Panasonic PT-L595U Retrofit

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Hey guys, new here so please take it easy...

I have a read a bit and thought of building from the ground up but decided against it. So here is my situation.
I bought a Panasonic PT-L595U projector for about 80 bucks on Ebay knowing damn well I might be throwing it out shortly. Since recieving it the lamp is shot and I the initial (what I bielive was a UV filter) is busted.

First off UV filter, to confirm if I hold this square piece of glass to the light and move it around the reflected light is violet and the passed through light is green at a 45 to the source. If someone could confirm this is only a UV filter I would appreciate it.

Second busted lamp. Well I will not be spending $500.00 to replace it only to find out the LCD's are no good. So reading the specs I have found out it is a 280W DC MH lamp, I have finished dissambling the dichroic lense assembly away from the actual lamp and saved it for future use. Now I work at a major electrical distributor and lamps from any of the majors is no problem for me to obtain.
Lamp problem one. I deal with lamps everyday and I have never seen DC refered to in a metal halide as it usally stands for double contact bayonette socket, but in this refrence it is refering to DC power. So a litlle concerned this was some special lamp I looked into MH ballasts and driving the lamps with Direct Current. I discovered all electronic MH ballasts used DC and it actually prevents flickering and extends lamp life. So all MH lamps will run on DC something I didn't previously know.
So knowing this I decided to test my projector with some longer leads running to a standard 250W Mogol base lamp. (looked kind of funny) Well what do you know first shot bang up and running. I ran it forr a few minutes a little nervous because the unit had a blown fuse I replaced with tin foil (I know stupid) so I wasnt sure if it was drawing to much current I would have no protection but a decent gamble as that is what a ballast does limit current.)
This is when I learned lesson two abhout these liitle projector lamps and there electronic DC ballasts. I had noticed in the lamp litreaure it refrencing hot restrike with a yes or no column, now I know why. You see MH lamps when hot are a ***** to restart unless you use a couple of spikes of High Voltage to jolt them back into exitement. My standard industrial 250W didn't like this much. So as long as the lamp is cool it should start first shot but don't try to restrike while hot.
So my questions are as follows does anyone know how to disable this hot restrike high voltage module on the ballast? Does anyone know if an HQI lamp can handle such abuse? Thirdly has anyone been sucessfull with this sort of retrofit?

My plans are to bust the end off an HQI (just the porcylin socket and re-insert back into the dichroic reflecter, try to center and affix the way it was. Does anyone know the smallest Arc Tube HQI in the 250w range?

I am sorry if this rambles but I think what I am trying is possible and feasible just need a small not so pricy HQI, some lamp cement (Have to call the boys at Osram to ask what to use) and a little patience.

Any input would be apreciated..
 
greidy78, there was a post ages ago from a guy who retrofitted a sony LCD projector with regular Halogen 150w bulbs, so (if what I believe you wish to do is to replace the bulb with an inexpensive bulb) it is possible. The biggest problem is to 'trick' the projector into thinking that the original bulb is still inserted and is still working, so the projector will function correctly. As I seem to remember it was a case of shorting out a resistor, but it may be different for your projector, guess it's a case of looking at the circuits. The other problem is that projectors have built in compensation for changes in lamp output, e.g. when the lamp is new the projector recognises this and increases the contrast electronically and decrease the brightness of the individual tft panels accordingly, and when the bulb is getting old, they reduce the contrast and increase the amount of light than can pass through the panes ( I hope that is clear-ish....basically the projector compensates for changes in brightness of bulbs over their life span...) But I doubt that would in reality be a problem for you, assuming you can trick the projector into thinking the original bulb is still there/working.

As for the filter, if there is a greenish colour than it sounds like that is def a UV coating on it.

As for retrofitting a bulb into the projector using the same ballast, my understanding (any one feel free to correct me!) is that ignition voltage varies considerably among 'original bulbs' used in LCD projectors, so I would guess you would not be able to use another MH bulb without modifying the ballast.

As for $500.00 for a bulb, are you sure it is that much, I know most shops quote huge prices for a replacement bulbs as they don't ,make much money on projectors so they think they can get away with charging stupid prices for bulbs, but that does seem a little excess, I know here in the uk, when it comes to bulb prices, you can usually haggle them down considerably, e.g. at least 50%! The problem with bulbs/projectors is that in reality most projectors in commercial environments brake/become obsolete and are replaced long before the bulb goes, e.g. for example at many universities the projectors is usually replaced a long time before the bulb goes so demand for bulbs is actually quite small and if treated well, e.g. the air filter is replaced regularly and the projector used for a good period of time, e.g. 1/2 and hour at a minimum the bulbs usually do last a lot longer than the stated rated life!

Sorry iv'e ranted on a little long, but it is possible to use a different bulb in a LCD projector assuming you can trick it into thinking the original is still there and working, I will have a search on the internet for a link to the person who converted his sony projector that I have in mind....


