UV ballast - mystery wire?

Electronics
#1

Got a troubleshooting help request. (Troubleshooting devices without schematics stinks, doesn’t it?)

The picture below shows two chokes. The upper one goes to the pretty little tube up top, and can be ignored.

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The lower one takes in 18VDC from the wee plug there, and runs to two terminals, as is fairly visible. On the other side of said terminals is a socket for a UVC bulb – much like that nicely toasted one pictured below the component… I’m sure you guys see where I’m going with this.

Choke’s got a short in it (significant enough to generate enough ozone to smell significantly, nearly immediately) so I’m loath to do a lot of powered testing and just make the problem worse. It’d be nice to just swap this sucker out with another 18VDC UVC ballast.

But then there’s that extra wire… I’ve never seen a ballast with one extra wire, and have no idea where it’s supposed to run to. Which is the mystery I’m trying to solve. Yes, it came with that sheath – but there’s nothing that would get particularly hot in this device anywhere where I could imagine that wire running. (It’s an air purifier – small motor, couple of vanes, ozone generator because it’s old and ozone generators hadn’t been tied to all that harmful stuff yet, the UVC antibacterial bulb, some control electronics. Pretty simple beast.) Hesitant to apply voltage as I stated before, plus if the choke’s shot I can’t really ensure any voltage at the wire would be correctly representative anyway. Dead-circuit continuity is open from the wire to basically everything I can put a probe on – I imagine those blue blobs in the white solid epoxy-ish stuff that look suspiciously like mica capacitors probably have a lot to do with that. Though of course, whatever that white goop is in that thing makes it impossible to probe – or identify – much of the circuit.

Okay, that’s my brain dump of the little I know. Probably tl;dr – thanks, if you’ve made it this far. Short of throwing this thing away (exceedingly tempting, except that apparently it inexplicably goes for around $200 new, I’m told? sigh), and seeing as the manufacturer doesn’t seem super keen on releasing schematics to me, any suggestions on how I should proceed?

#2

Whats that black spot to the right of the transformer? It almost looks like a hole. Maybe I need more characters.

#4

I think that runs along the ballast and plugs into the ballast with the bulb? I’ve seen that in other uvc lights unless I’m just replacing curved uv bukbs in my mind with this. Do you have the make model and manufacturer details at all?

#5

Looks like a black spot in the “epoxy” up close too - maybe got caught in there while drying? Can’t feel the spot if you run your finger across it; whole thing’s smooth. Seems too small to be a component. But yes, that whole area is solid.

Remember that first ballast that goes to the pretty tube, that I said could be ignored? That’s the ozone emitter. :slight_smile:

Of the device? It’s a Surround Air XJ-3000C (the “C” and “D” series are functionally identical, is my understanding, in case you manage to hunt down schematics for either). The brand may have some knockoff related brands as well, and their schematics may work too - I’ve only recently started digging into the brand history, so not sure, but there seems to be some “history” in their history… We’ll see.

Also, not sure what you meant by “plugs into the ballast” - it runs from the ballast, doesn’t it?

#6

Yeah me not so good with words especially when it comes to electronics, I tend to call everything the same thing. I meant I believe that wire runs parallel to the bulb, attaching somewhere by the end of the bulb. There’s a great chance that is completely wrong but this setup looks real familiar and I don’t know why. I’ll see if I can rummage up some schematics

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#7

It could be another tap. I would check the resistance from one to the others. That might tell you.

#8

That’s what I thought at first – but nope. Meter calls it an open circuit, measured to either terminal point on the choke side.

#9

That’d be fantastic! Let me know if you find anything. I have no context for anything quite like this to go off of, so anything similar would help.

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#10

Sorry, my buddy does small appliance repair and has access to a huge schematics db but he couldn’t find it anywhere :sweat:

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#11

No worries. Thank you for trying. My resources came up empty too, so the only source is likely to be the manufacturer – and they don’t seem real conducive to sharing.