Graphite is conductive so if you attempt to use it, be very careful about any of it which either as a liquid spray runs out of the
socket, or as a powder... not sure what good the powder form would do since it would follow gravity and not apply itself to the walls of the
socket. On Lighting
Network there was a decent discussion about lamp bases to Sports Lighter fixtures and what chemicals and coatings work well on high temperature lamp bases. While I have high temperature spray on Graphite, I find it more useful for coating the insides of old
Altman 360Q lens trains in making them move well. I am not sure I would trust graphite inside of my lamp
base.
If a
terminal shows arcing, the lamp
base will also. Those little arcs prevent good contact with the lamp in forming a high resistance
conductor. This resistance adds heat which in turn further melts down the lamp
base and lamp's pins. Flipping the lamp over and putting a good pin into a bad
socket will as you are doing work for a while in providing at least a cleaner surface area for contact. In this case, the bad part of the lamp
base will just start melting
thru the fresh pin at the same time as the bad pin than starts to melt
thru the good part of the lamp
base.
While you can clean the badness of the pins to some degree with a fine
emery cloth as long as you than remove the scratches from the surfact with some chrocus cloth which is even finer in grit and don't try to remove anything but what is sticking up above the normal surface. Don't try to remove pock marks and pits because the pin than will be out of round and the larger amount of surface necessary to be removed to get rid of the holes will no longer be in contact with the lamp
base. This than will force even more
current and thus heat on other parts of the lamp
base and pin which still do have a fair amount of contact. Also if your pin gets too small, it won't have good contact with the lamp
base which will also cause arcing. I'm not sure how much effort this cleaning of pins will be worth due to the size of the pin and expense of the lamp. There is a nickel plating on the pin which helps prevent oxidation and heat damage to it. Once you sand that coating off or scratch it sufficiently, it will no longer provide a good contact either and probably corrode anyway which will start the problem all over again. There are coatings you can add to re-protect the pin, but to some extent such lamps due to the size of the pin are not worth the effort. A corrode and melted pin is useless,
throw the lamp out before it goes into another
fixture and destroys it's lamp
base. Additional problems with bad contacts would be first heat on the lamp
base which could destroy the
pinch seal of the lamp in causing it to go bad faster, and the extra heat making the
wire feeding the lamp
base melt down where it hits the lamp
base.
This is also true with the lamp bases. If just oxidation or a
bit of charring, the contact might be able to be cleaned with a thinned out cotton swab so it fits into the hole with perhaps some peroxide or electrical contact cleaner applied to it, but the dia. of the pin hole is for the most part too small for much more than that amount of effort. If the lamp
base at that
point does not become clean, it's time to replace it. There are other tools you can use to clean the
base but this should be the simplest in either working or not working. You cannot re-surfact the lamp contact, too small to be working inside of and too small a metal plate you are attempting to work on. By the time you cleaned the surface, the contact's metal would be too thin to resist the heat and
current running
thru it very long. I do frequently re-surface both lamps and lamp bases of all types but even I don't touch this type of lamp
base - too small to work with and not worth the effort.
Fresh lamp bases are very necessary for these fixtures and 10 years is a decent amount of life they have had. Specifically on lamp bases the
Altman #97-1580, a high temperature TP-22
base rated for 1,000w/250c in temperature sells for about $16.00 each from sources anywhere from
Production Advantage to
Altman themselves. Make sure your product has this part number no matter what source it's from because there is three other types of lamp
base on the market
Altman either sells or used to sell which will be a lot less effective in your
fixture.
While
Altman recognizes many other brands of lamp
base you can get
thru other souces - such as those frum Sylvania,
Altman, Bender and Wirth, they do not at this
point recognize the Ushio C3A lamp
base which is often sold as a replacement lamp
base for this
fixture at a lower cost. The C3A is very popular amongst retailers because depending upon their discount factor with Ushio, the lamp
base can be cheaper for them to
purchase and in testing by respected users it preforms just as well. However as stated by a engineer at
Altman about this lamp
base, use of the C3A until such a time as
Altman approves it will void the UL listing on this lighting
fixture because both
Altman does not recognize it in having tested it and the lamp
base is itself not
UL listed.
The extra $1.35 per lamp
base normally the difference between the
Altman and Ushio lamp bases is worth the extra cost. At one
point I might also have taken apart lamp bases in combining two half good ones into one with good contacts. This was a long time ago and will have by doing so also voided the UL listing on the lamp
base. The
ETC fixtures are good in that they like an old
PAR can's lamp
base are designed to come completely apart. Unfortunately however as opposed to the cost for an entire TP-22 lamp
base, just the contacts alone from
ETC cost that much. The entire lamp
base assembly would be more expensive.
One further thing to check is the
fixture's
plug. Make sure ferrules were used if a
stage pin type and that the screws no matter which brand are tight.
I recommend on a
stage pin plug that in addition to the 12ga ferrules that you
purchase from a electronics supply or McMaster Carr some insulated 16ga ferrules for use with the 12ga ferrules inside the
plug. Given the over twice the dia. of a 12ga
ferrule on a 16 ga.
wire, there is only marginal protection given to the wires above the screw clamping directly onto the strands. Often the 12ga
ferrule given the lack of wires will just cut right
thru the 12ga
ferrule anyway than cut into the conductors anyway. In any case, the screw onto the wires with this size of
ferrule will not sufficiently enclose all the wires to the extent that the pressure of the screw will clamp down on all of them to the same amount. Some strands of the wires will have more clamping than others thus a bad connection.
You can fold the
wire over on itself by stripping twice the length and folding it back on itself but frequently with heat
wire you won't be able to get the fold tight enough.
You can also strip the
wire twice as long, than half way up strip the
wire again for a 18ga
wire in cutting strands, than fold the top part of the
wire back on itself. This than often when folded has sufficient amounts of
wire to fit with the fold into the 12ga
ferrule.
In both cases, it's a question of folding the
wire back on itself to act as a filler sufficient in filling up the larger
ferrule with
wire so that it's full of
wire and does not just crush into the conductors.
The easier way to do it as above is with a insulated 16ga
ferrule which has a
PVC flare out coming off the metal part protecting the area close to where the
wire is stripped from shorting to anything. The
ferrule itself is proper for the
wire but too small to reliably fit into the hole of the
plug. Adding the 12ga
ferrule as a sleeve over the 16ga
ferrule than sleeves the 16ga one sufficient to both fit into the
terminal and with the second layer of metal covering the
wire, there is little chance that the screw
terminal will cut
thru one
ferrule and than cut into individual strands of the
lamp cord.
As always, give a tug to your wires once they are in the
terminal to ensure sufficient pressure was put on them. 1/4 turn past finger tight might be an illusion if there was a ding in the screw's threads
etc. in being tight in the screw but not tight in the
terminal.