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Author Topic: Official Machlett neon bulb thread  (Read 11088 times)

Offline robertc

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Official Machlett neon bulb thread
« on: September 27, 2007, 06:48:05 am »
You may have noticed that Tim has recently posted details about this extremely rare Machlett neon bulb from the 1930s:

http://bulbcollector.com/gateway/Gas_Discharge_Lamps/Neon/Machlett/image/ne0164.jpg

There have been several for auction, and I was lucky enough to win the first couple. These bulbs are particularly interesting because they rely on a positive column discharge, rather than the normal negative cathode glow. Tim has kindly located the patents for these:

http://www.google.com/patents?id=kp1FAAAAEBAJ&dq=1945285
http://www.google.com/patents?id=k51FAAAAEBAJ&dq=1945286

The first patent appears to match the bulbs I have, because the magnesium starting strip is continuous and isolated from each electrode, rather than being joined to the electrodes and broken in the middle. The bulbs have a neon fill (confirmed by energising with a plasma globe), and appear to be rated for 220V operation.

Unfortunately, they don't actually work as intended, because the internal resistors have gone open circuit, and for all I know, this may apply to all the bulbs that have been sold recently. From what I can see, the resistors appear to be carbon rather than wirewound, so they have probably failed with age rather than use. There are also greenish deposits on the lead wires near the resistors, suggesting age as a factor.

Is there anybody out there who would be willing to undertake a repair on one of these bulbs? It would entail replacing the resistor and re-cementing the base, with the added difficulty that I have no idea of the correct resistor value. Alternatively, just replacing the resistor with a wire link would allow me to experiment with an external resistor, and at least I would have a working bulb at the end of it. There is of course, the risk that the lead wires could break off entirely, but I am willing to take this, as I have a couple of these bulbs and would only intend to repair one of them.

btw. There is one remaining bulb for auction, so if anybody wants to bid for it, here's the link:

http://cgi.ebay.com/Vintage-OLD-Neon-Incandesent-Light-Bulb-Weird-Strange_W0QQitemZ140161824262QQihZ004QQcategoryZ1405QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Beware that the auction prices have been steadily increasing, from $78 to a whopping $182.

Robert
« Last Edit: December 04, 2007, 09:12:40 pm by Tim »

Offline Tim

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Re: Extremely rare Machlett Neon bulb
« Reply #1 on: September 27, 2007, 09:52:13 pm »
Welcome to the forum Robert.

Consider this an obscure historical sidebar about Machlett that someone may find interesting.  I don?t know much about the company and have only just begun to dig into their history.  Of specific interest to me is ?Rainbow Light, Inc.? which appears to have been some kind of spin-off of Machlett Labs, or pehaps even pre-dates Machlett Labs.  The sleeve on my bulb was marked with ?RAINBOW?, which is how I found the above two patents using some creative searching on Google Patents.  After looking at some other patents assigned to Rainbow, it becomes apparent that the company was focused on gas discharge devices.  Here?s a very old newspaper article that I found which may explain the use of the name ?Rainbow?.

Quote
MANSFIED NEWS (MANSFIELD, OHIO)
March 25th, 1927

NEW DISCOVERY TO BE AID TO AVIATORS

NEW YORK March 25 (AP)

The New York American in a copyrighted story today says a new discovery in action of electrons when thrown with terrific force against a mirror of cesium, a rare and costly metal, is to be enlisted to aid aviators flying in thick weather or in fog at night.

Raymond R. Machlett, scientist and Cornell alumnus, the paper says, has devised, after several years of research, an ionic discharge tube twenty-seven feet long filled with neon gas which lights and widely diffuses ?rainbow light?.

Current of 500 milliamperes is passed between an anode and an electrode through this super-tube, an achievement which is said to surpass any previous experiment with neon gas.

In a similar article found, also from 1927, it mentions Raymond Machlett's "Rainbow Ray" to describe the same fog penetrable long wavelength light.

