| slickwillie |
| Hi, I just bought a Ampro LCD-150 projector off ebay for really cheap. The only problem is it's bulb is out. I was thinking I could manage to set up a metal halide bulb instead. The problem i have is that it won't dispaly anything probably if there's a burnt out lamp, since the "Lamp" lcd is lit up. I was wondering if anyone had an idea to fool the thing into thinking the lamp works, so I can use it. I thought that maybe I could just close the circuit, and reduce the current to that used by the buld. Anyone wanna give me some advice here? |
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| brainchild |
| Some projectors have a reset button for the lamp. |
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| slickwillie |
| If you're talking about the saftey switch that won't let it run if the cover's not on, I keep the switch pressed, but no luck. Do you guys think that the LCDs will still display without the light being on? if so, i have nothing to worry about |
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| slickwillie |
| And the unit uses a 250w MH light, so maybe I could use a regular 250w MH, but not one for projectors, and make a custom reflector and stuff, but still have it wired where the bulb is. Any thoughts? |
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| Tuga |
Hi,
I have been reading this forum for a while now, but never had the time to build anything. Although I bought the Fujinon lens and a small lcd etc to try and build a basic projector, it never happened.
Anyway, I have bought a Projector with no bulb either.
It took a while to fool it but it’s done now.
before we start..
DO NOT PUT YOUR DVM ACROSS THE IGNITOR OUTPUT. :smash: :hot: :xeye:
altough it created a nice blue arc between the meter probes...lol
You need to look for a few things:
Safety Switches:
it won’t power up if any of the covers is open.
Fans:
they might have rev control, if the projector knows they are not working it might not power up to prevent overheating or fire.
Temp sensors:
Self-explanatory.
Lamp:
Mine (Mitsubishi S120) had the lamp led flashing red.( over 1900hours gone)
After looking on the manual all I had to do was press 2 keys to reset it.
And of course, the current sensing.:
This is the tricky bit!
First I fitted a small 150W halogen bulb in the lamp compartment with the hope it would only have optical sensors…L nope!!!
So I had then to take every screw and part of the projector to open the power supply.
It’s common to use Opto Isolators or Opto couplers for current sensing on power supplies.
http://uk.farnell.com/jsp/catalog/v...?prodId=3565683
So look for these components. There will be at least 4 of them but the ones you want will be on the low voltage DC part of the PSU close to the igniters.
You should have one going active when U press “power” and the other should reply to the board once the lamp fires.
Look for 3 wires going to the psu from the main board, maybe.
All I had to do was to pull one line low and that was it…J.
The ballast, the igniter, and low DC part of the PSU ( made of 2 PCBs) aren’t even in the projector anymore.
I am sorry if it sounds complicated but English is not my native language.
I now have it working with a 15v 150W halogen bulb image is only visible with the room lights off but its ok, maybe a bit on the green side.
Hope this helps….
Any one knows how to build a 24v @ 10-15A PSU??
Or where to buy a cheap one?
Or maybe an easy and cheap way to power a 250w halogen bulb? |
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| Tuga |
I know it ‘s obvious but I better say it any way.
DO NOT connect an Halogen bulb to your projectors PSU. The Halogen bulb must powered from an exteranal power supply.
DO NOT work on the PSU with it connected to mains.
DO NOT disable any of the safety features (switches, sensors etc) built in your projector.
DO NOT TOUCH any of the mains part of the PSU even after powered off. Capacitors can still give you a violent discharge.
DO NOT try to measure the striking voltage…lol |
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| slickwillie |
Tuga: you said "All I had to do was to pull one line low and that was it"
I'm not sure what you mean here. Do you mean that all that you had to do was disconnect one cable? If I post a few pictures of my circuits, can you give me some advice? I think I've narrowed the Opto things to only a few possible ones, and you might be able to tell me which one I need to concentrate on. |
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| slickwillie |
| And will it work to just throw a 250 watt MH in, and forget all the bypassing stuff... since the original lamp is a 250 MH projector lamp, is the circuit compatable with that of a regular one? |
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| Tuga |
Hi,
I mean there was a line that was high (+5v) until the Opto pulls it low (0V).
I have removed part of the circuit that had the optos so I connected that line to 0V permanently.
You said u narrowed it down. Take the numbers on those components and make a search on Google. If it mentions opto isolators or opto decouplers you know they are the ones.
