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How can I by-pass power supply from old overhead projector? Answered

I am wondering how I can use the power supply of the overhead projector and also use the High voltage supply it comes with. It does seem to be dependent on other circuitry and a quick Google search doesn't reveal much about this. The power supply needs feedback from a thermistor and a motherboard that is attached to the supply with a dual row pin of total 20 pins. The motherboard needs to be there in order for anything to work. I am wondering if there is a pin I can short similar in fashion to a computer power supply. 

Any suggestions?

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iceng

4 years ago

I make large Ozone generators for restaurants, cabs and night clubs.

The basic circuit is a minimum 6KVAC neon xfmr and chicken wire in a 8" dia 24" long electric conduit segment, trivial circuit.

You might trickle water across a swamp membrane while blowing O3 with a squirrel cage fan.

Osha does not get involved until you produce over 50 lb of the gas which has a half life of 30 min.

BTW I hope you know about clicking the best answer.

A

OzoneCkt.jpg
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Hendrik0360iceng

Answer 4 years ago

Hi, thanks for the reply, I am more interested in getting this power supply, which I already have, to work as the components are all there. I might have to rip out the components and just add the proper voltages myself. I also was just playing with removing as much components and still having it to work when I was looking at the lens assembly and thought about using this as a microscope. I remove the digital image producer, which it blows up on a screen. Now you can just insert anything to magnify. But I am still interested in knowing how to get the high voltage working without tearing it apart.

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icengHendrik0360

Answer 4 years ago

You mentioned the high voltage was to momentarily start a breakdown in the gas in a tube and allow current flow to begin at a much lower potential.

As such I doubt the unit could sustain the high kilovoltage to make a practical ozone generator without serious electrical damage and fire !

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Hendrik0360iceng

Answer 4 years ago

Yes, its what I am worried about. I think the kilovolts should be fine, but I am assuming they are using a few Kv to start the lamp, but the sustained amps that could be an issue. I think Ill just tear out the necessary components and find datasheets on current limitations etc. maybe there is some use to them yet. Otherwise, scrapyard it is.

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Downunder35m

4 years ago

Good models check the current going through the lightbulb as well as the temp inside the projector and lamp housing.

Without some reverse engeneering you can't just use the power supply for something else.

What exactly are you trying to do? Re-use the power supply for something different, modify the projector?

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Hendrik0360Downunder35m

Answer 4 years ago

I am trying to use the high voltage that is coming out of the power supply to generate a corona effect for a ozone generator that I would like to use to treat our well water. Now I am starting to realize that the high voltage might be a temporary operation to start the lamp, which would require further tampering which could be difficult. But maybe someone has done this before. Thank you for your quick response Downunder35m

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-max-

4 years ago

Well it depends on how the engineers have designed it, and generally things like that are proprietary and closed-source. You may end up having to reverse engineer the power supply section to get it to work without protection and silly things like that. I would assume there is an 'enable' pin somewhere, perhaps connect that to a +5v rail though a current-limiting resistor, or to ground and see if anything happens. You may be able to find some data on the pins on the silk screen, though then I guess it would have been obvious. I think ATX power supplies use a light purple wire as an enable pin, not sure though.

It may be a simple pin that need to be tied to a voltage rail, or it could be a complicated parallel or serial interface between the digital mobo and power supply board. After all, somehow the OSD with all those brightness controls and eco modes has to be able to dictate how the bulb is driven, and how hard.