Sites: GlobalSpec.com | GlobalSpec Electronics | CR4 | Electronics360
Login | Register
The Engineer's Place for News and Discussion®

Previous in Forum: urgent: please give me the schematic for FM broadcasting station.   Next in Forum: 85 HDTV Vehicles will be put into use
Close

Comments Format:






Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







14 comments
Associate

Join Date: May 2008
Posts: 29
Good Answers: 1

Bypass Protection mode on projector

07/24/2008 7:33 PM

Let me start by saying that i have already tried searching for the answers to my question. (about 5 hours)

I am trying to simulate the load of a 145 watt 110 volt nickel metal halide bulb that puts out 2500 lumen. I used ohms law to calculate it and came up with 84 ohms. When i tried that resistor it just burnt in two. There is a ballast connected to this lamp but i cant find any information on it. Not to mention, I dont know how to take that into consideration when I am trying to figure the load. If some one could help me figure this out I would be very appreciative.

What I am trying to do is use a 12 volt haligen bulb that puts out 2500 lumen in the projector. I dont have any problems with that side of it. The problem comes in when the projector looks for the bulb and (I assume) doesnt see the load from it.

Projector: PLV-Z4 Sanyo

Original Bulb: 145 watt 110 volt nickel metal halide 2500 lumen

New bulb: 12 volt haligen 2500 lumen

Also, I do have the service manual if anyone needs that for reference.

__________________
garyboyce
Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Active Contributor

Join Date: Jul 2008
Posts: 11
#1

Re: Bypass Protection mode on projector

07/24/2008 8:22 PM

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.

Register to Reply
Anonymous Poster
#2
In reply to #1

Re: Bypass Protection mode on projector

07/24/2008 11:14 PM

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.

Register to Reply
Guru
New Zealand - Member - Interested in everything- see my Profile please APIX Pilot Plant Design Project - Member - Member Engineering Fields - Electrical Engineering - Member Engineering Fields - Power Engineering - Member Engineering Fields - Civil Engineering - Member Hobbies - Musician - Autoharp and Harmonica Hobbies - Hunting - Member Hobbies - Fishing - Member

Join Date: Nov 2007
Location: Christchurch, (The Garden City), South Island, New Zealand
Posts: 4484
Good Answers: 226
#3

Re: Bypass Protection mode on projector

07/25/2008 7:00 AM

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....

__________________
"The number of inventions increases faster than the need for them at the time" - SparkY
Register to Reply Score 1 for Good Answer
Guru
Popular Science - Weaponology - New Member Safety - ESD - New Member Hobbies - Fishing - New Member

Join Date: Sep 2006
Location: Near Frankfurt am Main, Germany. 50.390866N, 8.884827E
Posts: 14154
Good Answers: 139
#11
In reply to #3

Re: Bypass Protection mode on projector

07/27/2008 5:47 PM

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.....

__________________
"Better to remain silent and be thought a fool than to speak out and remove all doubt!"
Register to Reply
Anonymous Poster
#4

Re: Bypass Protection mode on projector

07/25/2008 5:25 PM

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

Register to Reply
3
Power-User

Join Date: Jul 2007
Location: Somewhere in the hills of Pennsylvania, I think.
Posts: 248
Good Answers: 4
#5

Re: Bypass Protection mode on projector

07/26/2008 12:40 AM

Metal halide bulbs are arc lamps having a very high electrical resistance in their off state. During operation, the ballast controls the operating voltage and current and the lamp can be considered a short circuit. A halogen lamp is a resistance lamp similar in operation to a standard household lamp. The two are not electrically interchangeable. If you want to use a halogen in this projector, you will have to remove the metal halide lamp's power supply/ballast, and substitute it with whatever you plan to use to supply the 12V to the halogen lamp you plan on using. You'll also need to select the right halogen lamp that is suitable for use as a projection lamp. If fact, there are many things to work out when doing a retrofit of this kind. Much too much to discuss in a paragraph or two. Best advice is to "bite the bullet" and stick with the original setup.

__________________
I'm somewhere between the age of thirty-something and Alzheimer's. I just can't remember where!
Register to Reply Good Answer (Score 3)
Guru
Hobbies - HAM Radio - CE3AM....4X4SW....CE3NSW

Join Date: Aug 2006
Location: Santiago Chile.
Posts: 845
Good Answers: 7
#10
In reply to #5

Re: Bypass Protection mode on projector

07/26/2008 10:39 AM

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

Have rated you with good answer.

Wangito.

__________________
Never trade luck for skill.
Register to Reply
Anonymous Poster
#6

Re: Bypass Protection mode on projector

07/26/2008 1:15 AM

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.

Register to Reply
Commentator

Join Date: Oct 2007
Location: Bass Lake, California
Posts: 62
Good Answers: 1
#7

Re: Bypass Protection mode on projector

07/26/2008 2:41 AM

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.

__________________
Some days you're the pigeon, some days you're the statue.
Register to Reply
Commentator

Join Date: Jun 2007
Location: Inverness, Florida
Posts: 87
Good Answers: 3
#8
In reply to #7

Re: Bypass Protection mode on projector

07/26/2008 6:15 AM

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.

Register to Reply
Guru
Canada - Member - New Member

Join Date: May 2006
Location: Montreal, Canada
Posts: 636
Good Answers: 11
#9

Re: Bypass Protection mode on projector

07/26/2008 7:15 AM

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...

__________________
''What the hell has my ass got to do with magic?" Don Quixote
Register to Reply
Associate

Join Date: May 2008
Posts: 29
Good Answers: 1
#12

Re: Bypass Protection mode on projector

07/27/2008 9:03 PM

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.

__________________
garyboyce
Register to Reply
Commentator

Join Date: Jun 2007
Location: Inverness, Florida
Posts: 87
Good Answers: 3
#13
In reply to #12

Re: Bypass Protection mode on projector

07/28/2008 4:38 PM

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.

Register to Reply
Anonymous Poster
#14

Re: Bypass Protection mode on projector

09/17/2008 7:34 AM

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

Register to Reply
Register to Reply 14 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

Andy Germany (1); Anonymous Poster (4); FKIA (1); gadgetman (1); garyboyce (1); gigaconcept.com (1); plbplb (1); Self Thinker (2); Sparkstation (1); wangito (1)

Previous in Forum: urgent: please give me the schematic for FM broadcasting station.   Next in Forum: 85 HDTV Vehicles will be put into use
You might be interested in: Projectors, Lighting Fixtures, Ballasts