You will need basic knowledge of electronics to figure out the circuit around them, so you know to which pin should you attach what voltage.
You will need a multimeter (DVM) as well.
Take all the safety measures. |
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| Tuga |
About the “just throw a 250 watt MH in, and forget all the bypassing stuff” I have no idea.
That was going to be my next step if I couldn’t find a way to bypass it.
Now that I have a working projector I don’t feel like blowing it to bits.
I you decide to try this option remember that you are dealing with over 5000Volt pulse to ignite the lamp. You might want to try it with the lamp outside your projector….and take cover….lol.
But it might just work.
Keep me posted. |
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| mathias |
Good to hear that more people than I are trying this, also nice to hear that they use opto-couplings, that makes this thing more easy, I wondered how they know when the lamp has warmed up, but now I know that they can use opto-couplings. In my case I have a 20pin connection from the PSU so the problem is which pin do I have to pull down to 0V. The biggest problem I have is that I can´t get into the PSU without to take everything out of the projector.
As I have sad before I think this is the new DIY-video thing most people want to do in the future. Pro-projectors have all the advanced optics and electronics and better lcd:s already built in that diy-projectors can´t compete with. A pro-projector without the UHP-lamp is only worth the half of it´s price and that makes it more cheap than any other diy-projector. And the best thing with pro-projectors is that you can sell it, if you don´t want it. DIY-projectors is quite hard to sell ? |
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| Tuga |
Hi,
I had a lot of big connectors from my main board to the PSU.
But these wires were going to what was easily identifiable as the low DC regulation part of my PSU (not live).
The connector that did it for me was actually on its own, 3 little wires…lol.
If it helps look for a chip with the numbers ***494** (ex:TL494, M5T494P or equivalent)
This is a PWM chip that controls the output of the PSU. Basically I THINK this chip controls the voltage after the ignition pulse.
Somewhere around this chip you maybe able to find the 2 Optocouplers u are looking for.
I don’t think it knows if the lamp is warm or not, it only knows if the arc has been formed.
My optos were made by Sharp, PC123 chips.
As I said, the igniter and optos are no longer inside my projector so I’ll take a picture when possible.
At the moment I am looking at trying a 240v 300w linear Halogen lamp (78mm) on mine, since I can’t find an easy ( and small ) way of powering a 24v 250W halogen one.
The lamp compartment should be just big enough since it has an 80mm fan at the end.
Has anyone actually tried to use a normal compact metal halide lamp on a Pro projector with the projector’s ballast and igniter??
If any one has any ideas …... |
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| Tuga |
Hi,
Here it is as promised, a pic of the half of my projector’s PSU that is no longer used.
Inside the red circle are the 2 OptoIsolators and 1 end of the cable that connects to the main board,
Inside the yellow one is the 494 PWM chip that is supposed to control the output.
Inside the green circle is the other end of the cable and the drawing of the 3 lines ; “PowerOn”, Ground and the so important +5V that has to be pulled low.
The 2 squares on the schematics represent the “insides” of standard OPTO’s.
Hope this helps. |
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| slickwillie |
| OK, here's a pic of the PCB (sorry for the crappy quality, my camera has no macro mode, so I had to use the old magnifying glass trick). I circled the 2 chips and cable connector which I belive are responsible. I drew in a white line where the white wire connects, as the other 3 are blue. I think that the white may be power or ground. I also circled in white where there's a white dot around the pin on the circuit board, maybe this will help. Now what's your advice from here? If you need a better pic, or one of more of the board, let me know. |
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| slickwillie |
| oops, here's the pic: |
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| slickwillie |
| ok, if this doesn't show up, i'll go crazy! |
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| msx-2 |
| you are probably still under moderation , ask a moderator if you can post a pic. (maybe ace can help) |
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| Tuga |
Ok, that surely looks like it.
The fact that they are facing opposite ways (just like mine) PROBABLY means 1 is for the “PowerOn” signal and the other for the “I’m PoweredOn” return signal.
You gonna need to grab a meter and do a few things but
First:
:att'n: Do not power the Projector with the PSU opened. Lethal voltages inside. :dead:
Second:
:att'n: Read the safety warnings on my previous post.
Third:
:att'n: I take no responsibility of any damages done to your projector or to yourself.
Now we can continue, lol ;)
Draw 2 optos on a paper and try to complete the circuit around them.
Have a look at my drawing and try to compare.
