Corroding S4 bases

[CynicWhisper]

Hey everyone, just curious if anyone has any solutions to this problem that has seemed to plague my theatre. Our Source Four ellipsoidal bases are constantly corroding/oxidizing and we've tried a thousand and a half ways to fix them. The only solution we've found that works is replacing the contacts, but unfortunately, this gets expensive fast. We've also just brushed out the contacts with wire brushes, but they only work briefly before going back to the original problem. We aren't sure why they keep dying, but it's killing our inventory.

Anyone else had this problem? Or a solution?

[SerraAva]

You can use a dremel on the bases to clean the contacts. They will still eventually wear out, but it's a quick, easy way to clean them.

[derekleffew]

Do you keep buying the same brand of lamps over and over? Have you contacted ETC about the problem? It just so happens we have a lamp expert here on CB, and he'll be along shortly, so I'll defer to him.

[icewolf08]

Here is another question, do you change the lamp base and then put the same lamp back in? Once the pins on a lamp start to oxidize they will continue to even in a new lamp base. Why? Because the oxidation and carbon deposits and any other gak that gets in there resists the flow of electricity. More resistance begets more heat, and more heat begets more destruction of the lamp base and pins.

So, even if the lamp is good it will still cause bad things to happen if you continue to use it. You can clean the contacts, but you have to be carful because if you scrape or grind and you change the shape of the contact you can cause arching when it doesn't seat properly in the lamp base. Also the oxidation/corrosion can cause the shape of the pins to change thus causing more arcing. Yet one more reason to to keep using the old lamp even if you clean it.

[derekleffew]

I should have remembered that, Alex. In the 80s I had a Strand-Century dealer tell me, "it's like VD: lamp causes bad socket, then bad socket causes different bad lamp, then lamp causes different bad socket....the gift that keeps on giving, and before you know it, your entire inventory is 'infected.' "
This was about TP-22s and FELs, but the same applies. S/C replaced about 30 of my sockets for free (some which had come out of Kliegl fixtures...shhh!) They suggested NOT to use emery cloth or Dremel tool on the lamp pins, as that would make them smaller and thus cause more arc-ing.

I'm pretty sure ship has addressed this issue before, I just can't find it.

[Footer]

Originally Posted by icewolf08

Here is another question, do you change the lamp base and then put the same lamp back in? Once the pins on a lamp start to oxidize they will continue to even in a new lamp base. Why? Because the oxidation and carbon deposits and any other gak that gets in there resists the flow of electricity. More resistance begets more heat, and more heat begets more destruction of the lamp base and pins.
So, even if the lamp is good it will still cause bad things to happen if you continue to use it. You can clean the contacts, but you have to be carful because if you scrape or grind and you change the shape of the contact you can cause arching when it doesn't seat properly in the lamp base. Also the oxidation/corrosion can cause the shape of the pins to change thus causing more arcing. Yet one more reason to to keep using the old lamp even if you clean it.

Especially in older fixtures, I find that most physical notes tend to lend themselves to a bad base more often then a bad lamp.

Remember, these things have to pass 5-7 amps through them in extremly high heat situations. S4's don't have the best designed base cap, but at least swapping out the leads is quick to do and relativly cheap. I always find it interesting when people will spend 15 bux on a new lamp every time the base fries the contacts, but go nutz when people will run 6 lamps through without replacing the base.

[Charc]

Originally Posted by Footer4321

Especially in older fixtures, I find that most physical notes tend to lend themselves to a bad base more often then a bad lamp.
Remember, these things have to pass 5-7 amps through them in extremly high heat situations. S4's don't have the best designed base cap, but at least swapping out the leads is quick to do and relativly cheap. I always find it interesting when people will spend 15 bux on a new lamp every time the base fries the contacts, but go nutz when people will run 6 lamps through without replacing the base.

Older caps or newer caps?

[avkid]

How about contact cleaner?
http://store.caig.com/s.nl/sc.2/category.188/.f

[ship]

Originally Posted by derekleffew

"it's like VD: lamp causes bad socket, then bad socket causes different bad lamp, then lamp causes different bad socket....the gift that keeps on giving, and before you know it, your entire inventory is 'infected.' "

I love it and gonna steal it. For the most part, I have nothing to add to the above wealth of comments. Also a good point about people complaining about the price of replacing the lamp socket yet they don't mind going thru lamps left and right - or don't bother inspecting the used ones for this condition so as to prevent a problem.

Small sockets under and possibly including G-12 in size don't take to cleaning very well or Dremmeling. - Add to this the thinness of the contacts once if even possible to properly clean them and you get around 6.x amps running thru a very small thickness of no longer even gold coated metal making up the lamp base with very high heat in the area.

Contact cleaner also won't work as with deoxident in not working, not rated for the temperature and first you would have to remove what is wrong before you can coat the surface and or clean out any residue left. These things are not rust/oxidation reformers, and even if they were what the oxidation / welding / melting / corrosion has been reformed to does not conduct very well. Other types of deoxident such as copper imbeded also would not work in such a small area given you have to first clean the contacts, and the chance of applying too much and shorting to the frame or other contact.

