowly ramping up to 100% upon switching on of the electronics. If I give an analogue input on any channels then these are shown on the output side until the fault slowly takes over and overides the entire output to 100% The analogue fault as apposed to digital does make a lot of sense giving it some thought. I have poked about with a multimeter to check for correct control voltage etc. How easy is it to check the transistors mentioned? I wrongly assumed that answers to my original post would be seen in my emails, so apologies for my late reply. I really am very grateful for all your help! Link to comment Share on other sites More sharing options...
R Collins Posted October 16, 2018 Share Posted October 16, 2018 The fault is there are no mains sink for the ramps, the mains neutral is missing, if you are running it single phase all the links for the neutral need to be linked,the live in put needs to be linked. On the lid there three ways show to wire the mains input, star, delta three phase and single phase, if the links are missing there's no reference Link to comment Share on other sites More sharing options...
Discostu73 Posted October 16, 2018 Author Share Posted October 16, 2018 Thanks for all the replies, I have tried switching the pre heat in and out but no better with either. Also I have tried the dip switch settings on the overide section, again no better. All 18 channels are slowly ramping up to 100% upon switching on of the electronics. If I give an analogue input on any channels then these are shown on the output side until the fault slowly takes over and overides the entire output to 100% The analogue fault as apposed to digital does make a lot of sense giving it some thought. I have poked about with a multimeter to check for correct control voltage etc. How easy is it to check the transistors mentioned? I wrongly assumed that answers to my original post would be seen in my emails, so apologies for my late reply. I really am very grateful for all your help! So in my eagerness I have had a look and think the component that could be an issue is a triac/transistor 78M05 based on advice alone. This is a fairly cheap component, but is it as easy to replace as it looks? Also what would have caused it to fail and could this issue still be present? Is it worth replacing this component? Is it’s failure something I could test with a multi meter? I am a qualified electrician with a reasonable grasp on electronics but any advice will be more than welcome. The fault is there are no mains sink for the ramps, the mains neutral is missing, if you are running it single phase all the links for the neutral need to be linked,the live in put needs to be linked. On the lid there three ways show to wire the mains input, star, delta three phase and single phase, if the links are missing there's no reference I am running the unit single phase, all neutrals and incoming phases are linked out correctly. The test lamp connected to the output is illuminating showing that a neutral is present at the neutral links. This doesn’t necessarily mean that a neutral is getting to the control side though? The control is obviously extra low voltage AC judging by the power supply which all seems to be correct when I tested this (clutching st straws!) at what point will mains neutral be used in this circuit? And where could this have been lost? Link to comment Share on other sites More sharing options...
KevinE Posted October 16, 2018 Share Posted October 16, 2018 the component that could be an issue is a triac/transistor 78M05 Neither, it's an IC linear regulator. Multimeter on dc volts, measure across the middle and right leg, you should get a steady 5Vdc. Link to comment Share on other sites More sharing options...
Discostu73 Posted October 20, 2018 Author Share Posted October 20, 2018 Thanks for all the help and advice. I have cleaned and double checked all neutral connections, there is a phase and neutral link which goes to each section of six dimmers which visits the appropriate phase present neon indicator first so I know that the neutral is present. I have also tested the device mentioned above and the 5v is present between middle and right hand legs. The fault still remains. I am learning as I go a bit more about how these things work but still not having any luck. In my mind it must be an input protocol issue to effect all 18 channels? Inside the unit there is an amount of what I think is smoke machine residue, so perhaps one of the main I.C’s is corrupted? I will keep trying and posting back until I have to give up! Any ideas or advice will be gratefully received and tried. Thanks again. Link to comment Share on other sites More sharing options...
ianknight Posted October 20, 2018 Share Posted October 20, 2018 I know this will sound a bit radical but did you try phoning Pulsar? I've had issues with some of their older kit in the past and they've always been happy to offer advice as to potential problem area's to look at (and they used to repair some kit - not sure if they still do). Whilst they don't have the high visibility of other UK manufacturers of this type of kit - they do have lots of legacy kit out there and will help as far as they're able - they might even be able to send you circuit diagrams. Link to comment Share on other sites More sharing options...
gyro_gearloose Posted October 20, 2018 Share Posted October 20, 2018 I thought Pulsar were no more. I’m glad to say that I was wrong about that. Not only do they still exist, they can help with fixing any of their older products. Have a look here. Hope this helps. Link to comment Share on other sites More sharing options...
Discostu73 Posted October 20, 2018 Author Share Posted October 20, 2018 Thanks, I have contacted Snowy at pulsar who was going to phone me after a few emails back and forth. I haven’t heard from him as yet. You are quite right in that there is a huge amount of legacy pulsar gear still in use every day. Mostly in my experience the stuff is pretty bomb proof. That is why I am perusing the repair of this datapak, I am sure I will get there one day! I am posting here to get other views and advice while also sharing the outcome whatever it will be! Link to comment Share on other sites More sharing options...
indyld Posted October 20, 2018 Share Posted October 20, 2018 I wouldn't be shocked to learn that there is already an answer from Pulsar in this thread. :-) Link to comment Share on other sites More sharing options...
Discostu73 Posted October 22, 2018 Author Share Posted October 22, 2018 So I have now gone back to the beginning and I am checking control voltages present. The first time I tested this voltage I did so from the ends of either secondary coil together and got 35v or so. I removed the transformer (no mean feat) and checked that the voltage printed was 17.5 volts per side. I have since thought the control voltage was ok and have looked elsewhere for faults. Now retesting the voltage to the centre tap I have 17.5v one side and only 1v the other. I am testing these voltages as AC as I can’t see any signs of a rectifier. Have I accurately tested either side of the secondary AC using this method? And if this is accurate could this be the source of my problem and I need to get a new transformer? Link to comment Share on other sites More sharing options...
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