# Anybody change a Maxabeam's lamp?



## tvodrd (Dec 23, 2006)

I was playin' with the overdrive out in the desert on Thanksgiving and the lamp exploded- audible "pop" accompanied by instant darkness.  I hadn't gotten around to calling Peak Beam when Short Arc emailed me with what was supposed to be a very good deal on a lamp replacement kit. I bought it for ~$245.

Today I proceeded to install it. Loong needle nose pliers extracted the lamp's base from its socket behind the reflector, cleaned reflector with supplied solution/cloth after a major compressed air blowout. (I opened it out in the desert to dump the broken glass so it wouldn't be rattleing around inside the reflector on the ride home.) The reflector took some shrapnel damage which I hereby describe as "character marks!" 

Anyway, I put the supplied, safety glasses on and removed the cap on the lamp's clear plastic packaging tube. I grasped it by the front metal piece and pulled it out, at which point, the lamp dropped off the metal piece I was holding and hit the floor between my feet!  At least no "pop/bang" and need to tweezer glass from my whatevers. I just abt s...nevermind.

I pushed the lamp into its rear socket and clipped the front connection on, installed the replacement O-ring and stopped to think. Did I lose a spring, or was one missing (I couldn't find one anywhere on the floor) between the "shock absorber" piece that remained in my hand when the lamp dropped off of it or??? It seems to me there should be a spring in the front end of the lamp assembly. For giggles, I put the window back on and with the "centering adjuster" covering screws removed, took it to the garage and lit it off. The focusing motor couldn't and sounded to be in pain. It's like I didn't insert the rear of the lamp deeply enough into its socket. I removed the window and attempted to press it in deeper with no joy!

Anybody been there/done that and can offer some insights?

Larry


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## Ra (Dec 24, 2006)

Hi Larry,,

Maybe I can help you when you post some pictures..
Because reading your post, I cannot get a clear picture of what went wrong.

I've changed several MB-lamps, without any problems. The only thing you must be ware off is that the lamp doesn't get any stress sideways..

So,, I hope you can post some pictures.. Pictures of the new lamp are helping as well..


Edit: Oh, I forgot: There indeed must be a spring in the front-end of the lampmount: To (gently..) push back the lamp when focussing !!



regards,

Ra.


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## Ra (Dec 24, 2006)

Larry,

I made a quick drawing of the front lamp-support of MB..

Hope this helps..:







I didn't draw the + connecting wire...


Regards,

Ra.


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## tvodrd (Dec 24, 2006)

:bow: Ra!!! You just made my "list!" (That's a good thing.  ) I know I saved the metal part of the lamp when I dumped the glass out in the desert, but damned if I can find it. The replacement lamp kit was from ebay and was either missing the spring or it flew when the rest of the lamp hit the floor. Your sketch makes perfect sense, and thanks! I have enough brains to install a "gentle" spring to replace it.

Larry


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## Ra (Dec 25, 2006)

Thanks Larry,

I don't know about your level of "Maxabeam-knowledge".. But if things start to work, you propably have a bit more of lamp- and focus-adjusting to do ..

Do you know about the programmable spot- and flood-focussettings??: They need to be set if you want the MB to stop exactly at the tightest spot or the max flood you think is usable.

And you propably need to re-adjust the X and Y-position of the new lamp: No lamp has its arc at the exact same spot, and with an arc that small, de-collimation as a cause of slightly different lamp-dimensions (within 1mm..) easily occur !

Ofcource if you are in the posession of the MB-manual, you propably know all these things and don't need my help...

A tip: The best place for (temporarely) saving very little, but important parts: YOUR WALLET !! ... Works for me !!

And another thing: Be gentle on using high power mode: The electronics overdrive the lamp, which must cope with extreme pressure and temperatures even at nominal power !! 
A short-arc lamp has definitely not the "safe overdrive range" you find with Luxeon or Cree emitters !!!


Regards,

Ra.


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## ShortArc (Dec 25, 2006)

Larry,
I should be receiving my replacement lamb kit tomorrow. I will check what was included. 
Also these are Gen 2 bulbs but are supposed to work with any Maxa Beam.
Willem.


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## ShortArc (Dec 26, 2006)

Larry,
I just received the replacement kit. 
The “shock absorber”, as the replacement instructions term it, is part of the lamp assembly and comes with the kit! Just as RA drew it! Worst case I can send you mine (as I don’t need it yet…tempting Murphy here) and you can machine one up at your leisure.
Willem.