1- Find out which wire is connected where exactly (the 4 of them).
2- Find out which wire is ground. This will be connected to both Optos on the same side as the connector. To do it, reconnect the wires to the main board and check for continuity between mainboard ground and the pins on the optos.
Don’t use the PSU ground since they should be different grounds. This is the main objective when using OptoISOLATORS.
Or if you have a meter that can test Diodes, with the Projet switched off, put the RED probe on the pin marked with the white dot and the BLACK probe on the other pin on the same side of the component. If it reads approx. 1V the Black is Ground.
If it reads 2.999, The RED is ground, (but I doubt this is the case)
3- Find out which one is pulled High (+5V) when you press “PowerOn” – this should be the one that connects via a small resistor (to the white dot Pin), since you can’t put 5V straight to the Opto.
You can check this on the main board side. It is easier and since you will have to power the projector to be 100% sure, it’s definitely safer to do it on the main board.
4- Find out which one is always High, (+5V) and maybe needs to be pulled low.
5 - And what is the extra wire and where does it connect to?
Once you have done this, and drawn a circuit, post it here and we can discuss the next step.
PS: Mathias have you found your OPTOS yet???? |
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| Tuga |
| OOPS! Forgot the PIC... :D |
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| msx-2 |
| someone in another topic said that on avs forum they were trying to replace a UHP lamp (=a small gap metal hallide) with a new one . By that i mean the small lamp part in a lamp module of a projector. And the price of a 120 or 150 watt lamp would be around 40 bucks. Does anyone know where i can find more information about this? |
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| Tuga |
I don’t know.
I myself would be interested on that info.
Nevertheless, I measured the voltage supplied to the half of the PSU on the pic, its approx 400vdc, soooooo….
I’ll build a 400v supply, just a simple one, with a bridge and then I’ll connect a 150w metal halide lamp to see what happens.
Its off the projector anyway so worst case I blow up a lamp worth £9…lol.
I’ll keep you posted. |
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| msx-2 |
i searched and found that it was Mathias from Sweden who wrote about uhp replacement bulbs for $40. Maybe he can post the link here.
i myself wrote this a week ago , it may be dangerous but what do you think (noone replied to it ,so i post it here again):
Problem with retrofitting projectors is that there is not enough space. However i want to try to make a cdm-t or a similar lamp smaller.
1-i was thinking some projectors use 150w metal hallide lamps, My question is :will a different metal hallide work (electrical speaking , are all 150w mh lamps compatible or does a UHP (the lamps usually used in projectors) have a lower or a higher ignition voltage?)
2- if it would work then there is no problem using the original ballast and ignitor
3-you have to get a very small metal hallide lamp to fit in the original lamp house, would it be possible to remove the outer glass from for example a hqi 150 fc2 ?(its dangerous i know, you have to do it in controlled circumstances face protection , thick leather gloves )If you look at all these lamps
http://www.andrewjjstanley.btintern...lhalidelamp.htm
you can clearly see the inner part which is seperate from the rest of the lamp, this is the part that lights up. The outer glass is probably uv protection. (and you can get that from the uv protecting glass of the original lamp house)
If you would remove the inner part (of course without breaking it) will it work? Has anyone ever tried this?
4-then there is the problem of fitting the lamp , if you have the original lamp house , you would have a reflector and all the things you need, just put your slaughtered hqi in there , and there you go 10000 hours for 30 bucks!
Am i completely stupid , or would it work?
BTW i am not responsible if you blow your eyes out or get a lot of nice glass tatoos in your face , or get a nice hairmodel after killing yourself with a electrical igniter with 50KV , in other words dont try this at home or without the right equipment |
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| Tuga |
I have plenty of space for a 80-90mm lamp on mine. The lamp compartment is 85x85 by 120mm long.
Since I have removed half of the PSU I even have room for a ballast and igniter for a 150W MH lamp, in its place; (200x75x50mm space).
I’ll try the experiment described on my previous post and if it doesn’t work what I’ll do is get a ballast, an igniter and a 150W lamp for about £50 and fit everything inside the projector.
I don’t think you want to remove any of the glass from the lamp!!! :hot: But I am only a noob. I know nothing about lamps… :xeye: |
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| mathias |
| quote: | My question is :will a different metal hallide work (electrical speaking , are all 150w mh lamps compatible or does a UHP (the lamps usually used in projectors) have a lower or a higher ignition voltage?)
