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Replacing a GX9.5 lamp (eg T29)


howartp

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Posted

Hi

 

We have a dozen Aria F1000's which take T29 lamps.

 

This sounds a ridiculous question, but is there something clever I'm missing about how to remove the old lamps from the GX9.5 base?

 

No amount of pure tugging releases them so I end up shoving a screwdriver down one edge (where the springs are) then hoping I can lever/wiggle the lamp towards me enough to free the spring at the other side. A 30 second job becomes a 5 minute job with lots of under-my-breath expletives. (I'm in a school so gotta be careful!)

 

We're going through lamps in SOME of these fixtures probably annually, yet the other half of the same lights - often lit in parallel - haven't been changed in 5 years, so I'm presuming something I'm doing is affecting how well they're seated or damaging something inside.

 

Before anyone asks, yes I'm careful not to touch the glass with my fingers as I'm putting the new one in; getting the old one out it's impossible not to!

 

Help??

 

Peter

 

 

 

Posted

Arias burn out lampholders for a living. I swear it's the 'Gillette' business model as I am always replacing the darn things.

 

The lamp is probably welded in place.

 

The best place to lever is either end where the ceramic meets the base. The springs aren't holding the ceramic that tightly, it's the pins are usually stuck. Long term, the holders end up needed replacing when the the spring contacts are particularly blackened and stop working completely.

 

(This is assuming that someone hasn't just helpfully jammed the lamp in the wrong way round - which would take some force!)

Posted

Look at the pins on the lamps you've removed. Do they show any signs of arcing?

 

 

Not that I've noticed; the lamps typically come out black, blue and bruised all over but I've not noticed the pins looking bad...

 

(This is assuming that someone hasn't just helpfully jammed the lamp in the wrong way round - which would take some force!)

 

Now you've confused me / worried me - the lamps don't appear to have any "this way round" mechanism - they're just two identical pins in a symmetrical (non-oriented) base aren't they??

 

Arias burn out lampholders for a living. I swear it's the 'Gillette' business model as I am always replacing the darn things.

 

The lamp is probably welded in place.

 

The best place to lever is either end where the ceramic meets the base. The springs aren't holding the ceramic that tightly, it's the pins are usually stuck. Long term, the holders end up needed replacing when the the spring contacts are particularly blackened and stop working completely.

That kinda rings true; I've got three fixtures that now won't light (one lit when I put new lamp in, tested it, rigged it, moved onto the next one and it just extinguished before my eyes). The lamp still looks pristine in two of them so lampholder issues could be right!

Posted

Now you've confused me / worried me - the lamps don't appear to have any "this way round" mechanism - they're just two identical pins in a symmetrical (non-oriented) base aren't they??

The GX9.5 has different size pins. The GY9.5 has identical pins. I think this is the same for all GY / GX designations.

Posted

Pretty sure(ish) that all the Arias that I've come across have a big pin, little pin (cardboard box) base that may not be totally obvious in the ceramic of the lampholder but certainly is obvious if you squint down the holes to view the lamp terminals. I'll have another look next time I'm somewhere that stocks them, but when replacing the holders I've used the ones sent from Italy through the distributor (perhaps AC Lighting, I can't recall) so they would be the correct ones for the lantern. I'm not sure of the exact vintage of these particular Aria 1K Fresnels as they have been rather hammered in hire stock.

 

If you do squint down the lamp pin holes, one set of contacts is often quite black on the lanterns that don't light.

 

The crew of a company that I do repairs for stick Arias on the 'fixit shelf' on a seemingly weekly basis. The main issues, other than a straight up blown lamp (which they will usually fix on site) is either burnt out lampholder, graunched cable sheath or strain relief gland that has come loose and fallen out.

 

Getting the bl***y things open isn't a picnic when the top cover is rusted in place.

Posted
Not that I've noticed; the lamps typically come out black, blue and bruised all over but I've not noticed the pins looking bad...

 

If the lamps are coming out in that condition I would have a guess you may have touched the glass.

You should only hold the lamp from its ceramic base when handling. If you do touch the glass, pop along to the science department and ask for a fiber free rag and Isopropyl Alcohol and gently clean the glass of the lamp before you switch it on.

Posted

I'm gonna have to have a look at them tomorrow - I've never found/noticed a right-way round problem!

 

I'm always careful not to touch the lamps other than by holding with paper towels from kitchen/toilet dispenser; until recently the focus-slider has been glued shut as the washers melted to the metalwork - thus I had no room to get my hands in to insert the lamps using only the ceramic. Certainly since I un-molded all the plastic I have been sliding them out the way to give far more access and thus haven't needed paper towels.

 

I'm hoping once this is sorted, I can lamp-swap on the bar (Scissor Lift) rather than derigging!

 

Thanks for all your responses!

 

 

Posted
Once a halogen lamp becomes a short life item change the holder. The holder is usually scorched and this burns the pin on the lamp, leading to ever shorter lamp life, getting worse as the holder burns more! Sometimes the contact spring just fades as they get too hot, swap them out and clean the vents.
Posted

The GX9.5 has different size pins. The GY9.5 has identical pins. I think this is the same for all GY / GX designations.

You have these back to front. The GX9.5 lamps such as the T11/T19/T29 have same sized pins, whereas the GY9.5 such as T26/T27 have different sizes.

Posted

Pretty sure(ish) that all the Arias that I've come across have a big pin, little pin...

 

I may actually be remembering this incorrectly as I can't easily find 1k or 1.2k GY base lamps on our supplier's site.

 

The plastic focus washer does have a tendency to melt which not only sticks the focus adjustment but makes it harder to remove the whole carrier for inspection. It usually just needs a good pull up after undoing the focus knob a lot. Removing the carrier completely is also a good way to get access to prise a welded lamp from the base.

 

Replacing the lampholder isn't a difficult task for the mildly competent. Biggest risk is trapping the wires underneath the holder when screwing it back into place. This can cut the cable with the resulting 'bang' when re energised.

Posted

The GX9.5 has different size pins. The GY9.5 has identical pins. I think this is the same for all GY / GX designations.

You have these back to front. The GX9.5 lamps such as the T11/T19/T29 have same sized pins, whereas the GY9.5 such as T26/T27 have different sizes.

 

Thank you. Indeed I have - easy way to remember - X is a more symmetrical letter than Y

Dave

 

 

Posted

To add to the points already made, If existing lamps are a challenge to remove, do remember to wear eye protection when attempting removal, if the glass or the ceramic base shatters a fragment in the eye could have serious consequences.

 

Gloves would be prudent also but eye protection is more important, hands heal from minor cuts caused by glass, eyes don't.

 

I agree that if in doubt about the condition of lamp holders, that they should be replaced.

 

 

 

Posted

Random thought: Could it be on some of the lanterns that someone has, in the past, replaced the lampholders with the wrong type?

 

To add to the points already made, If existing lamps are a challenge to remove, do remember to wear eye protection when attempting removal, if the glass or the ceramic base shatters a fragment in the eye could have serious consequences.

 

Gloves would be prudent also but eye protection is more important, hands heal from minor cuts caused by glass, eyes don't.

 

I agree that if in doubt about the condition of lamp holders, that they should be replaced.

 

BTDTGTTS - base shattered after it had jammed leaving a loose envelope and load of sharp porcelain bits.

 

 

 

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