Is this definitely the bulb on projector?

GinG

GinG

GinG

Soldato
Joined
22 Jul 2006
Posts
7,719
Hi All,

I have inherited a Panasonic PT-AX200e projector after my grandad sadly passed away last week. I know it was due a replacement bulb as the last one was a Chinese import, however I just want to check it is actually the bulb and nothing else. You can see in the pic below the dark circle in the middle.

Cheers

 
I've personally not seen a bulb dim like that only in the middle, it could be panel/filter damage. But probably not :p. Get a new bulb.
 
Thanks Guys.

When playing a movie that area actually has a yellow tinge. Maybe could have been a faulty bulb from the off?
 
GinG said:
Thanks Guys.

When playing a movie that area actually has a yellow tinge. Maybe could have been a faulty bulb from the off?
Click to expand...

Sorry to be the bearer of bad news, but from the picture and the description and the fact that it's an LCD projector then I'd say that this is polarizer damage. If that's the case then the projector is toast.

There a couple of simple tests.

First, if this is in the plane of the lens then it should be possible to focus it better. It'll never be sharp but rotating the focussing ring should make it less blurry. If it can't be focussed up then it's not in the final light path from the LCD panels to the projection lens.

Second, the projector has a VGA input I'm sure. Generate some primary colour test patterns - Whole screen of pure red. pure green and pure blue. If you see this splodge on one colour pattern only then it's not in the lens. It's in the light path before the LCD panels. So it's either in the collimater (the fly-eye lens used to focus the light in to a single direction) but that would affect all three colours, or it's in the UV filters before the polarizers. Whichever colour test pattern shows the image blob, then that's your polarizer and UV filter that's fried.

The lamp emits broad spectrum light which includes Infra-red (heat) and UV (does bleaching damage). This happens with all lamps including manufacturer own brands (Philips/Osram) but more so with the Chinese copy lamps because the lamp glass allows more UV to pass. Most of the UV light is dealt with by the projector's UV filters which sit between the light prism (splits light to red, green, blue) and the LCD panels. With projectors the age of the Panasonic AX200, the UV filters were made of an organic substance. Over time that substance degrades. It allows more UV to pass and that then burns the polarizers. The wear pattern starts from the centre because that's where the heat built-up is greatest.

I wouldn't rule out a damaged lamp caused buy bad fitting technique. Touching the glass surface will leave skin oils on the glass. This clouds up under the action of heat. That's why you need to wear gloves and take care not to touch the lamp glass. But my money is on burned UV and polarizer filters on the blue channel.
 
Last edited:
Hi Lucid,

Thank you very much, very interesting post and will give it a try.

If I remember correctly before the cheap bulb was put in all was fine, as soon as this bulb was fitted this 'halo' appeared. Unfortunately I wasn't the one who fitted and by the time I noticed was too late to return the bulb.

Will run a few tests and see what happens.

Cheers
 
No idea tbh, id guesstimate at about 1600. Not a massive amount and on the original bulb too!

If you're z3 is still going strong at this point you're pretty lucky I say, must be nearly 10 years old now? Great pjs it's a shame Sanyo more or less left the market.
 
I know not the best quality but I think you can see the spot in all the colours, think I will get a new bulb just to rule this out before it goes to the tip if it does indeed prove to be anything more sinister.



 
Chris1712 said:
No idea tbh, id guesstimate at about 1600. Not a massive amount and on the original bulb too!

If you're z3 is still going strong at this point you're pretty lucky I say, must be nearly 10 years old now? Great pjs it's a shame Sanyo more or less left the market.
Click to expand...

No don't say that :( That's how old it is & it is on the original bulb (no idea how many hours on the bulb though). I guess it would give me an excuse to buy a 1080p model then.
 
GinG said:
I know not the best quality but I think you can see the spot in all the colours, think I will get a new bulb just to rule this out before it goes to the tip if it does indeed prove to be anything more sinister.
Click to expand...

Have you tried the other troubleshooting steps in lucid's post?
 
GinG said:
P.s can I not run the tests using hdmi?
Click to expand...
If you have a laptop with HDMI out, then sure. Have you got a laptop with HDMI out?

GinG said:
I know not the best quality but I think you can see the spot in all the colours,
Click to expand...
Can you?

I know I'm only looking the pictures you posted whereas you're there with the actual projector; but to me it seemed from the first blob image that it covered 3/4 of the width of the screen. If that's the case, then I'd expect the blob to be in the same space as the green bar in your test pattern. From what I can see though, the green bar seems unaffected.

Where the blob is seen is in blue, and in white. Remember, white is made up of red, green and blue light. So any problem on the blue panel would show on the blue bar and the white bar but not the green or the red. That seems to be exactly what your pattern shows.... and it's what I predicted.
 
lucid said:
If you have a laptop with HDMI out, then sure. Have you got a laptop with HDMI out?

Can you?

I know I'm only looking the pictures you posted whereas you're there with the actual projector; but to me it seemed from the first blob image that it covered 3/4 of the width of the screen. If that's the case, then I'd expect the blob to be in the same space as the green bar in your test pattern. From what I can see though, the green bar seems unaffected.

Where the blob is seen is in blue, and in white. Remember, white is made up of red, green and blue light. So any problem on the blue panel would show on the blue bar and the white bar but not the green or the red. That seems to be exactly what your pattern shows.... and it's what I predicted.
Click to expand...

It may be just my eyes making up the fact I can see the slight tinge in the other colours...looking again at the pictures your right it just looks like the blue is affected.

I can focus the lens no problem as you said in the previous post so possibly could be death of the projector, just strange how it happened as soon as the bulb was changed however.
 
Well lucid, took the projector apart and your correct, as seen below you can clearly see the burn on the blue polariser.



Going to have a read up on the web about the replacement but what a shame! Does this just happen with age??
 
You must log in or register to reply here.
Back
Top Bottom