Quote:
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.' "
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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.