And finally, here's a picture of Ray Machlett at age 26, taken from one of the 1927 newspaper articles describing the neon fog beacon.
« Last Edit: September 27, 2007, 09:57:29 pm by Tim »

Offline robertc

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Re: Extremely rare Machlett Neon bulb
« Reply #2 on: September 28, 2007, 04:39:27 am »
Hi Tim,

Thanks for providing this info. I also found an interesting article on the Time magazine website:

http://www.time.com/time/magazine/article/0,9171,740414,00.html

This is dated September 29, 1930, and the text is reproduced below. I particularly like the suggestion that neon could replace incandescent bulbs, because the latter were considered too bright, and didn't give off "healthful ultra violet rays".


Neon Tubes Improved

When people see an advertising sign in which the letters or designs are formed by slender glowing glass tubes, they may know at once that it is a neon light sign. Although effective as displays, these lights are expensive because of the high voltages necessary to start them glowing. Last week Raymond R. Machlett, 30, Manhattan electrical engineer who, when he was 26, was one of the first to develop a commercially satisfactory Neon tube, announced that by altering the construction slightly, he had been able to light a neon lamp with a 220-volt current, the ordinary household voltage. Present tubes require a 10,000-volt current, expensively stepped-up from service current by transformers.

If Inventor Machlett's improvement is a success, it may be possible to use neon lamps in homes and offices to replace incandescent bulbs. The brightness of the incandescent filament is usually too intense, requires lamp shades. Neon light is diffused, needs no shading. It more nearly approaches daylight, gives off healthful ultra violet rays.

Though "neon tube" is the term commonly applied to all kinds of lighting tubes containing luminous gases, not all such tubes contain the gas neon. The majority of signs first made four years ago used only neon gas, which gives a red light,

But scientists had already learned that by using other gases they could get other colors?argon & mercury vapor for blue, the same combination in a yellow tube for green, carbon dioxide for white. The gases are confined in the tubes at low pressures (5 to 10 millimetres, compared to 760 millimetres in the sea-level atmosphere). The gases are made to glow by an alternating electric current flowing through them. Because of the penetrating quality of the infra-red rays given off, neon lamps are used as fog beacons, airfield lights.


Offline robertc

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Repair of old Machlett neon bulbs
« Reply #3 on: October 15, 2007, 06:51:36 pm »
Apparently, most of these old bulbs that were recently sold on ebay have failed in the same way as mine (ballast resistor going open circuit). I am very keen to get one of mine repaired, and I can imagine that other owners would be interested as well.

So, is there anybody out there would be willing to undertake such a repair, removing the base, replacing the resistor and re-cementing it? I for one would be willing to pay a decent sum, as long as the repair was done to a professional standard.

Alternatively, can anybody supply some proper bulb base cement, so that I can have a go at my own repair?

Robert.

Offline Chris Kocsis

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Picture of Lighted Machlett Rainbow Lamp
« Reply #4 on: November 13, 2007, 10:18:00 am »
Hi all,

Note: The text that follows has been edited from what I first posted because I've learned I was making mistakes with my measurements and calculations.

There have been a couple of threads about the unusual Machlett Rainbow neon lamps that surfaced earlier this summer on eBay.  Several were sold and the majority are duds. Some of us buyers of the duds theorize that that external resistors have gone bad and one of us has a scheme afoot to attempt a repair. 

In an attempt to find the value of the resistor in my working lamp, I set the bulb up with some meters attached, to measure current consumed and voltage applied.  My best guess, after reviewing what I originally said and finding mistakes in it, is that the resistance might be on the order of 3,000 ohms.  It turns out that you can't use Ohm's law to calculate the resistance from the voltage and current.  You have to take into account the firing voltage and the best method may simply be trial and error.  For one thing, there is no ideal or standard brightness to a cold cathode lamp -- the brightness depends on the voltage and has an inverse relationship to longevity. 

Anyhow, leaving the calculations aside for someone who really knows what he's doing, here is a picture of my lamp at full operating voltage of 220. 

If any reader owns another working one of these lamps, please reply -- especially if you have one of the ones that were apparently made with an argon fill or were made for operation on 110 volts.  I am sure that as progress is made in the repair of the nonworking ones we know about, that information will be posted to the forum.

