Guys I'm kind of inexperienced with the metal halide bulbs, and its equipments. I have an ALLY PTV-01B projector. It uses Osram 150 watt mh. bulb. And I want to change it with Osram 250 watt mh. bulb.

I just realized that, those bulbs use different sockets. However there is no big difference with the dimensions. 150 watt one is: 132 mm. 250 watt one is: 163 mm.

So I guess I could easily increase the space of two holders (please check over the picture).




Do you think; could ALLY's ballast/power supply, etc. handle 250 watt bulb ? If it can handle 250 watt; then I will start the operation. Please enlighten me quickly .

You have a few issues that may stop you from doing this:

1) You will have 100W of extra heat generated within your box. You will need enough ventilation to remove the extra heat.

2) You may lose your bulb focal area and you may have to move the bulb forward or backward to get the optimum location. The extra movement may place the bulb too close to other components/box and create a fire hazzard.

3) The ballasts are usually made for specific wattage. You may have to get another ballast.

Thx for the reply.

1) Actually heat will not be an issue imo. I assume even default fans can handle extra 100W (if they can't, I could add one more 80 mm fan, there is some room).

2) There is some space at the back side of light box, but there is no space at the front .

3) I will post some information about its ballast. Please wait .

Ok ! Here is the ballast ;

I can seem to be able to find specs for that ballast. It seems to be a D250 model from an unknown company. Google doesn't bring anything up that I could find.

The 250 might mean 250W but is could also mean 250V. What is your power source: 110 or 220Volts?

At the bottom left of the ballast it shows C 20uF/250???. What is after the 250?

Actually I took that picture two days ago, but I will open its case next day again (I will take all the information on it).



My power source is 220V. And I think that ballast is for 250W bulbs , because there is another sign for voltage (2.15A 220V) .

P.S. : I couldn't find any information on Google too (with D250 input).

If you put a 250 watt lamp in the 150 socket it will still make around 150 watts because the ballast is made to make 2.1amps.(It says on the side) you could increase the size of the cap from 20 to 25uf and the ballast will make more power.( you may need to add a fan on the ballast)
The safest way is just to pick up a 250watt HQI ballast from eBay they are all over just make sure it has a 220v input tap. I would up the fan too

If you chance the cap make sure it's says 250VAC on it (procted)

Thx for the information. I will post the whole ballast info. I think I will do this mod, because ansi lumen level is really poor to me. BTW, I heard that they have also overclocked (?) the ballast. I mean the bulb is probably not working at 150W, it should be working around ~200W. (I seen this info in this forum.)


P.S.: I'm quite sure, that Brainchild has all the secret information about this projector (ballast info, capacity etc.).

I'm verrry happy , because the ballast is for 250W bulbs (you can see it on picture #2) ! Strange thing is : Why they use 150W bulb with 250W ballast ? (Typical commercial strategy ?) With this tricky combination; they probably overdriven the lamp (150W to ~200W). And this trick also reduces the bulb life to 6000-8000 hours (original bulb life should be ~12000 hours). (Some members was also figured out this tricky situation.)

BTW, default ignitor (OSRAM CD-7H) can run 70W-400W metal halide bulbs.

I took the pictures of all the electrical parts;



You can easily see that 250W sign;


This must be ignitor ;


But what is this (fuse?) ;


I did a research with "2501A" input (which is catalog number of the ballast), and found some info;


So; if I buy a 250W metal halide bulb (with socket components), can I put it directly ? Will it work properly without any modification ?


P.S.: Don't worry about heat, and focal area calibration issue. I'm hoping that I could handle these issues.

With that last information you found I would feel comfortable that your ballast will handle a 250W MH bulb.

Have fun with your mods!

Thanks mate for your help, and interest ! I feel better now. I hope I could post some screen shots after this mod.

Nope, capacitor
Can you tell us what the value to the left of +-5% is?
This part determines to some extent how much current is going through the lamp. According to the table, it should be 20uF for a 250watter.

It would be interesting to see if they tweaked that to account for the lower wattage bulb...

edit: misread table

I was almost closing the case... And I seen your post. I have checked; its value is "20uF".

Wow, really does look like they're overdriving that lamp
There must be a reason...

What do the whites look like? If you display a white screen, does it look "white" white, or a bit yellowy, or a bit bluey? (compared to an lcd monitor for example)

Actually I'm not happy with the white. It looks like a little bit yellowy (I can say that its temperature is about 3750-4000K).

The list showes that for a 250 watt lamp the ballast runs a 32uf cap so if you want 250 watts then you will have to change the cap to 32ud. you could also just add 12uf as long as the cap says 12uf 250VAC on the side you will be OK. A DC cam does not say VAC on the side so make sure you look.

I have done a lot of testing on overdriving the ballast. One thing is if you overdrive the the lamp the color temp will lower. If you have a slight yellow screen it will look better if you don't over drive the lamp and the lamp life will be a lot longer.

I'm sure they over drive the lamp just to shorten the life so they can sell more lamps at a huge markup.

I'm kind of uneducated with the electrical things, but there is two model/line for 250W ballast on the table. I mean "20uF" should be able to run 250W bulb (because mine is also in the 250W ballast section), isn't it ? So I'm confused. Edit: I think I just understood that "why I should be changing the cap" (due to my poor English, my understanding is a little bit slow lol).