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UHP and MH (HQI) lamps are very different, most UHP-projector lamps run on DC-voltage some on AC. MH-lamps always run on AC-voltage. Acoustic Resonance is an other problem MH-lamps have, they get unstable on higher frequency > 4kHz, if a UHP-lamp have this problem I don´t know so the UHP-ballast maybe use more than 4kHz AC if the UHP lamp run on AC-voltage. Most 150w MH lamps are compatible with eath others, but not with UHP.
If we remove the PSU from the projector I think there is alot of space left so we can place a 150W HM lamp in the orginalcase. I think a 150W HQI is the best choice it´s smaller than a cdm-t and it has 6000-7000K colortemp like the orginal UHP-lamp.
Here is the link to my thread: http://www.diyaudio.com/forums/show...&threadid=25918
Keep up the good work and good luck ! |
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| msx-2 |
here the question to the answer will a lamp run without the outer glass casing. It does ,this is about a mercury high pressure lamp , but they are very similar.
http://www.savel.org/hardware/uv.html
mathias> UHP and MH lamps are not that different , they are both metal halide lamps, pressures and gap lenghts are different but they are essentially the same and so they will both work on direct current (DC) i think. |
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| Tuga |
Very interesting…..cant wait to get my hands on a 150W MH lamp and try it with the original parts!!!!
PS: Slickwillie, 'r you still alive man???? |
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| slickwillie |
yup, i'm here. I'm just a little nervous and slightly overwhelmed. I'm way new to electronics like this, beisdes the very basics. I'm gonna get a drawing together probably by wednesday, since I've got no school then (yup, I'm just a kid!)
p.s. Thanks so much for all your help so far! |
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| msx-2 |
| quote: | Originally posted by Tuga
Very interesting…..cant wait to get my hands on a 150W MH lamp and try it with the original parts!!!!
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be careful if you try it , at the moment i am trying to find out what the difference is between ignition voltage and running voltage between a normal MH and a UHP , i am not sure yet , but ignition is probably 5KV for both , i havent found out how fast the drop is after ignition.(for a UHP it is around 1 second) , running voltage are maybe different, but i am not sure. If someone has some knowledge here. please |
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| Tuga |
| quote: | | I'm just a little nervous and slightly overwhelmed |
:att'n: If you’re not sure, get someone to help you.
We are dealing with lethal voltages here. :dead:
“Shaky hands” have no place near electronics…lol.
Just be careful. ;)
| quote: | | be careful if you try it |
Don’t worry I’m a qualified Electronics Test Tech….I’ll take all the precautions necessary.
My biggest problem is to get a MH lamp before the weekend. I don’t know any shop where I could just go and buy it.
I’ll have to order online.
Anyway until then I’ll just have to run my 24v 250w Halogen bulb using a 24v@27Amps PSU (650W :hot: ) that I bought from ebay for £10. :smash: lol it costs £450 new.
And I still have to make a screen somehow… :rolleyes: |
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| The Alchemist |
Man when i read this i get the shivers. My dad fixes tv's and the tube runs on 25kV I think. He always (for 23 years now, lol) warns me when i am helping him. You have to be very very very very carefull when working/measuring with more than live voltage. Please this is only for electronic profressionals, not for school kids. Also removing protecting glas from bulbs does not sound well in my ears. Come on people is your live worth less than building a projector?
So to the skilled people i say: go on. Your doing great work.
To the non skilled i say: stay away from dangerus electronics. |
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| slickwillie |
| well i see all this as a great learning experience, in electronics, and optics. As for the leathal voltage, I'm much more careful than I used to be, because about 4 months ago I was playing with the power supply for a computer monitor, and messing around with antigravity lifter things (wicked cool!). Anyway, I ended up getting a little too close and got zapped, and my arm shot straight out so fast I couldn't believe it. The feeling of being electricuted once is enough to teach me a lesson. |
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| The Alchemist |
The difference between 220 and 5000volt is large.
It will kill you.
But ok I don't want to attack you. Please be very carefull!!!! |
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| Tuga |
| quote: | | You have to be very very very very carefull when working/measuring with more than live voltage |
I totally agree with you.
That’s why in every post I warn people about it. :att'n:
Also, all my instructions are for the low voltage part of the circuit.