All the best,

Chris Kocsis
« Last Edit: November 15, 2007, 10:27:39 pm by Chris Kocsis »

Offline Chris Kocsis

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Re: Picture of Lighted Machlett Rainbow Lamp
« Reply #5 on: November 13, 2007, 10:37:52 am »
A couple more pictures: the bulb showing the first tiny, steady glow at 141.5 volts and the lowest full firing at about 150 volts.
« Last Edit: November 15, 2007, 10:37:28 pm by Chris Kocsis »

Offline Tim

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Re: Picture of Lighted Machlett Rainbow Lamp
« Reply #6 on: December 04, 2007, 08:59:39 pm »
I finally picked up a 220 volt variac, so here are two pictures of my bulb lit at 180 volts AC.  Initial glow isn't noticed until 170 volts is reached, seemingly higher than Chris' bulb...

Since there were several threads relating to these bulbs, I decided to merge them all into one thread for easier reading.
« Last Edit: December 04, 2007, 09:10:21 pm by Tim »

Offline silvertoneman

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Re: Official Machlett neon bulb thread
« Reply #7 on: July 20, 2008, 11:06:49 am »
I am a new user of this site, and new to the bulb-collecting world, so please forgive me if I seem a bit ignorant. The other day at a thrift shop I bought, for a quarter, one of the Machlett rainbow bulbs. It was buried in a box of Xmas tree bulbs.  It's marked "Rainbow" and "220V". Luckily, the ballast resistor is good, and it performs perfectly. When I can get hold of a digital camera I will send a picture of it in operation. I guess I was just darned lucky that day!! I had always thought that Machlett was a maker of X-ray tubes and nothing more....Dave Salny Anderson SC

Offline robertc

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Re: Official Machlett neon bulb thread
« Reply #8 on: July 20, 2008, 06:19:27 pm »
Hi Dave,

Sounds like you were extremely lucky to get such a rare lamp for such a good price, and in great condition, too. It also sounds like you may have the only known example with markings still visible.

Regards,

Robert

Offline silvertoneman

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Re: Official Machlett neon bulb thread
« Reply #9 on: July 20, 2008, 11:24:02 pm »
Hi Robert: Thanks!! I thought it was a neat bulb when I spotted it; I thought at first it was a gaseous rectifier for a 1920's radio power supply. I am amazed that what I have is rare. I had no idea until I checked out this site!! I'm very new to this and only have about twenty bulbs so far, but I guess I'm off to a good start. I will send a picture of this one ASAP...Dave

Offline Tim

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Re: Official Machlett neon bulb thread
« Reply #10 on: July 24, 2008, 10:29:30 pm »
The other day at a thrift shop I bought, for a quarter, one of the Machlett rainbow bulbs. It was buried in a box of Xmas tree bulbs.  When I can get hold of a digital camera I will send a picture of it in operation.

Great find!  Please post some pictures here when you get a chance.  I would like to see it and compare the electrodes with the others.

I had always thought that Machlett was a maker of X-ray tubes and nothing more....

I thought the same too.  This is part of the reason that I find these bulbs so interesting!

Offline silvertoneman

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Re: Official Machlett neon bulb thread
« Reply #11 on: July 28, 2008, 11:33:52 pm »
I've taken a picture of my Rainbow bulb in action; now all I have to do is figure out how to get the picture onto this site! I'm a complete idiot when it comes to digital cameras, and I don't have the directions!!!
By the way, the bulb is marked as follows:

RAINBOW        220V     5W

Offline Tim

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Re: Official Machlett neon bulb thread
« Reply #12 on: July 31, 2008, 02:27:56 pm »
now all I have to do is figure out how to get the picture onto this site

It's simple.  When you post a message or reply just look for the "Attach" box and hit the "Browse" button to fetch the file off from your computer.  Keep the pictures under 196kb in file size and make sure they are in typical "JPG" format and you should be fine.  You can attach up to six pictures per posting.