One out of five times I turn the lamphouse on, the contacts in the power supply actuate, but there is no ignition pulse. The lamphouse will just sit there for a few minutes until it decides to ignite. The emergency ignition switch on the ignitor will not strike the lamp. I have checked all of the circuits for proper voltage as described in the manuals for the lamphouse and power supply, and everything's okey dokey. Open circuit voltage over 110VDC, 115VAC control voltage, all interlocks happy. Connections all clean and tight.

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Good question above from Pete -- do you get a flash across the lamp or literally nothing from the manual igniter switch? When the systems do light, is all "normal" in terms of operating current & voltage, light output, etc? Is the situation different if the systems are warm or cold?

You mentioned two lamphouses started to do the same thing. At the same time? One night everything's fine and then it changed the next day? If that's the case, I tend to think it's something outside the systems -- whatever that might be. If it's been a gradual change, then it could be two systems aging gracefully together.

What power supply? That 110VAC sounds a little low depending on the supply itself, especially if you're not getting ignition pulses. That open circuit voltage would generally build up to at least 125-130VDC or higher. However, that shouldn't change the action of the manual igniter switch -- it doesn't care what the open circuit voltage is as long as there's AC power to it, and since the contactor is closing in the supply we know there is.

Checking connections is a good idea -- not only in the lamphouse, but back to and inside the power supply as well.

The obvious one might be the xenon bulb -- how many hours on them? Have you tried switching lamps between the two systems, or installing a new one?

Pat

Still wierd that it could be the same on two systems. Which might be understandable if the AC Power to these two power supplies comes through a single feed, you might be losing part or all of a phase there. It would be terrible practice to wire AC Power that way, but I've seen it done before. Put a voltmeter on the AC input to the supply and be sure all three phases are equal. If one is low, there's your problem.

I literally get nothing from the manual igniter switch. All is normal when they do light (voltage, output, etc.). No difference between warm or cold... this is truly an intermittant (sic) problem.

>You mentioned two lamphouses started to do the same thing. At the >same time? One night everything's fine and then it changed the next >day? If that's the case, I tend to think it's something outside the >systems -- whatever that might be. If it's been a gradual change, >then it could be two systems aging gracefully together.

They both do the same thing, but not at the same time. Sometimes I won't see the problem for months, other times it'll be a pain for a week on only one projector and then go away. They are the same age and have always been together and are only 1 digit off at the end of the serial number.

>What power supply? That 110VAC sounds a little low depending on the
>supply itself, especially if you're not getting ignition pulses.

The power supplies are Strong 61001-4 's.

>The obvious one might be the xenon bulb -- how many hours on them? >Have you tried switching lamps between the two systems, or >installing a new one?

The 1600W lamps are at about 100 - 120 hours, and the old lamps were normal at the end of their life (about 1500 hours). They did the same thing with the old lamps.

Which brings us to the AHA! moment.

>Still wierd that it could be the same on two systems. Which might be >understandable if the AC Power to these two power supplies comes >through a single feed, you might be losing part or all of a phase >there.

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Those supplies will run 2kw as well as 1600W. I forget the combination and I don't have a manual handy, but I think there were three primary taps (190, 208 and 230). Seems like there was a secondary set as well, X1 and X2(?). The incoming voltage and output wattage determined the combination of leads to be used. If you're reading 208 but the supply is tapped for 230, that could cause a little problem like the low open circuit voltage you are reading. You might check the manual for that supply and see what it says.

Another thought -- the older Strong supplies used large tap switches for fine adjustment of operating current. Could be those contacts are dirty, corroded or loose. A little contact cleaner and running the switch through its positions might help that.

Still doesn't explain why the manual igniter doesn't make things happen. There is a cover safety switch on the igniter black box itself. If the cover is loose or the switch is getting intermittent, that would stop any ignition try.

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Clean out any dirt or carbon-paths in the gap assembly and make sure the points are set correctly. (And all leads are properly insulated and isolated from shorting out) Also, many early versions of the igniters had a problem with the HV-coil potting insulation cracking and causing the HV to leak off.

Be careful of that f*cking HV cap. Even though the igniter is removed from the lamphouse, a good cap will hold a several-thousand-volt charge for a long time. I speak from experience... YIKES!

Remember, the igniter is a Tesla coil and for it to work and generate HV, you need to create a RF-rich spark in the spark gap.

>>> Phil

Steve

Pat, what is the recommended gap in his situation?