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Surge protector neon lamp replacement

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themaritimegirl

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I've always wanted one of those generic pizza box-style surge protectors (the ones that look like this), and I'm thinking of getting one on eBay. Knowing that at least one of the six neon lamps in the switches will be burned out, I ask, has anyone ever replaced a neon lamp in one of these before? Or in anything with a similar lighted switch? If so, was it difficult? I fear that the switches are sealed in such a way that I would destroy one trying to get it apart.
 
Yup--you need to use a "mini" neon lamp, however, not an NE-2-sized one. Remove the switch from the housing and insert a small screwdriver on each side of the actuator (rocker)--it's held in by pressure from the sides on the pivot point. It's hard to explain, but it's simple. Carefully watch for springs and bits that may fall out.

These look to be the right ones

Note that neon lamps require a ballast resistor--usually about 30K-47Kohm in series.

It may be easier just to order replacement switches with something like this and avoid the frustration of getting the rebuild right. Ebay search keywords "illuminated rocker switch".
 
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Thanks for the info! I wouldn't be surprised if they turn out to be standard switches. It's just impossible to tell without seeing inside one.

I've bought one anyway, so we'll see how it goes when it comes!
 
Yanno, I've always wondered about the neon lamps in surge protectors. I always thought that
if they started flickering that the surge protector component (An MOV in most cases) was
"used up", or had absorbed enough spikes so that it required replacing, as evidenced by the lamp
flickering - a voltage spike got through and damaged the lamp.

Am I making sense or making gibberish again?
 
A real surge protector uses a gas-discharge tube, not a neon lamp--and they're rarely visible, since they're usually made of opaque ceramic. Viz,

Ceramic-Discharge-Tube.jpg


The things in the switches are plain old neon indicator lamps.
 
Chuck,

I think you misunderstood me - I wasn't suggesting that the neon lamp was the surge protector, but a clear indication that the actual surge protector component (MOV, gas discharge, etc) was blown or used up. IIRC, neon lamps were pretty fussy about voltage spikes and could be damaged quite easily by one.
 
My experience with those little power centers has been that the lamp indicates power applied (i.e. a simple indicator) rather than indicating anything about surges. Given that a surge protector is an open circuit under normal circumstances, I suppose one could use a neon to indicate when one was shorted, but more gas-discharge surge suppressors don't fail that way--and should that occur, any protective fuse would be blown. Bussman used to make AC fuse holders that incorporated a small neon in parallel with the fuse--it would illuminate when the fuse was blown.

Do you have a schematic of one of these things? That would surely solve any issues. For short-term overvoltages (spikes), neons are actually quite robust.
 
There are a couple of lamp arrangements used. If it's in the rocker switch, it's almost certainly just a power indicator. The neon lamps start to flicker as the cathodes get poisoned and the striking/maintain voltage of the lamp starts to increase.

You'll sometimes see a "lit when protected" lamp, most often a LED, that indicates when the protection circuit is knocked out -- this is usually found in cheaper surge suppressors that use only MOVs. As a MOV takes more spikes, it starts conducting within the normal line voltage range. This makes it get hot. Eventually, if you just had the MOV across the line, it would overheat and smoke, or burn, or otherwise destroy itself. To prevent that, there's a thermal fuse in series with the MOV, which opens (permanently) when the MOV starts drawing too much current. That's when the "lit when protected" lamp will go out, and it means your surge suppressor is now just a power tap.

There are also wiring fault indicators, which just tell you if there's a hot ground, reversed polarity, et c. Depends on the manufacturer as to what the lamp means. When it's illuminated, there's some sort of problem with the receptacle you're plugged in to. Note that the lamp being off doesn't necessarily mean everything is OK!
 
Just so--see my comment about a lamp across the fuse indicating a fault. But a power indicator lamp would serve much the same purpose.

Most of the made-in-China/Taiwan power-center affairs that I've seen use a single MOV as a suppressor and the switches have simple indicator lamps to show which rocker switch is in the "on" position. I've got simple 6-outlet power strips that have a rocker switch indicating the same thing.

Neon bulbs have a finite life, as glitch mentioned--on a non-functioning lamp, you can often see the evaporated electrode metal as a dark stain on the bulb. I confess to having replaced AC neon indicators with a small diode-capacitor-LED combination--they should last longer in theory, but probably not be as tolerant of voltage spikes.
 
Yeah, the big box of NE-2H bayonet base lamps I've got have a built-in 33K resistor in the base.
 
OK, NE-2H are not the same.
A straight NE-2 is rated at 0.6ma max it shouldn't be run
at max. Assuming the maintaining voltage is high of about 60V
and the ac line was 125V, for 0.6 average, I get 108K.
Those mini NE-x lamps are 0.3ma to 0.1ma someplace.
One could experiment. You really don't need more current
than lights the full length of the rod.
Dwight
 
Yes, it depends on the lamp.

However, I probably wouldn't bother with re-lamping commodity switches like those on the pictured unit. It's simple enough to replace the switch.

The last switch I re-lamped was a 20A DPST rocker, so the NE-2H was probably the right lamp for it.
 
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