AT least it’s noted that you don’t always have to replace the
socket - this assuming you even get that far in often those replacing the lamps don’t even think about it to that extent in putting perfectly good lamps into bad sockets and wondering why a few hundred hours later they are again replacing the lamp? Gee’ why did the lamp go bad? Simple question with any lamp all skilled tech people should be able to answer.
On the P-28s
socket (Medium
pre-focus for those that are not up with
current tech,) yea... I am probably at about 90% saved sockets at this
point over hundreds of fixtures with this
socket worked on. That said if weak spring - variable in that concept in how much tension verses how clean that center plate is for the lamp installed on it.
Some lamps have a large contact plate, others have a more or less ball of contact that requires a small surface area to conduct and these would require more tension on the spring to get a good contact.
One lamp better than the other? Sure the larger surface area if older
fixture perhaps but often they have solder blobs in not really a plate of contact in negating the
point. On the other
hand, if your
socket is pitted even after cleaning, such a ball of contact in perhaps contacting part of that while clean pitted part won’t have the surface area perhaps and the spring will otherwise be necessary.
Not actively comparing brands of lamp in who makes what style, but perhaps if older
fixture for a
Fresnel lamp, something that doesn’t have a center contact ball for contact instead of a plate would not be the best for use assuming warn out springs.
Stuff I don’t know: like if the ball of contact on above lamps extends a
bit further in compressing the spring a
bit more thus negating the question of one style or another. At some
point if really weak spring, wider surface contact or ball contact won’t help in resistance to
current flow.
Beyond that, some
socket center plates can be tightened some - and as you should check all of the various screws on a
socket during maintenance as they can loosen and resist
current flow also.
Side note, I store up parts in replacing broken porcelains with good gizzards
etc. Clean the attachment sockets also and if just
wire under screw in the connection... not good enough. Also padding under the
socket if
asbestos needs to be replaced. Lots of details in addition to just cleaning the thing.
If one is not able to really really inspect or clean a
socket, it’s probably cheaper in overall lamp life to just replace them. Would simply love if them with say a VL3K
fixture, if they would inspect the lamp to the extent of asking themselves why they failed? Say outer pinch failure due to bad lamp
socket... perhaps replace the lamp
socket while also replacing the lamp. This as opposed to throwing a perfectly good lamp into a perfectly bad
socket - some time six or more times again until the wiring to it melts down or the
socket cannot mount a new lamp. Lots of fixtures I see this general concept on. Gee... bad lamp, why did it go bad?
Same thing from
Fresnel to modern light often. Just a question of asking oneself while removing the old lamp, why did it fail?
On the P-28s, yea, I do stuff to them not recommended given like 20 years or working with them. Above concepts are correct and especially if not able to clean it. Than after that, the question of how much tension the center
socket should have. I think it nees as much as new - older spring tension mostly fine but debatable as with the lamp used in it.
This noting that the tension on a spring doesn't persay get more as you compress it, more that in the above if a little loose it might be less than proper tension to start if able to tighten.
Many lamp sockets out there
thru the years and some don't even fit in a
fixture the same as older ones do. Things you can do to them depend on the brand or style of
socket. Many can be saved and be fine, others need lots of work or cannot be saved.
Spring loosing it's tension either is from being loose that pounding a flange or tightening might solve or bad spring due to heat having tempered it in holding it's form instead of being a spring. Easy enough to detect. Springs don't persay loose their tension and perhaps it is even loose seeming in compressing, sufficient often for that central contact.
General concept in why one doesn't always have to replace a re-surfaced
socket, but on the other
hand might be safer if in doubt in doing so if not able to determine this.