Still you need to be carefull since the PSU needs to be opened and there are :att'n: high voltages inside even after switched OFF. :att'n:
It does worry me that someone might get hurt or killed trying to save a couple of hundred £ ... :(
Everyone please, If you are not sure what you are do’n ..Then DON’T do it!!!
Ask for someone’s help.
I have to do it some times and I’m a qualified professional. |
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| bobharry |
I have to agree too, and I think that before you try something new it should be approved by an electrician.
Tuga:
How do we discharge psu's and check if they are discharged? |
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| mathias |
About using the built in UHP ballast to metal halide lamps:
Here is a good link to all about discharge lamps, I think I have posted it before: http://members.misty.com/don/dschlamp.html
As I have sad before most UHP-lamps run on DC-voltages and mh-lamps don´t. From the link above:
"Metal halide and sodium lamps should not get DC. Use these only with ballasts that give the bulb AC. In metal halide lamps, ions from the molten halide salts can leach into hot quartz in the presence of a DC electric field. This can cause strains in the quartz arc tube. At the ends of the arc tube, electrolysis may occur, releasing chemically reactive halide salt components that can damage the arc tube or the electrodes. The arc tube may crack as a result."
Mh and HQI have a ignition voltage 3000-4000kV, UHP have 5000kV.
Here is an other link how HID lamps works: http://www.ballastdesign.com/overview.html
So I think the best and safest is to try to disconnect the built in ballast, and use a external mh-ballast to the 150W mh lamp. |
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| mathias |
| Here is an example of what happens when you run a HQI/cdm-t lamp on a high frequence HPS-ballast, the inner arc-tube is cracked and I´m glad that it didn´t explode ! So be careful and use only right ballast to right lamp. |
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| Tuga |
Hi,
Thanks Mathias!!
I have found that my projector uses a DC lamp.
This more likely than not means that a MH lamp will NOT work with the original Ballast/PSU.
I will not try it since I think it will be a waste of a good lamp.
So I will be ordering a 150W ballast, an ignitor and a 150W HQI lamp instead for around £60 the lot. Unless someone knows where I can get it cheaper in the UK... |
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| bobharry |
| You could give www.internationallamps.co.uk a try, I still have to check the price on the 150w cdm-t bulb, but the prewired ballast capacitor and ignitor is only £25.45, and the holder is only £3.49, prices excluding VAT, and delivery is £2.49 |
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| Andres |
TUGA, ARE YOU THERE??!?!
I've followed this thread to the extent of my posibilities. I could use some help now.
I've found the optos, and identified one cable as ground but, when measuring voltage between this "ground" and the ground marked at the mainboard (see pic. 4) I get 5V....I'm confused.
All voltages are the same at Standby, Startup (when I press the power button) and after the Lamp Led starts flashing (signaling it has detected no lamp).
HELP!!!!
Andres |
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| Andres |
I dont know if I got this right... could it be that I have to pull line 2 (in my diagram) to 5V? This seems to be the return line, right?
If anyone knows please reply, otherwise I'm gonna have to try anyways and I dont feel like blowing any parts of my projector up.
Thanks. |
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| Andres |
I DID IT!!!! THAT WAS IT!!
I now have a fully functional projector with no lamp!!
Step 2: getting a HQI lamp in there. |
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| slickwillie |
Sweet! I totally forgot about this thread, and my projector is still apart on the floor. I gave up on it months ago, but now it looks like i can finally use it.
Now how do I pull that line to 5v? |
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| Andres |
If you look at my pictures, they look very much like yours but the optocouplers are switched I think. The one you are looking for (the one that tells the mainboard when the lamp is on) is the bottom one, or the right one if you are looking from the connector.
You need to bypass that optocupler. Look at the drawing. If you do that, that circuit is ALWAYS going to be closed and so the mainboard will get the "OK" signal all the time.
I used a paper clip on the connector to do this. You have to be certain which wire from the connector goes to which of the four "ends" of the optocouplers to do this.
Ask again if its not clear enough. |
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| Tuga |
Hi,
Sorry for not replying but was away on a fishing trip.
I'm glad that the info on using optos was useful to someone else!!
Well done! now you only need to build a light engine small enough to fit in the projector.
I still don’t have the lamp. :whazzat:
You might find that you can remove some bits out of the power supply side.
In my case a whole PCB, it will give me room to fit the ballast and ignitor inside the projector. Once is finished you wont be able to see the difference from the outside. Hopefully. :D
:att'n: but be careful with the HIGH VOLTAGES. :att'n:
Always work on it switched off.