BTW I've looked "VAC" sign section again, and I can confirm that it is "250 VAC".

Yeah, I misread the table
If your ballast is the 2501A, then its designed to run a 250W lamp at 130V with a 20uF cap

That may be a problem in that the lamps I know of (eg HQI) run at 100V....
Seems worth giving it a shot anyway

Edit: I've got it. It's just like cpu overclocking. If lamp works at 100V, my ballast will overclock its voltage (to 130V), and will decrease its amperage (to 2.15A). However I will get ~250W output (just like 100V ballast model). Other ballast also gives same result, via lower voltage and higher amperage.

My setup will be more like fsb overclocking for 250W / 100V bulb .

You will need to know the lamp voltage of your new 250 watt lamp. It should be 100v so power = voltage x current.

If the lamp has is 130v /250 watt lamp you will not have do anything just pug it in. If it is a 100v/250 watt then you will need to chang the cap.

I would gess that the old lamp was 100v so the ballast will not make 250watts with the 20uf cap. it won't make 250 watt with the new one either.

If the new lamp is 130v I bet it will have a longer arc too. A lot longer. You might try to find one with a 100v rating.( I have never seen a HQI with a 130v lamp)

If you add a 12uf 250VAC cap you could use a swich for a high low setting. You should read the thread "overclocking lamps and ballast"

If you look at the chart it list the vaules are wrong but right.??

They list for the 130 volt lamp
2.15 amps at 130v that = 2.15 x 130= 279 watts

The other 100 volt lamp with a 32uf cap list

3.0 amps at 100v = 300 watts

My philips lamp says it runs on 13.8 amps at 100v that's = 1380 watts but the lamp says it's 1200 watts so what gives?

In the fine print they say there is a power factor corection for coil ballast of .86 What they list is the vaule that a distorted wave form will delever to the load. The real power for both systems should be real close to 250 watts.

I've got it . Thanks for the detailed information. I think it's just like cpu/fsb overclocking. Both ballasts are giving almost same output, however they use different multipliers, and fsb speeds.

Two different ballasts, not lamps
(I made that mistake also)


Yep, and you might find that a 130v ballast has a few compatibility (stability ) issues with a 100v lamp

I just found this, when I was researching about Osram HQI series' arc lengths ;



http://www.diy-community.de/viewtopic.php?t=10008

Me again. I have decided to not do this modification. Because, after this modification I will get ~25% light gain at all, and I will need some serious retouches in the case. Btw, heat and arc length issues are kind of drudging, unless I get huge light gain...

My supposition ;

Default (which has been overdriven) bulb gives : ~16.000 lumens (original value was 14.000 lumens)
250W bulb will give : 20.000 lumens

So I will be focusing on modifications of other PTV-01B users, to get an impression (still there is no reaction from LL projector users).

AV, the circuit is not as yours. The Cap is paralelled in the input plug... and th eballast is in series with the lamp. So the cap is in paralell with the ballast+lamp group. Here the effects of the diferent cap value are not exactly meaning diferent wattage on lamp... I am not sure but I was told the ONLY effect of the cap on those setups (like all of my gears here in EU) is to improve power factor.

What's your picture like using a 150W bulb? Is it pretty dim or can you see it fine?

Actually brightness (ansi lumen level) is quite satisfactory in a completely dark room. However it's not enough to me.

what do you mean by "ansi lumen level"... the stated 900-1200 value or your visual sensation...?

I guess you don´t have a luxmeter... my bet is somewhere 300 true ansi lumens

Yes, I meant my visual sensation.

BTW, your bet is quite right. Somebody measured PTV-01b's -real- ansi lumen level as "333 lux" ;

http://www.projektoren-datenbank.com/pro/i...eite=allyptv01b

That link talks about that measurement? (no idea of german)
(edit; please check that info, lux and lumens are not same thing...)

I belive it is bright enough for some darked room projections and taking into consideration image size ... just as the generic lumenlab projecotr. But what I will never understand is why the hell is 1200 lumens claimed. I believe there is no 1 in 100 projectors with 500 lumens even.

I have been plaiyng with the "spreedssheet" on the link... and would say it is based just on some calcs taking as the initial specs as trues. I wouldn´t say it is a real meassuremnt... let me play a bit more though...

edit;

just plaiyng with the "spreadsheet" it looks like it is based on 4/3 diagonal input.. work out the image area and work out the lux value so the total lumens remains constant (taking as true);

200 input

120*160=1.92m^2 @333 lux (average?)=639 lumens

100 input

80*60=0.48m^2 @1333 lux =639 lumens again.

300 input

240*180=4.32m^2 @148 lux= 639 lumens again.

4/3 to 16/9 increase...
9----16
120---X x=213 so 1.2*2.13=2.55m^2 for the 16:9 image at 333lux=851 lumens (somewhere closer to the 900-1200 claimed)

My projector is only putting out 100 lumens and is much brighter than that picture. How large is your screen. That makes a big difference in brightness.

phuton, still judging a brightness from a picture data?... I thought this was discussed several times...

Actually luminosity is "almost" same in the real life. So photo is very dependable for judgment. Picture size is ~78" (~200 cm) diagonal. I have also tried smaller screen sizes, however luminosity was not enough even with 50" screen (for me). BTW, I don't have a quality curtain yet, so I'm projecting it onto white (dirty) wall.