Bypass Protection mode on projector

Firstly, Did you use a 84 ohm resister rated at 145 watt, it would look like a small heater element. If you used a standard 1/2 watt resister I not surprised it had a very short life.

I hope the projector has some protection against short circuits in the globe, because that is what a 12 volt 145 watt globe will look like at 110 volts a resistance of about 1 ohm, I expect you have destroyed the lamp driver circuit in the projector.

Use the correct globe, or find a suitable load.

Peter.

yes, thankfully it does have a small circuit breaker in the unit and it did trip. The motivation behind this is that I don't have 400 dollars laying around for a new bulb. If that would be an option in the next month on two I wouldnt even mess with it. I do appreciate the info though.

Hello garyboyce

What you are trying to do, is really quite impractical.

The amperage of the 110 Volt lamp is quite small, and is designed for use in the circuit, by the Manufacturer.

The 12 Volt lamp with the same output as the 110 Volt lamp, will require approximately 9 times the current of the 110 volt lamp, and no matter how you try it, you may well permanently damage the projector.

so, you are better to save your dollars, and purchase the correct lamp as the projector maker's have specified.

Hi-tech equipment is often easily damaged, by owners who try to 'save money' by trying an unsatisfactory spare.

I do appreciate that these type of projector lamps are very expensive, but if you use one of these projectors, it is assumed you can afford the correct spares.

Kind Regards....

Sparkstation is totally right, he probably got his name by doing something similar.....

Look for the correct bulb on ebay, in Europe they have the best prices.

For anyone who does not yet own a video projector, check the price of the lamp before buying, also its projected (pun intended) lifespan.....

Throw that piece of shizit out the window. Projectors are about the same money as you bulb these days. www.tigerdirect.com

You took the words out my keyboard...Nothing else should be said on the subject.

Have rated you with good answer.

Wangito.

Did you use a power resistor that could dissipate at least 145W?

To handle the power, it will be a pretty substantial resistor (or bank of them sized appropriately) and probably a big heat sink and a fan.

A 1/4 watt resistor will of course, fry immediately.

what if you just put the high side of a 10:1 xfmr in place of the 110v, 145w then at the low side you will have (approx) 12v with about 13 amps available for your 12v bulb. Don't bother trying to rectify the voltage for the 12v, the bulb won't care.

The transformer would definitely be outside of the projector as it will have to be substantial, plus the extra load and the rectifiers for the 12volt (if DC?, as I presume) system will also be substantial.

I think what is being attempted is this :

Use 12v dc halogen projector bulb for car- using outside power source (ie 12v battery) - not internal regulated power circuits

fool projectors complex ;I need you to spend 400.00 circuit (because this is the actual revenue source for maker/like inkjet printer and ink)

Some engineer with knowledge of the oem Hydride lamp needs to show a circuit that imulates the high (how much?) intial resistance than falls to the on state resistance (how much?) to fool the circuit that allows the projector to think that the bulb is in working order so that it can cycle and operate.

I would look around the net for lamp driving circuits to gather an understanding of how these are typically driven.

Ultimately the lamp load is signal is present in your projector as a low level signal that can be played with without dissipating as much power as the lamp replacement resistor.

You need to reverse engineer your lamp driver.

Indeed you need a good electronics understanding to play with this type of circuits without killing it or yourself...

Hey Guys, Thanks for all the input. Especially the comments about how to actually go about the project. I will be buying a new projector. I have found a model that better suits my needs and has a much cheaper bulb.

Once again, Thank you.

Good Choice.

I have a friend with a rear projection tv, no job, and a blown bulb. Only reason I was pursuing.

Well maybe the motivatiobn of not being able to watch TV will get my friend off the couch and into a job!

NOT Likely, but we can all have a dream.

People interested in projectors, can also take a look at this 3M pocket projector that is due to be launched. Check this out:-

http://www.kanbal.com/index.php?/Electronics/pocket-projector.html