Visible Condition of Arc Lamp Small 25W Flashlight Xenon Deterioration

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I assume there is an ignitor circuit as well as discharge supply. Conventional or electronic ballast/supply ? What would happen if you try a 100 watt industry standard one on the supply you have? I suspect the supply is voltage/current limited so won't be like trying to run a high watt filament lamp from a low W supply, and would arc at 25W but at what sort of colour though .

Ya got me.. I dunno squat about these lamps or driver circuits. The flashlight circuit is electronic, with a fairly large inductor (relatively speaking compared to the numerous other components), at the one output lead going to the lamp.

I've seen odd (to me) various specs indicating different lamp voltages such as 59V, 87V.. I'm guessing that means after the arc has been established.

I have an older video projector with a bad 350W arc lamp, but it was an obvious failure.. splattered onto the reflector. Replacement was ~$300+, I'm waiting for an alternative or will salvage the optics.

At the time, years ago, I asked here to see if anyone knew how to check the lamp firing circuit or defeat it, but didn't see any replies.

--
Cheers, 
WB 
............. 


"N_Cook"  wrote in message  
news:kkricr$9q8$1@dont-email.me... 
> 
> I assume there is an ignitor circuit as well as discharge supply. 
> Conventional or electronic ballast/supply ? 
> What would happen if you try a 100 watt industry standard one on the  
> supply 
> you have? I suspect the 
> supply  is voltage/current limited so won't be like trying to run a high 
> watt filament lamp from a low W supply, and would arc at 25W but at what 
> sort of colour though . 
> 
> 
> 
>

This sounds like a short-arc lamp. Probably runs on about half an amp at 60 V or so. Are you saying it has 3 terminals? I have seen some like that, the 3rd terminal is for the igniter that sends a spark in to get the plasma started. Note that these lamps can be quite dangerous. They have a high gas pressure inside when cool, and run up to several thousand PSI when running. They usually create quite an explosion when they fail. So, you want something between you and the lamp at all times when it is operating.

Do you have the entire device with power supply and igniter, or just the lamp?

Jon

Only 2 terminals, and definitely a short arc.. I can see the tips of the electrodes are real close, heh.

I'd read about the heat and pressure precautions, and have seen a projector arc lamp with a hole blown out the side of it, splattered onto the reflector.. so I wouldn't be experimenting with a lamp that wasn't in a safe enclosure.

The lamp is in a military surplus flashlight made by Xenonics.. the lamp replacement costs I've seen have been $400+ yeah, just the lamp (75W lamp with ballast from China $32 delivered, but I think I can guess which one is better quality).

The Xenonics lamp is adjusted for optimum performance with their specially designed reflector, so they say (although the head is adjustable for spot/flood lighting.

I've noticed with high powered LEDs that the placement and reflector shape is critical wrt throwing light. With a poor reflector, a powerful LED might not even produce a spot across a room.

Some reading material I stumbled upon, for anyone interested

-- Cheers, WB .............

I can't speak for your light, but I did just open the Maxabeam MBS-410 here, from around 1999.

There's a giant rod inductor feeding the HV side of the arc lamp. Around this are a few heavy turns of wire going to a spark gap (really) HV diode and a 5kV rated blue dipped ceramic cap. Feeding this is one of those Rf transformers wound on itself like a roll of twine with a little tunable ceramic slug inside. If it wasn't sealed in wax, I swear it's from some Zenith telvision set from the 1970s, with all the modules.

So it looks like something drives the tuning coil, that with the diode charges the cap and then the spark gap fires and that discharges into the heavy 5 turn winding on the inductor feeding the lamp. I'm going to guess that's the ignitor part. All these parts have red gylptal on solder sides and are sort of glued into place so I'm not going to distrupt them.