There is reports of copper filled deoxident working well (not tried by me) in the case of larger lamp sockets that have been properly resurfaced but have some pitting so as to fill in the holes as it were but not where the socket has not been already resurfaced.

Consider surface contact when looking at bad lamps/sockets. Current does not travel thru carbon buildup / burned and melted areas easily or thru areas that lack physically touching the lamp base with a good connection such as in the case of pitting or a loose fitting lamp socket. The wattage of the lamp has not changed and that means the amperage is traveling thru what little area is in contact with the lamp. This amperage due to resistances in the metal and heat given off by the lamp than gets really hot and both expands the bad area if not welds lamp base to the lamp, and creates new areas of heat. This in addition to given high resistance of the lamp base while current if flowing a lot of heat is given off in exchange - hot enough to weld metal such as the lamp base contact to the pins of the lamp in some cases. (This granted the amperage of a HPL lamp is not all that high and the gold contacts don't weld well to the nickel plating of the HPL lamp as easily as with other lamp / socket types.) Gold' has a fairly low melting temperature also - don't believe ETC switched materials for this but it is probably very low amount of gold in the socket contact. (Forget if it was fully gold contacts or just coated gold contacts.)

ETC recently upgraded their lamp base sockets recently as I remember also so it might be better now. Believe it's an Osram socket that I could verify the material making up the contact given some time and if it's of interest. The upgraded lamp bases that are now an all in one part with porcelain and mica insulator is a good thing. Once had a tech person replace a bunch of lamp bases on some fixtures but she forgot to install the mica inculator behind the contacts. There was a bug hunt in finding the fixtures now shorting to the frame of the fixture and there was a lot of fixtures she changed the lamp bases on.

While the upgraded lamp base is probably superior in being longer lasting than the older version (don't know, don't run that department) and the all in one lamp bases now are safer given a potential safety hazzard if someone forgets the mica behind the contacts, I'm kind of dissappointed ETC did not just offer the sockets all by themselves without wiring attached. This at least for the old style part was just a crimp terminal where it attaches to the wire with a lamp base socket on the end of it. Will have been not more than like a buck or two per crimp as opposed to like twenty dollars for the wire/crimp assembly. This granted it necessitates the end user able to properly crimp the wire to the crimp terminal part of the socket, but for high end users such as myself that has that ability it should have been an option. This will have saved hundreds of dollars if not more over the years were we just able to do or own crimping. This much less often the heat wire feeding the lamp socket contacts was in perfectly fine shape and did not need replacement.

Still the S-4 light fixture is what it is now - what fifteen years old now. I hear thru the grape vine that new lamps for them are under way and perhaps new sockets will also be TBA. In the mean time, Osram does make the ETC lamp base assembly, any theater or lamp supplier that can get an Osram lamp might be able to get it cheaper direct than thru the ETC route.

[ship]

I don't physically deal much with HPL lamps in their demise other than collecting them up for a study at the moment (those that know who I am off line, send me your spent HPL lamps for the next month or three to help with this study - it could be really useful in advancing the lamp science and I might be able to swing some exchange). I do buy the lamp base replacement parts and save a good amount of money in getting them for a multitude of lamps thru my lamp distributer as opposed to direct from the fixture manufacturer. This is the case of the HPL and even Mac 2K lamp bases, but I buy such parts in bulk as a minder here in what saves me money does not at all times mean it will be cheaper on the onezees or even twentyzees amounts.

The following photos show examples however of some Mac 2K or Mac 700 lamps which also had bad lamp bases which caused lamp failure. Often those changing the lamps won't note the lamp socket or even condition of the lamp base on the lamp and they will just return the lamp as bad or "exploded" but won't consider on these $100.00 plus lamps each what caused that failure. AT times before I even get to inspecting and tracking the lamps on the computer, they will have already have had two or three lamp failures in the same lighting fixture due to a bad fixture lamp socket and still not have changed it. That means the price of lamps, plus man-hours at times in premium IA labor for the time to change the lamps each time all caused by a bad fixture lamp socket that is killing off lamps left and right. Do my best of course to warn the crew chiefs of the tours... pull VL3K SP 126 from service ASAP, it's on it's third lamp in six months now caused by the same bad lamp base, but often that is really hard to do in figuring out or remembering what fixture that was amongst a few hundred lights and won't be found until the next lamp fails thus costing upwards of well over $400+ per time it happens on each fixture before it has a hope of a problem solved. This given a lack of inspecting the lamp and understanding what caused the failure.

The following is some photos of bad lamp bases caused by bad fixture lamp bases. 034, note the lower one with it's darker color of lamp base and bent screw thread. 009 while not such a great photo shows a monofoil that escaped thru a pinch crack on the lamp. Question is what caused this failure, the bad fixture lamp base overheating the lamp or a fault in the lamp? Overheating of the fixture socket in this case caused overheating of the lamp and it's failure -another stage hand's day rate in one bad lamp means one less day someone is employeed - at least how I consider such things. Of the three lamps in photo 001, none show signs of overheating and all were lamp based failures.