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## tvodrd (Dec 26, 2006)

Hi Willem,

Either my replacement lamp was missing the spring or more likely, I lost it when the lamp hit the floor. I am missing only the spring, and am sure I can find a suitably low-rate replacement in my collection. I'm going to disassemble it further to figure out what's wrong with the focusing. Broken glass in the mechanism?

Larry


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## ShortArc (Dec 26, 2006)

Here is a pic of the bulb with the “shock absorber” pulled appart.


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## Ra (Dec 26, 2006)

Hi ShortArc,

I noticed something in the picture of your MB-lamp..

Look at this picture of my lamp.. See the difference ??:







A few years ago someone in holland came to me with a Maxabeam, he wanted the tightest focus possible, but was not satisfied with the way MB performed on that field! After days of testing I found the problem: The shape of the bulb !! His MB had a tube-like bulb like the one on your post (so not globular..).

The problem that occurs with tube-like bulbs is called optical arc-image dissplacement. With an arc that small it is very important to have a globular (round..) bulb. Otherwise you will lose a lot of cp's at spot-focus: Difference can be up to 2,000,000 cp !!

I also doubt the bulb on your picture is an original MB-replacement bulb, because I think the engineers at Peak Beam know of this problem.. But I can be wrong: The bulb in the case mentioned above also was said to be an original MB-bulb..


Regards,

Ra.


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## ShortArc (Dec 26, 2006)

Hi Ra,
The bulb I am showing is an older design (late 90’s I think) but it is the original Maxabeam bulb of the period You are depicting the new design which is also currently in my Gen 3 Maxabeam. I am not aware of any performance issues with the older design but that would be a good question for Bob Kleinhans at Peakbeam. 
Willem.


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## Ra (Dec 26, 2006)

Everyboby is celebrating X-mas, and we still are talking lamp here.....That really makes us FLASHAHOLICS !!!


To be a little more clear about arc-image dissplacement I made a simple drawing:






With for example automotive HID, arc-image dissplacement is not an issue because of the much bigger size of the arc..

But the high quality parabolic Maxabeam-reflector concentrates on the hotspot in the 0.7-0.9mm arc, which is only about 0.1mm!.. Making this optical dissplacement a very big issue !!

Regards,

Ra.


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## ShortArc (Dec 26, 2006)

Ra,
Very interesting! What kind of manufacturing tolerances are imposed on these bulbs?


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## Ra (Dec 26, 2006)

Like I said earlier, the dimensions of the bulbs may vary within 1 mm or even more. (total length, electrode-arcgap distance) Ofcource the more important dimensions like the arcgap itself and electrode-diameters (lamp-base) are within 0.1 mm or less.

But the collimating possibillities on the lampmount of Maxabeam an cope with much more than that..

Oh.. Forgot to mention: Did you see my little 10watt HID-monster.. There I killed the optical dissplacement by removing the protective bulb from the 10watt Solarc lamp. To be able to concentrate on the little hotspot in the arc near the anode: Generating 250,000cp in the center of the beam.:






Beampattern:







Regards,

Ra.


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## Ra (Dec 26, 2006)

And here is a little tip: That is,, if you have some machining skills

Earlier, I made this mount:






To fit general 75watt Xenon lamps in Maxabeam.. The best lamp to be used with this mount is the Ushio UXL-75XE:






Keeping my eyes on Ebay, I've now 6 of those lamps to use in MB and to experiment with. 
It is a much cheaper solution for Maxabeam: I got those lamps for $30 each !!

Not on the pictures is an adaptor cap on the - electrode of the lamp, you need that to increase the diameter of the -electrode-base from 7.5mm to 9mm !

Regards,

Ra.


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## ShortArc (Dec 27, 2006)

Ra,
Extremely informative. Great tip on the Ushio UXL-75XE!!!


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## tvodrd (Jan 15, 2007)

Back on topic, I met Robert Kleinhans(sp) at the Orlando SHOT Show. I have spoken with him a couple times before re a Maxabeam group buy and an AN/VSS-1 tank searchlight. :green: (I got to meet the fellow engineer!) It turns out that later Maxabeams have a lamp assembly that is longer. To install one in an early rev one has to shorten the telescopic, spring-loaded front piece of the lamp assembly. I bought mine as part of a CPF Group buy and they were "prime" NiCad units! I'd maybe add a link, but it's 02:30 CA time, and I spent the last 3 nights in Orlando! ;D

Larry


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## ShortArc (Jan 15, 2007)

Interesting…thanks for the info Larry.


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