Author Topic: Replacing a Nexxtech “Xenon” rubber flashlight (#6119014) light bulb (Philips HP  (Read 747 times)

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Offline FlashLightUser

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Some years ago, I picked up this tough looking flashlight at "The Source by Circuit City" in Canada:



I dropped it, and it no longer works.  I am assuming that the bulb is not working, even though there does not *appear* to be a break in the filament:



However, store no longer carries the bulb.  I contacted them through their online chat service to find this out.  Googling the bulb manufacturer and model doesn't yield anything.  It looks like I have to throw out the flashlight. What an environmental crime.  Can anyone suggest how to source down the appropriate bulb?  It doesn't seem like flashlight bulbs are standardized.

Offline robo819

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There are still a lot of places to find the Xenon bulbs. The one thing you do have to know is the voltage that the light makes.

These bulbs are rated for different voltages so getting one that is not high enough will assure it burns out right away and getting a bulb that is too high of voltage will result in a very dim light or it wont come on at all.

There are also some various bases on the bulbs , but I think the standard base used was mostly the P 13.5 S base for the everyday flashlights.

Offline FlashLightUser

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I didn't notice that the subject line got truncated, but it should have specified the bulb model info from the stem as Philips HPX42, 4.7V 0.4A.  It takes 3 AA batteries.  If you say that stems are somewhat standard, then I will look for a "P 13.5 S".  Some sites recommended elsewhere are bulb town dot com or top bulb dot com.  Thanks.

Offline robo819

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I think any of the bulbs that fit the older 3 cell Maglite should also fit the light you are asking about.
It should not matter if it list for AA , C , or D cell or whatever because they are all 1.5 volt batteries.
« Last Edit: June 08, 2018, 06:13:14 AM by robo819 »

Offline FlashLightUser

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I see what you say about the voltage.  I was equally concerned about not knowing how standardized the base is.  I thought that HPX42 was a Philips model number, so I searched for "HPX42 Philips" without quotes. I didn't notice anything relevant, but I must have missed a link. Here is a *very* helpful link: http://onninen.procus.fi/documents/original/13061/7/0/5021.pdf. Googling "HPX42 bulb" without quotes yields a table with nearly the same kind of info: http://www.candlepowerforums.com/vb/showthread.php?271713-PR-bulb-ratings&p=3814026&viewfull=1#post3814026. Both show HPX42 as 4.7V, base P13.5s. One has to be careful, as local hardware stores have identical looking bulbs that require approximately half the voltage (Krypton, I think). Having searched around locally, I think it might be wise to just search Amazon, as I probably burn up many times the cost of gas just to find a suitable bricks-and-mortar source.

As a fallback plan, the last place I visited suggested a local establishment, "Buchanan Lighting".

Based on the opinions of staff at the 1st last place I visited, I might be better off finding an LED with the same base and voltage. They are brighter and the batteries will last longer. Being an electrical engineer by training however, I was initially concerned that the right voltages might be hard to find. My flashlight serializes 4 AAA batteries, yielding 6V unloaded, and 4.8V loaded (the latter from a loaded voltage of 1.2V/cell, provided in another forum). I would need a LED bulb that accepts this kind of voltage source and loads it in a similar manner. I'm naive about batteries and flashlight bulbs, but if a bulb is designed for a 4-cell, then its loading effect should take into account the output resistance of the batteries, so the only important parameter is number of cells it was designed for. The exact loaded voltage will depend on the bulb design, and whether that yields the right operating voltage is the bulb designer's problem.

The take-away is that I only have to match the cell-count and the base specification. I then have the freedom to choose things like LED rather than xenon or krypton. I took the above candlepowerforums table and dumped it into a spreadsheet to filter by cell-count. I found that the options are all gas-filled. Again, I'm new to the standards in flashlight bulbs, but I assume that these are all incandescent. So I have some searching ahead of me. Before doing so, I'll check the bulb with a multimeter, as suggested elsewher, to make sure that it is indeed the bulb rather than the flashlight. Otherwise, I'm just wasting my time (though it has been educational).

By the way, can anyone comment on how normal it is for LED bulbs to be designed with compatible bases and unloaded voltages as incandescent bulbs?

AFTERNOTE: Darn, ohmeter test shows that the filament in the bulb is not broken. It's essentially a short, which jives with my understanding of incandescent bulbs. The filament only increases in resistance when it heats up. So this means that the problem is elsewhere. A voltmeter test of the 4-cell batter assembly shows 5.88 V, which is right. So the problem is the pushbutton switch or the conductors connecting the battery assembly to the bulb. If I can't find the problem and fix it, I will graduate to an LED flashlight.  Thank you all for educating me thus far.

