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NE3 neon bulbs in antique meter-what are they for?

Greetings All, I was given an old meter that was originally bought by the US government. It was missing some labeling so I don't really know yet what all it can do. It can measure some kind of radio signal (I think) because it has a probe that connects to the kind of fittings I've seen on radio gear. The fittings are large co-axial and the probe plugs into the fittings. The probe for this has some kind of tube (valve for the Brits) in it with a metal point coming out of the end which makes contact with what looks like a gold plated piece of bent flat spring. I know this is not a very good description and I will be posting pictures of it on the Metalworking.com web site. This device is about

6" x 9" by 8" tall. It had gotten wet so I took it apart to dry out the internals. The meter movement seems to have stayed dry but other stuff inside got wet. Inside the thing are two what I think are NE3 neon bulbs. The sockets for them are marked NE3. I was able to find some on the internet for sale but no pictures. I have two questions about these bulbs. First, since any light coming from these would not be visible when using the meter what could their purpose(s) be? And second, how can these bulbs be re-glued into their bases? I was going to remove them from the sockets to clean the contacts in the sockets but the glass bulbs are loose in the brass bases. I could buy new ones but at anywhere from 9 to 15 bucks apiece, plus shipping, it's too much money to spend on something that I don't know will even work when plugged in. For that matter the meter is might release all it's magic smoke when plugged in the first time. It's interesting that the power supply section is made to be swung out when the case is removed from the meter. Printed on the chassis inside are instructions to remove two particular screws to pivot open the power supply. Anyway, thanks for any help and insights. Cheers, Eric R Snow
Reply to
Eric R Snow
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The neons sound like static protection to the input (They fire on a voltage of around 90v each) , mebbe it was used to measure RF ? The glass tubes can be glued back into their bases with araldite or similar.

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Regards ......... Rheilly Phoull
Reply to
Rheilly Phoull

I've also seen this neon threshold exploited for use as a voltage regulator. And because it takes less voltage to maintain the discharge than to start it, neons were sometimes used to make simple relaxation oscillators.

Best regards,

Bob Masta dqatechATdaqartaDOTcom D A Q A R T A Data AcQuisition And Real-Time Analysis

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Home of DaqGen, the FREEWARE signal generator

Reply to
Bob Masta

Thanks to all of you who posted answers to my meter questions. I will post pictures on the Metalworking.com web site in a couple days. I'll post the link here when they show up. ERS

Reply to
Eric R Snow

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Sounds like an R.F. millivoltmeter. The probe containing a rectifier diode type valve that gives a DC out proportional to the RF voltage at the connector. With small RF signals, the DC out may only be a few mV and could be the reason for the neons. They are possibly used in conjunction with a couple of CdS photocells to 'chop up' the DC (at a low frequency) to allow easy AC amplification and finally drive the meter. john

Reply to
John Jardine.

Greetings John, Your description matches this device. It has mills, DC, and Ohms. The NE3 bulbs do not have any CdS photocells associated with them. I powered up the device and only one of the two neon bulb lights up. There tubes, I think electrolytic capacitors, and one power transistor in this thing. Do you know if it would be worthwhile to try to make it work again? The meter movement itself seems fine. Is it maybe something that a radio person could use? And is worth the cost of shipping? It is just a curiosity to me. Thanks, Eric R Snow

Reply to
Eric R Snow

diode

Eric. G'day. Sadly, I'd say it sounds like it's a junker. Great value and benefit in it's time but now outpriced, outperformed, outgunned. The neons look like they're there as voltage stabilisers. Beyond that, the meter is the only bit worth saving. Over the years I've found I can't even give this kind of stuff away and had to scrap tons of it. All of it magnificently engineered, using the finest materials and doubtless classics in the making. Would need though a secure warehouse and another 40 years of careful ageing and TLC :) john

Reply to
John Jardine.

That's what I thought. It has a really nice bakelite case. Maybe I'll keep that part if I can't find someone who would like the whole thing. ERS

Reply to
Eric R Snow

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