Lizfowler Posted October 28, 2011 Share Posted October 28, 2011 Hi, I have two 500w Fresnels, as well as others, rigged up in my studio. When I bring them up on the board they seem to take ages to warm up! When I bring them up they are very dim and if on full, after about 10 minutes they start flickering and then they jump up to their brightest every time. Every other lantern on the rig seems absolutely fine. The only problem is the two fresnels. They are patched in to the same channel, I have tried patching them into another channel and they do the same thing! Has anyone experienced this before? And if so are there any solutions to this problem or does anyone have any advice to give me? Thanks Muchly Link to comment Share on other sites More sharing options...
willdoweuk Posted October 28, 2011 Share Posted October 28, 2011 This sort of thing happened to me in school once. Turned out someone had just put in an incorrect lamp (bulb). Link to comment Share on other sites More sharing options...
peza2010 Posted October 28, 2011 Share Posted October 28, 2011 Do you pre heat your rig at all? Link to comment Share on other sites More sharing options...
Lizfowler Posted October 28, 2011 Author Share Posted October 28, 2011 I do preheat the rig at about 15% for a couple of minutes, but it is not until I have put the Fresnels on full for a good 10 minutes that they start working properly! I suppose I could check the lamps - I haven't changed them so they could be wrong. And that would make sense as the other 500w fresnels work absolutely fine! Link to comment Share on other sites More sharing options...
Shez Posted October 28, 2011 Share Posted October 28, 2011 If they're taking 10 minutes to sort themselves out, pre-heating won't make a jot of difference. I'd certainly be looking at what lamps are in them as a first port of call. Try plugging them in to a 13A socket (via an adapter) just to remove the dimmers from the equation completely. It almost sounds like someone has managed to put some sort of energy saving lamp in there :blink: Check the wiring too, both in the plug and inside the lantern for loose connections. (Greetings from QE by the way) Link to comment Share on other sites More sharing options...
ramdram Posted October 28, 2011 Share Posted October 28, 2011 Presuming I have understood the problem...If you done the substitution thing with the channels, and either used another grelco (?) or different xleads, AND, checked the connections in the plugs, AND the heat resistant wiring in the lantern, then you could reasonably expect the lamps, in the fresnels, are either "duff" or the connection ie, lamp pins into the lantern sockets are "duff". Were you to remove the original lamps and examine the pins you may find they are scorched. Do not forget to handle the glass envelopes with either a tissue of hankie say so you do not leave fingerprint grease on the glass. (IF you do have to replace the lamps make sure you follow the instructions to the letter.) If this is the case then it may be the socket on the lantern is damaged too. Did you hear any crackling noises or smell any hot metal when the lanterns are heating up? Suggest you try a new lamp and go from there. If new lamps do not appear to resolve the issue then it may be the lamp sockets are duff. The sockets can be replaced, assuming of course you can source the replacements or the repair place can. HTH Link to comment Share on other sites More sharing options...
Neil Hampson Posted October 28, 2011 Share Posted October 28, 2011 Considering the extent of the problem described, if it is corroded / arc damaged pins, I would expect the lamp holder to be replaced anyway. The contact on the lamp is quite thick, about a 4mm pin, where as the contact on the lamp holder is generally just a very thin strip of spring steel, the lamp holder would probably burn out first. When you get the lantern down, check the wiring very carefully as well as there could be a lot of heat damage. Link to comment Share on other sites More sharing options...
Modge Posted October 28, 2011 Share Posted October 28, 2011 Has someone managed to put an odd dimmer curve on that channel, either at the desk or the dimmer?Shez's test will rule that out for you. Link to comment Share on other sites More sharing options...
paulears Posted October 28, 2011 Share Posted October 28, 2011 If we're taking bets, I wonder if the wrong lamps are fitted, so one of the terminals is just touching - it could be arcing and heating up, and most of the symptoms described fit? Link to comment Share on other sites More sharing options...
ocfe Posted October 28, 2011 Share Posted October 28, 2011 Hi, I have two 500w Fresnels, as well as others, rigged up in my studio. When I bring them up on the board they seem to take ages to warm up! When I bring them up they are very dim and if on full, after about 10 minutes they start flickering and then they jump up to their brightest every time. Every other lantern on the rig seems absolutely fine. The only problem is the two fresnels. They are patched in to the same channel, I have tried patching them into another channel and they do the same thing! Are they fitted with a discharge lamp and gear? Link to comment Share on other sites More sharing options...
DonkiDonki Posted October 28, 2011 Share Posted October 28, 2011 Have you tried swapping the slow fixtures over with some of the good ones which will tell you if the problem lies with the fixtures or the sockets? Also compare the fixture and lamp type while your at it, any differences may highlight the cause. Some possible causes? Most of the fixtures are running tungsten whilst the two slow ones are something like HID? Loose connection somewhere in the power supply to the sockets; sits there arcing until its warmed up and semi welded in place? (Hope it's not that one)Have you tried turning them on directly from the dimmers? Could be a programmed fade time or custom dimmer curve on your desk? Link to comment Share on other sites More sharing options...
dmxtothemax Posted October 29, 2011 Share Posted October 29, 2011 To start with you must findf out if the problem is in the light itself, or in the control gear ( dimmers ). So bypass the dimmers completely and plug the fresnels into a close by power point ! I f they come on correctily, then this says the dimmers are at fault !If they still play up, then the problem lies in the light itself ! But if two lights are doing the same thing, then I am inclined to lean towards dimmer problems, possibily even a faulty patch lead. Link to comment Share on other sites More sharing options...
Nicktaylor Posted October 29, 2011 Share Posted October 29, 2011 If we're taking bets, I wonder if the wrong lamps are fitted, so one of the terminals is just touching - it could be arcing and heating up, and most of the symptoms described fit?And of course the minuette lamp has not got simmetrical pins so someone could have forced in the lamp the wrong round and ths smaller pin is now arcing. As another posted almost certainly will require a new holder Minuettes very susceptible to this problem Link to comment Share on other sites More sharing options...
ramdram Posted October 29, 2011 Share Posted October 29, 2011 Ref the duff lamp suggestion Liz, have you in fact recently replaced said lamps? The fact that two lanterns are affected at the same time, hence your post, suggests you may have bought and replaced two lamps sourced at the same time (and from a single supplier). It might have been a notion, if you had recently replaced them, to mention this in your post, ** laughs out loud **. Presume you will now have very carefully checked to see that the lamps are in fact designed for the lantern AND inserted correctly? It may be that you will now need to have the fresnels serviced with a view to replacing any duff sockets. A lesson to us all..always replace like for like and double check the polarisation aspect. Link to comment Share on other sites More sharing options...
boatman Posted October 29, 2011 Share Posted October 29, 2011 The pins on a T18/T25 are different diameters. I had a similar fault on a Quartet several years ago and the lamp had been inserted the wrong way round. If sufficient force is applied the thick pin can be made to fit in the socket hole designed for the thin pin. It makes good contact but the thin pin in the hole designed for the thick pin doesn't and there's arcing until the pin heats up and expands. If this is the cause, you will probably have to replace the socket as it will be distorted. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.