The low voltrage side of the lamp goes over to a section hidden in the read housing casting with at least two large power devices, bolted to aluminum spacers which are then screwed into the rear casting. I'm going to avoid messing with that for now, if I can get to the rear power connector. There are gaskets in places for fake moisture sealing, and the power connector flags is "sealed" to the casting with some sort of silicone "slime". A bunch of other screws that peice the extrusion of the body itself have no sealing of any sort. In there I can see one of those two ferrite cups style transformer about 7/8 inch tall. This must turn the ~ 12 volts into into whatever the lamp runs on.

The device that focuses the lamp is an actual RC servo. Brilliant, simple, hillarious. That pushes a rod that slides the lamp back and forth.

The electronics board slides out of the aluminum body extrusion and has banana connectors that feed the lamp. Nice design.

The PCB is conformal coated and the layout was done by hand. The largest cap is quasi name brand (Sprague), and the semiconductors don't have ground off numbers. There's a SMD microcontrller on a piggyback board taking the space of 28 pin DIP. Old school.

I could probably post photos if anybody is curious.

Wuuf! the Maxbeam looks like a monster, but the chart shows it weighs only

3.3 lbs. Is that weight correct?

The single-hand control to change from flood to spot would definitely be handy.

The adjustable strobe could be a cool feature. Xenonics and maybe others are working on high intensity lighting that pulses/strobes for riot/crowd control, according to something I read recently. Trouble is, eplieptic persons may end up going into seizure induced by flashes at a certain rate (so I've heard, I forget what the rate is).

The Nighthunter isn't a light you'd want to drop on your bare foot. The beam adjustment flood/spot is accomplished by turning the head, just like the Brinkmann mini flashlight I bought decades ago.

Pics of the NightHunter II innards with basic descriptions are in a Flickr Set:

The lamp's arc gap:

The circuit board is silkscreened with a date code indicating the 52nd week of 2004, which may just represent that version of the board.

There are a lot of China arc lamp flashlights on eBag priced roughly about $100.

I wouldn't have a clue about other lamps' specs, but a pair of car/truck HID headlamp bulbs with the balast/inverter can be had for a mere $12.

-- Cheers, WB .............

yeah, it's correct- but you need a battery pack or 12 volt power supply to run it. The standard nicad battery is maybe another 4 pounds or so, it's not too bad, but not something you'd hang off your belt. It has the typical generic nylon uncomfortable shoulder strap.

I've never seen and real proof that flashing lights disperse crowds. All the flashlight manufacturers say it's so, but none can back it up.

that board is far more complex than what maxabeam uses.

I wonder how anybody makes money on stuff that cheap.

The N-H II weighs 4.5 lbs with a battery and could be downright uncomfortable to carry for extended periods without the shoulder strap.

The version of circuit board I took the pics of is a bit more advanced than some other/earlier N-H II models. The pics show the version that includes a charging circuit, whereas some other models require an external charger/holder assembly.

The newer one can be powered by or recharged by external sources from

12-32VDC (so they say) by connecting a cable to the end cap connector, which the older ones don't have.

A 12V source may not be enough voltage to maintain an arc, as they don't work well from a 12V 5Ah SLA jumper pack power source. They do light reliably from the original 14.4V NIMH 4Ah battery packs (12pcs

4/3 N cells).

I think it's unlikely that cheap goods would be available if not for government subsidies at each end essentially resulting in free global distribution of low cost goods. The old addage was *it's cheaper to make those things over there*, but even if it was ever true, transport to the US, warehousing and national distribution here aren't reflected in the selling cost of these cheap goods. The Pacific is a big ocean and air cargo can't be cheap either.

I've read that mailing/shipping a small package to China is expensive (returning a defective product, for example), but when the USPS accepts items mailed via China Post, apparently it is cheap. Since eBag sellers in China commonly sell stuff for cheap with shipping included, this also suggests other economic factors are involved. I remember when eBag first set up commerce with China sellers, and reading how proud they were that they had accomplished (negotiated) the deals.. so maybe they're another investor in China trade.

Lately I've seen a number of articles stating that the constant flood of cheap goods from China is going to be drastically decreasing or slowly coming to an end.. we'll see.

-- Cheers, WB .............