FINAL SCOOP: It was difficult poking the ohmeter probes down there, but the problem turns out to be a bad connection between the spring at the bottom and the metal strip that goes down there from the push-button switch.  From visual inspection, the joint looks terrible, speaking from someone who has breathed in lots of solder flux in another life.  Really badly made.  An environmental crime.  The makers are off-shore, but I'm thinking that the manufacturing *process* was not designed for robust construction.

Since I'm going to graduate to an LED flashlight, there isn't even any point in saving the bulb.
« Last Edit: June 10, 2018, 02:22:03 AM by FlashLightUser »

Offline robo819

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I am not that up to date (or I guess out of date) with the incandescent bulbs. I left the halogen and Krypton long ago for the LED lights.

Probably the best source on this forum for information about any of the older lights would be "byfixer" (no quotations) as he collects and restores many of the older to really old lights (antique).

As far as the voltages you are talking about from  for the LED "bulbs" , I don't know of anything that might fit the bill there. There may be something out there that I am not aware of , but as a standard you have 3v , 6v , and 12v LED emitters , although many of those can be pushed well beyond their listed maximum output , or lumens , with the right know how and the right modifications. They need a "driver" and a MCPCB (Metal Core Printed Circuit Board) made for the certain emitter that you might be using for a given light. There are also many different types of drivers out there now , from the FET (near direct drive) to the buck drivers , constant current drivers and boost drivers , but that is something that takes time to try and explain out....lol

With the newer lights you also have many types of ways they can be wired with 4 cells. For instance the 4 cells you speak of could in in series , in parallel , in a 2s / 2p or a 4p and so on...........it gets confusing and that is all a whole other story though.

Some drivers for these newer LED lights are made to accept the standard Alkaline and NiMH cells , as well as the Lithium-ion cells in the same light , but the majority are made for the Lithium-ion cells only. The ones that can use either chemistry cells have a special driver in them specifically designed for that purpose. You also need to be aware that the Lithium "Primary" cells are different than the Lithium-Ion cells. The lithium primary have a higher energy density than lithium ion batteries. Lithium Primary cells use lithium metal as their anode unlike lithium ion batteries that use a number of other materials to form their anode. The lithium primary is also a one time use cell like the alkalines are , where the lithium-ion can be recharged many , many times over. One other point that even the long time users of lithium-ion cells (including myself) always need to remember , is that the lithium-ion cells are much more unstable and dangerous (when handled improperly) than the standard Alkaline and NiMH cells. With that being said , at the same time , the lithium-ion , if used right and proper care taken , are pretty safe to have and to use as long as you don't get too complacent and forget the safety rules of the cells , such as how to charge , how to store , proper voltages (minimum and maximum) and the list goes on.
There is a very good safety write up in the BLF forum if you have the time or want to read a little about that...........
http://budgetlightforum.com/node/45314

As far as throwing away the bulb or the light you have , since it sounds like you are very practiced in soldering , could you maybe get the part that is broken out of the light and solder it back together to get that light working again?

I would suggest either way that you move to the world of LED lights though , as there are so many out there now that are really just mind boggling when you start looking at the output compared to any of the older incandescent lights. The Maglite was king in its time , but now even some of the tiny AA sized lights (14500 in lithium cells) will give you as much as the old Maglites were doing. When you get into the 18650 and 26650 lights that are out there now days and start looking at 300 yards , to over a mile of throw from a few of them.......
Well I think you would be happy with the move to be honest.
« Last Edit: June 12, 2018, 06:48:09 PM by robo819 »

Offline FlashLightUser

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I did make te move to LED.  Quite happy.  The light is more uniform.

As for soldering, it was very much another lifetime.  I don't own much stuff anymore, including electronics and soldering equipment.  The broken flashlight is one-piece, and the bad connection is at the bottom.  I'd have to cut it open to access the problem, and that would destroy the flashlight.

Thanks for your thoughts!

Offline zulizera

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I was trying to replace one of my flashlight bulb and I totally damaged that flashlight. Although, gain some good experience and learn lots of inside. I have tested my led bulb using this Fluke 101 Review 2018: Basic Digital Portable Pocket Multimeter. Initially, I thought it was giving wrong signal but it didn't.
« Last Edit: August 07, 2018, 03:06:54 AM by zulizera »