Also remember that capacitors can store enough to give you a nasty electric shock even several hours after you have switched the power off. :hot:
:att'n: |
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| Andres |
Hi Tuga,
Following what you had done I also removed the whole PCB with the optos with great success!!
If I remove a steel box (with a glass window) where the lamp used to be I now have a space thats roughly 5"x5" by 7" deep. I hope this is enough for the lamp at least. I might not mind putting the ballast on the outside.
I've been looking into the light engine situation for a few days and I havent been able to figure out if I can get a lamp+reflector thats gonna give me a beam thats parallel enough. I might need to add a condenser lens to the setup, which will increase the size of the light engine.
What are your thoughts on this? |
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| Tuga |
Hi,
That I would also like to know….lol.
I tried with a dichroic halogen bulb 250w with a external PSU (to big about 600W)
And the picture was acceptable, but I had a IR filter right next to it and the bulb didn’t like it and died after 10mins...
I will try fitting an Osram HQI-T (85mm long) to a par20 reflector and see how it goes.
I have not tried any optics or light engine set up yet so I am not the best person to ask.
I think the ones who can help you /me on this are, Mathias, Ace and Tiarb. (no disrespect to all other great minds on this forum)
Tiarb as done it and tried a few options so make a search for posts from Tiarb.
There is really useful info on them about retrofitting.
I still have to wait a few weeks before I can order the da** lamp.
Please let us know how it goes…
PS: Slickwillie, U don’t know how RELIEVED I am to ear from you again….lol :cheerful: |
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| auz_mo |
I have a light, a ballast and a socket for sale, its a brand new 400 Watt Metal Halide bulb, socket and ballast, I have an extra one from a project I was going to try with two bulbs, its never even been used, BRAND NEW!
I still have the reciept for it all at 182.34 CDN, its all high quality low-noise stuff, I want 150.00 CDN for it all, make me an offer if you don't think thats reasonable.
Let Me know at this email address: j_osborne@unitz.ca
Thanks. |
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| Andres |
| The company is going to receive those products next week, so they wont have a price until then. I hate waiting. Patience is a virtue I wish I could buy somewhere. :-) |
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| Tiarb |
They are very likely very very expensive products.... 4 example osrams 150w HQI-R bulbs (similar to those that were behind the links, MH's with built in reflectors) WITHOUT ballast/electronics.... 180 euros....
Regards
Ti-Arb |
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| Bruwed |
To answer some the questions that have apperaed on this forum and give my bit of info:
Firstly, the reason that the MH and UHP lamps have a small electrode gap is so that the light can be spread evenly by the lamp reflector over the required area. All that does is provide an almost parrallel light source through the rest of the optics to the LCD screens.
So there is nothing magic in using a point light source and no reason why any other light source cannot be used.
The difficulty is obtaining an even light spread of a constant light temperature.
Secondly, I have been using street light MH inner lamps in one of my projectors for several years now. These are quite cheap to purchase and have an expected life of 10000 hours, but, they do have their own problems. Most are AC types and so the electrodes are equal in size.. If you are going to use them on DC then you will have two problems - one, one electrode will overheat - two, there will be problems with chemical reations at the hot electrode. I f your projector has a DC supply for the lamp, it is better to obtain the DC types in which one electrode is much larger than the other.
For every one that I have tried, I have carefully broken the large outer glass cover and removed the inner quartz bulb. Using linen gloves to handle it, I have then glued it in place in the glass reflector of an old projector lamp, using muffler cement. The correct location to give a fairly even light output can be seen from the front by looking at the image in the reflector surface. It must be evenly looking at the electrode gap.
There will probably be some extra leakage light from the rear of the centre of the lamp holder so make sure that you use enough muffler cement back there to block this.
Now without the outer protective glass envelope the lamp will output a lot of UV. So be careful and do not look at any leakage light when it is use. Also make sure that you UV filter between the lamp and the LCD screens is in good condition. Otherwise you LCD screens will gradually deteriorate.
Thirdly, regarding the ballasts for the lamps: all have current limiting device in them since all of these HID lamps are inherently negative resistance types. SO you will not overload the ballast from a current point of view. But, and this is important, different types of thes lamps have different gases in them ans os the operating voltage for the arc will be different. This is where you can overload you ballast. If the normal lamp draws 4 Amps at 30 Volts across the lamp then that is what the ballast has been designed to accomodate. But if the replacement lamp has more or less voltage across the arc when running then you can either overload the lamp or the ballast.