Hope this post helps a little......

My sugestion would be to work out how to trick the projector into thinking the bulb is still there/working and replace the bulb with say a 250w halogen with a cold mirror or a 250w MH bulb with a seperate ballast.
 
First off UV filter, to confirm if I hold this square piece of glass to the light and move it around the reflected light is violet and the passed through light is green at a 45 to the source. If someone could confirm this is only a UV filter I would appreciate it.

Hello greidy78

The projector you own is a 3 LCD type. That piece of glass is probably one of the dichroic filters which passes green and reflects the remaining light on to another dichroic filter to separate the remaining two primary colours.

have a look here
http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productID=2433

hope this helps
DJ
 
Thanks guys for the posts!

With the help of DiyLabs I was able to trick the projector and power up as usual.

As for using the internal ballast I have decided against that.

I have been sucessfull in retrofitting with a 70W T6 Lamp and a somewhat awkward reflector assembly. But it worked all be it dimmly. But at least I was able to test the LCD's and everything looks to be ok.

The lens is in fact a UV filter and I have found a suitable replacement (in fact about 200 of them have been sitting under my desk at work for over a year).

All that is left now is to put in a 250W HQI and properly design a reflector for it.

Thanks Again
 
Blue filter replacement / philips LC441

As for the filter, if there is a greenish colour than it sounds like that is def a UV coating on it.
I have been given an LCD projector (Philips LC4441 with about 30 hours of usage only) that has a defective filter which makes the picture unwatchable (big area with yellowish to blueish wrong colours).
I have opened it and seen (from above) that the blue filter is distorted, maybe by heat (as opposed to the green and red filters which seem completely flat).
Does anyone know how to replace a filter on this model without damaging the light unit and where to find the filter ?
Thanks in advance.
 
marceljack, try this firm:


http://www.knightoptical.co.uk/


they will probably have the filter you require, if not they will either make you one or tell you where you can get hold of one or have one which will be very similar.

can you give any more details as to the size, thickness, or any pictures? Maybe we could help then. My guess it's it's just a band reflecting dichroic filter. Is it at 45 degrees to the light path so blue light is reflected by it at 45 degrees?


something like:

item numbers:
FDB4754025

or
DB4904025

on the following page:


http://www.knightoptical.co.uk/acatalog/FiltersDichroicbeamsplitters45Short-wavereflecting.htm


maybe, but without further details or maybe a picture or two it's impossible to help further.


Can you give us any more details?


James.
 
LC4441 filter

Thanks jrhilton for your prompt help.
The filter in question is not a reflective filter but a transmitting filter on the light path just in front of the blue LCD.

There are of course 3 LCDs forming 3 sides of a square seen from above (after having removed the main electronics board).
With the lens "north", the green LCD is at south, the red is east and the blue west.

The filter seems orange in colour.
My first problem is to find how to remove the distorted filter without damaging anything in the optical unit, since I don't have the service manual.

Thnaks again !
 
trying to retrofit PT-L595U lamp

I have recently acquired a Panasonic PT-L595U LCD Projector with a blown lamp. The start of this thread was about retrofitting one of these projectors with a cheaper metal halide bulb and I would like to attempt to do this.

Could anyone help me out with attempting to trick the circuitry into thinking the correct bulb is there and working? I know it's possible, I just have to figure it out.

Also, there is a glass plate that seems to be shielding the light cavity from the rest of the projector that has a crack in it. Is this a polarizing plate, a UV shield, or just a heat shield? Will the crack have a large effect on the output of the projector?

Any help would be greatly appreciated.

Thank you in advance!
 
Metal Halide Bulb

I have managed to figure out how to trick the electronics on my PT-L595U into thinking the original bulb is there and can get the LCD to come on. For the time being I'm not going to worry about the cracked glass plate, if it becomes an issue I'll be back with more questions.

Now I'm trying to find small metal halide bulbs (250W). All of the bulbs I have found are around 8 inches long. Are there any distributors that sell metal halide bulbs that are around 2 inches long?

Thanks.
 
Interestingly enough, I just acquired one of these projectors as well, though mine is branded as a Polaroid Polaview 211E (same projector, different name).

Mine also has a blown bulb, so I'm wondering: How did you trick it into running without the bulb, mobius? I'd like to try my hand at replacing the bulb with something else too :)
 
Tricking the projector

After taking the cover and front panel off, you will see two sets of wires running to the ballast for the bulb. The larger set is power, the smaller set is for control signals. There are three wires (5 volts, ground, and signal). I believe that the signal line is held at 5 volts with respect to the signal ground until the the bulb ignites, after that the signal line goes low. All I did was short the signal line to ground and the projector fired up and I could see the LCD come on (I shined a flashlight into the projector and looked in the lens). I'm not sure how safe shorting the signal line is for the control electronics in the long term, but that is how I did it.

Good Luck!
 
