lamp/socket comments

[galighting]

I have a client that states from time to time he has to "tap" on two of the pathlights that I installed in order for them to illuminate. He say's that after a few days he will have to "tap" on them again and they will be fine. I'm curious if the problem is in the halogen lamp itself or the fixtures socket. I am using a well known fixture so I am assuming that he might just have some bad lamps-which I have replaced once already.

Any help?

[sitelights]

Intermittent contact is the villain here since tapping the fixture minutely changes the relationship between the corroded lamp base and the corroded socket and re-establishes however briefly the contact point. Welome to the club.

Take a look at other posts in the "lamps (light bulbs) and sockets" forum titled "indoor/outdoor lamps", "average lamp life & bad lamp sockets" and "bulb/socket types".

The search function may also be of some help; key in relevant search terms to find other posts on the topic.

Unfortunately the archive goes back no further than April 2005 but if you search manually you will find many, many references to the problem in a variety of contexts.

Over many years I have been of the opinion that most lamp failures are actually socket failures.

There is no easy fix for this problem (it is a manufacturer's defect but they are loath to admit it) but cleaning the lamp pins or the socket jaws with a very fine file or a sliver of emery paper with buy another few months of operation.

Wedge base lamps use loops of wire as contact points and since the looped wire has more bearing surface it is marginally less likely to fail due to corrosion.

Every professional using this site has an opinion in this matter and I hope you get other responses. Gold plating the sockets and the lamp pins would eliminate the corrosion problem but that is not likely to occur. One could, however, individually electroplate the pins and sockets and thus correct the manufacturing defects we all have to live with.

[JC Lighting]

There is another problem I have experienced that results in a temporary fix by "tapping". Numerous times I have gone up to a fixture with the lamp not on but voltage was present and the lamp came on when I was attempting to take the fixture apart to test the lamp for continuity. The first few times I thought it was corrosion on the socket/pins. As I continued to experience this situation I began to be more purposeful when handling the fixture and lamp. Over time I discovered that I could slowly move the lamp in the socket and it would not come on. When I performed a continuity check the lamp was open. Then I could place the same lamp back into the socket ( still not come on ) and "tap" the lamp sharply and it would come on. Sometimes the lamp would show an instant glow but go out. With a second or third tap it would stay on for the night but be out again the next day. I discussed this issue with others and have concluded that the filament is arc welding itself back together for a short period and then burning out again in an hour or so.

Jim C.

[sitelights]

I moved the three posts from the "control systems" forum to the "lamps..." forum where they will be easier to find for anyone specificly looking for info on this topic.

Since all professional designer/installers relamp "hot" (don't try this at home kiddies) we have all experienced a dead lamp coming to life when moved; this can result in a painful burn.

There are other posts on this topic in addition to those previously listed; these are in the "lamps..." forum: "lamp testing" and "testing pin type bulbs" and the response to that post. There are numerous other relevant posts scattered about the site that mention this problem in passing while addressing another topic.