In addition, the high voltage need to get the lamp to start arcing in the first place will depend on the gases used as well as the electrode construction. Some lamps will not strike because this voltage is too low. Now many street lamps have an extra electrode to asssit in lowing this striking voltage. Some even had then externally wrapped around the unner bulb near to the opposite electrode.
So you have to be very careful in changing the type of lamp. But it can be done.
Forthly, the actual light output that you will get on screen will probably be a bit less than the equivalent normal lamp. This is due to the difficulty in aligning the new lamp to give full light output. There are a lot of losses along the way for older projectors wheras the later types have btter optics. In all cases though LCD screens tend to lose about half the light from the lamp.
Finally, for all those people trying to use LEDs, keep going and do not pay any attention to the negative people. I too have tried using LEDs - 100 of each of red, blue, and green - but have not had much success. The distribution of the light was too uneven and the colour temperature was not only uneven but also variable from one day to the next, even with current control to each group of colour LEDs. The light output was not as high as it needed to be and only produced an apparent light output of less than half of the normal brightness of the normal 1000 lumen lamp.
I suspect that the heat from the very closely matrixed LEDs was affecting the output of the individual LEDS. For reference they were obtained from Hong Kong via eBay and the red LEDs were advertised as "typically 20,000mcd" output. |
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| Tuga |
I'm trying to start a new thread but get the message:
"please search the forum before posting"
and wont let me start the thread anyone knows what's happening?
By the way, how do you post more than 1 pic in the same post?
Teo |
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| shlomid |
Thanks Thanks Thanks Thanks
Thank you Tuga you are the best!
:D :eek: :eek: :eek: :) :) :) :) :) |
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| anthp |
I want to use this lamp for a dlp projector I think with the colour wheel I could get problems with interfererance with 50hz like a raster line if I use a transformer type balast. I think a high frequency or DC is needed the balast in the picture looks like a high frequency switch mode supply i think this should be ok
of course I could be totaly wrong
any ideas on this would be good |
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| jamesbeat |
hi, i have been reading this thread with great interest. i am trying to replace my projector's lamp with a cheaper one.
i thought i had worked it out, then it turns out that some (all?) projectors use uhp lamps which are dc as opposed to ac for mh!
i have two projectors which i bought off ebay very cheap- a liesegang dv290 and a 3m mp8640. they are actually the same projector marketed by the two different companies (the hitachi cp-l850w is also the same)
i bought the liesegang partly because it was cheap, and partly because it is old and big, reasoning that the older and bigger it is, the more chance i have of retrofitting the lamp successfully.
i got the 3m because it was dirt cheap (won't power up) and because if i manage to work out a lamp arrangement that works, i can just duplicate it on the other machine (cinema in the bedroom too!)
anyhoo, the user manual for these machines states that the lamp is 260w metal halide- does this mean that the lamp is definately NOT a uhp lamp, or are uhp's a type of metal halide?
i'm guessing that it's a normal metal halide lamp, as it's an old machine (presuming uhp's are the latest technology). when i take the lamp out of the reflector, i'll be able to get a good look at the electrodes- i believe they are different sizes for dc (uhp) and the same size for ac (mh) is this correct?
as far as i know, mh lamps need their rated current +/- 10%. if this is correct, a 250w lamp powered by a 260w ballast should be fine.
could anyone who knows about these things check the above and tell me if i have made any mistakes before i blow my lamp/ projector/ self up?
if i get this to work, i'll write a nice detailed description of exactly what i did and how i did it, as i can't seem to find any posts from people who have done this |
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| jamesbeat |
by the way bruwed, thanks for the above post, it was the most useful one i have managed to find on this subject.
sorry, but i'm new at this (although i do have some electronics experience) so i'm still unsure about a couple of things:
how do i tell what voltage and startup requirements i need, and how do i find a lamp with the same specs? all the lamps i have found on the net in the uk tend to be from aquatics or 'herbal' growing companies and they don't list specs, just classify them by wattage. could this be because all ballasts used by these folks are the same type?
i have even seen electronic ballasts that the vendor claims will run ANY mh lamp of the right wattage.
all the literature i have found seems to say that any ballast will run any lamp as long as the wattage and strike method are the same- they never mention the voltage.