Re: Tricking the projector

mobius13 said:
After taking the cover and front panel off, you will see two sets of wires running to the ballast for the bulb. The larger set is power, the smaller set is for control signals. There are three wires (5 volts, ground, and signal). I believe that the signal line is held at 5 volts with respect to the signal ground until the the bulb ignites, after that the signal line goes low. All I did was short the signal line to ground and the projector fired up and I could see the LCD come on (I shined a flashlight into the projector and looked in the lens). I'm not sure how safe shorting the signal line is for the control electronics in the long term, but that is how I did it.

Good Luck!

Good news over here! I managed to get it working following your instructions. Took a small piece of wire and shorted the pins on the end of the 3-pin cable itself, then taped it with electric tape so nothing else would short. Turned it on, and 5 seconds later it's happily running as though it had a bulb. :D

I'll try to get some photos taken soon to show everyone, but it might be a couple days -- I've got a fairly full schedule tomorrow.

By the way, mobius13, how is your retrofit project coming along? What kind of bulbs are you using/going to use?
 
Sorry I haven't been around, everybody. College has been keeping me busy... But, that hasn't kept me from working on the projector. After I got the pin shorted out and tricked it into running with no bulb, I went ahead and looked into replacement bulbs.

Since I don't really have much money right now, I decided to go for a simple Halogen setup, keeping the original reflector and bulb cage. After looking for a while I decided on an EYB Bulb and socket (GY5.3 socket, if anyone is curious), because it would fit inside the original reflector and would be relatively inexpensive to maintain (also I was nervous about putting too powerful a halogen in this thing, knowing Halogens run hotter than Metal Halides...).

So after a bit of thinking, a spare PCI slot bracket, a dremel, electrical components, and a few hours of free time, I now have a fully working retrofitted projector!

I hooked my xbox up to it and I've been watching videos in Xbox Media Center and playing games for the past few days now. :D

It's not quite as bright as I had hoped for, and the color/contrast is a *little* off (probably due to the bulb being a halogen and the projector not being adjusted for this particular bulb) but for now I have 60 inches of picture for a total cost of $25 plus time! :)

I'll try to post pictures sometime this week so everyone can see what I did! :)

If anyone is curious about how to use these 82 volt halogens, you basically use a diode in series with the bulb to chop off half the AC waveform, which results in the voltage these guys are looking for. Of course this requires a pretty big diode, so I grabbed a large bridge rectifier from my local radioshack and only used 2 legs. I'm getting power to it through a computer power jack I grabbed out of an old power supply, and re-wired the old bulb cage power input connector to give out 120 volts. Everything is working fine so far!
 
First off, sorry for bumping such an old post, but I couldn't PM/email the people in this thread that could answer my question since I don't have enough posts yet.

Anyways, Day2230: would you mind posting those pictures or a more detailed list of instructions on getting the halogen bulb to work? I have the exact same projector and it's got a blown bulb. I shorted the 3-pin cable and the LCD comes on and works just fine. I'm a second year EE student, so I'm not a layman, but I don't know much about bulbs or projectors. So if you could post some details on how you adapted your halogen bulb to run in this projector, I would be most appreciative. I'm mostly worried about getting the old bulb out without destroying the harness, as well as electrocuting myself.

Thanks in advance!
 
Sorry everybody... I've been busy with classes and work and completely forgot about posting the pictures... I'll see if I can snap some pics of what I did in the next few days and get something uploaded.

The projector still works, though I switched over to an ENX halogen bulb after my first EYB died. The main reason was the hassle involved -- I ended up damaging my second bulb while inserting it into the reflector and decided I would try out a bulb with a built-in reflector. I was happy to find out that the screen was still decently lit even with the smaller diameter of the ENX's reflector.

What I did to run the Halogen in the projector was pretty basic, and could probably be improved upon. I cut the wires running from the MH ballast to the bulb cage, and re-routed the bulb cage connector to a 120V AC jack and switch I mounted to the side of the projector next to the bulb cage. I then hooked up the halogen bulb in series with a large diode (I used two legs of a bridge rectifier since that's what I had sitting around) inside the bulb cage in place of the old bulb and ran wires from that setup to the bulb cage connector.

I'd suggest heat-sinking the diode and using high temperature RTV silicone instead of electric tape because of the temperatures near the halogen.

In the future I'd like to use the logic signal that controlled the MH ballast to switch the halogen bulb, and hook into the main power connection to the projector instead of adding my own power jack and switch, but for now I'm happy with a working projector :)

Next up: Building/buying a component to VGA adapter so I can use my xbox in progressive scan mode! The composite video scaling/deinterlacing on this projector is a little bit icky sometimes... it seems like it just grabs 2 or 3 lines and uses them as the next few lines, leaving a sort of ripply effect in the picture. Also the color adjustment in composite video mode leaves a bit to be desired.

I'll try and get some photos soon though, everyone.
 
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