I've got a problem that hopefully someone can help me shed some light on.
I have an NEC HT1000 that's worked flawlessly for a few years now, with less than 400 hours on the lamp (it sat in storage for a while). I pulled it out of storage, and it wouldn't fire the lamp. I pulled the lamp, reseated it, and it worked fine for a few weeks.
I left it to sit again for a few weeks, and now it won't fire the lamp again. This time, the reseating trick doesn't work. I yanked the cover to see if the ballast was working. The bulb will flash sometimes, other times not (indicating there is an arc).
If I let the unit sit for a few minutes, it'll arc five times the first time the PJ tries to strike the bulb. If I try again in less than a minute it will either flash just once, or not at all. It will never flash/arc any other time it tries to strike the bulb (it tries to strike it three times before returning an error).
Is this just a problem with the bulb, and it needs to be replaced (despite having such low usage)? Or could it be a bad ballast? The former is easy to fix, the latter means a repair bill higher than the value of the PJ.
The lamp itself looks flawless, except for some odd coloration at the tip (the tip looks like it's supposed to be covered in tin/solder, but it seems like it's flaked off a bit with some brownish edges, exposing a white underlayer like porcelain).
Are there any good ways to check either the bulb or the ballast for correct operation?
I have an NEC HT1000 that's worked flawlessly for a few years now, with less than 400 hours on the lamp (it sat in storage for a while). I pulled it out of storage, and it wouldn't fire the lamp. I pulled the lamp, reseated it, and it worked fine for a few weeks.
I left it to sit again for a few weeks, and now it won't fire the lamp again. This time, the reseating trick doesn't work. I yanked the cover to see if the ballast was working. The bulb will flash sometimes, other times not (indicating there is an arc).
If I let the unit sit for a few minutes, it'll arc five times the first time the PJ tries to strike the bulb. If I try again in less than a minute it will either flash just once, or not at all. It will never flash/arc any other time it tries to strike the bulb (it tries to strike it three times before returning an error).
Is this just a problem with the bulb, and it needs to be replaced (despite having such low usage)? Or could it be a bad ballast? The former is easy to fix, the latter means a repair bill higher than the value of the PJ.
The lamp itself looks flawless, except for some odd coloration at the tip (the tip looks like it's supposed to be covered in tin/solder, but it seems like it's flaked off a bit with some brownish edges, exposing a white underlayer like porcelain).
Are there any good ways to check either the bulb or the ballast for correct operation?
easy troubleshooting
A repair tech would just swap lamps with a working projector (that uses the same lamp). That will tell you instantly where the problem lies. Difficult for the owner of a single projector!
I bet it is the lamp. Those are the parts with short lifetimes. Some fail in less time than that.
A repair tech would just swap lamps with a working projector (that uses the same lamp). That will tell you instantly where the problem lies. Difficult for the owner of a single projector!
I bet it is the lamp. Those are the parts with short lifetimes. Some fail in less time than that.
Thanks for the reply.
I guess what I'm just not understanding is how the UHP bulbs work. I keep thinking of it as a regular light bulb (even though I know they aren't -- they use arcs and UV light and stuff). When a regular incandescent burns out, the filament breaks, and you get nothing.
Would a bad bulb still arc when you try to strike/ignite it? I suppose I am thinking, that because I still SEE light coming from it, even for a moment, that somehow that means the bulb works. That may not be the case though, with UHP?
I'm also wondering why it will flash/strike 5 times sometimes, then just once or not at all later. Perhaps something is expanding and shorting out after it gets sparked?
If this wasn't a projector that I was going to sell/ditch in a few months anyway, I wouldn't mind buying a new bulb. Gotta save those pennies for a new Xenon-based lamp unit, though. 🙂
I guess what I'm just not understanding is how the UHP bulbs work. I keep thinking of it as a regular light bulb (even though I know they aren't -- they use arcs and UV light and stuff). When a regular incandescent burns out, the filament breaks, and you get nothing.
Would a bad bulb still arc when you try to strike/ignite it? I suppose I am thinking, that because I still SEE light coming from it, even for a moment, that somehow that means the bulb works. That may not be the case though, with UHP?
I'm also wondering why it will flash/strike 5 times sometimes, then just once or not at all later. Perhaps something is expanding and shorting out after it gets sparked?
If this wasn't a projector that I was going to sell/ditch in a few months anyway, I wouldn't mind buying a new bulb. Gotta save those pennies for a new Xenon-based lamp unit, though. 🙂
bulb failure
The part of an arc lamp that fails is the seal where the metal electrodes enter the glass tube. If one of those began to leak, then the gas inside the arc chamber would change over time. Everytime you run it, some of the gas would leak out as the pressure goes up. I think it could get to a point that the starting voltage would still jump across the gap, but the arc would not start.
Maybe somebody would like to try retrofitting your projector with a cheaper lamp? Anybody interested?
The part of an arc lamp that fails is the seal where the metal electrodes enter the glass tube. If one of those began to leak, then the gas inside the arc chamber would change over time. Everytime you run it, some of the gas would leak out as the pressure goes up. I think it could get to a point that the starting voltage would still jump across the gap, but the arc would not start.
Maybe somebody would like to try retrofitting your projector with a cheaper lamp? Anybody interested?
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