i don't mean to contradict you- what you say about voltage makes perfect sense- i just don't know how to go about buying the right lamp if the vendors don't supply this info.
the only thing i can think of is that if a certain gas needs a certain strike method, buying a lamp that matches the strike method automatically means the voltage is correct too?
when you want to replace a lamp that you have already modified, how easy is it to pick out the muffler cement? i like this idea because i had been trying to work out how i'd attatch the lamp, yet make it removable when another replacement was necessary.
by the way, if anyone from the uk is reading this and wants to try something similar, muffler cement is called 'exhaust putty' here.
i would really like to use the original ballast if at all possible, but if not i believe i have found out how to trick the pj into thinking the bulb's ok (i have the service manual:) )
bruwed has done most of the work- (and appears to be the only person who has had the courage to remove the arc tube from a mh lamp!)- if we work on this we could get a tutorial together so other people can retrofit their commercial projectors. there certainly seems to be a lot of demand for this.
with the dirt cheap prices of lcd projectors on ebay with burnt out lamps, this could be the best thing to happen to diy projectors ever!
i don't mean to belittle the efforts of all the diyers here, but not everyone has the time, cash, technical ability, or room for a diy pj
i think that some people go the diy route because they want a cheap functional projector, not because they enjoy the challenge.
my reason for wanting to learn how to relamp old pj's is because, although i could afford to buy the proper lamps, i resent the artificially inflated price (and i want to feel smug:D)
also, if i do this, my friends will take the plunge and buy an ebay bargain- then we will all have home cinema! |
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| pattycakes |
tuga,
what ever happened to your mitsubishi s120?
i am waiting for my telex p1000 to arive in the mail ( broken bulb) from what i understand these are the same exact projector.
did you just use a different bulb with the current projector and psu or did you do soemthing else. all \ any details about your s120 would be much appreciated |
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| carozoynarizota |
| quote: | Originally posted by Tuga
I now have it working with a 15v 150W halogen bulb image is only visible with the room lights off but its ok, maybe a bit on the green side. |
Tuga I have some questions about it.
S120 uses a 150W MH Lamp, according to what I know they had an efficiency rate above 80%. Thus mean only 30W are dropped due to heat conversion.
An halogen lamp have an efficiency of aprox. 20%, so you will have in this case 120W that are converted to heat instead of light.
Have you done something to avoid increasing temps inside the equipmen for using this new lamp??
The other question is about how bright it is the image. A MH may have half the luminosity at the end of its life. That means that a 150W (120W whithout the 30W from the loss) may behave as a 60W one. But the halogen starts giving us only 30W out of 150W, thas half the MH a the end of its life. Is it still usable the S120 in that condition??? |
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| supersan |
hi,
just regd. to say a hearty thanks to tuga for providing such valuable info about this circuit.
I own a Kodak DP1050 and I was successfully able to isolate the opto-isolator and now the projector is running without a lamp.. all i had to do was short-circuit the red and the middle wire and now it runs on its own.
so now i've joined the looking for a replacement lamp club.. if anyone has any ideas on what works best please reply to this thread..
again thanks a million for all the diags and insights. |
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| fettt |
Hi all! this is a old tread , but i need your help.
I just purchased a 3m projector without lamp. This doesnt turn on.
I can send some picture , or if someone can guide me how to!
Thx alot! |
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| atoz |
Hello, I am new to the forums. I have just purchased an Infocus LP690 from ebay. I am dealing with similar issues, and have the same 3-wire connector from the igniter board to mainboard. However, I have 3 opto sensors next to this connection.
Tuga notes:| quote: | | As I said, the igniter and optos are no longer inside my projector so I’ll take a picture when possible. |
Based on this, if I figure out what the otpos are doing, and which of the 3 wires are 5v can I remove the entire igniter? If this is correct, what do I do with that 5v line? |
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| atoz |
| Okay so I got impatient and went for it. Probubly not the smartest thing, but it worked. I made a jumper cable and connected the ground and +5v going into the mainboard. Projector came on as expected, now its time to find a suitable lamp. |
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| SuperDre |
Well, maybe a new player in town with a good replacement (only the size of the ****** would be a problem for most beamers I guess (17.3cm x 13.5cm x 9.1cm):
(www.luxim.com)
http://www.lifi.com/dynamic/display.php/36
It's already being used in Panasonic RPTV's.. I just haven't been able to find a price for the unit.. |
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