The lamp in Fortuna #1 is going intermittent on the operators there. It apparently will run normally for about an hour and a half, then it will shut off, remain off for between 1 min and 15 min(this time period is apparently the same every time) and then just turn back on and run for a while longer, and repeat the off-on process. Heres the stats:

Strong Super-80 lamphouse with Osram 4000W bulb (bulb has approximately 300 hrs on it and does not flicker and strikes easily).
Strong [non-switching] power supply model 78002-01.

Things I have already had them do (This theatre is a 4-hour drive from me and i wanted to get as many of the 'duh' things eliminated before making the trek):

-This problem is occurring both in automation mode and in manual override (ruling out an automation problem)

-The cooling fan is running at full speed, and is running when the lamp quits.

-When the lamp is running, all current and voltage readings are nominal.

-The inside of the power supply and the vents on the sides of the supply have just been cleaned out to maximize airflow through it for good cooling. They report very good airflow through the power supply case.

-I asked if there were any reports of smoke or any smells. One projectionist did say that he smelled a 'burning plasticky smell' when it cut out on him this weekend, however he reported about an hour ago that he cannot smell anything out of the ordinary now.

I have not as of this writing had them check the lampohouse blower, and there is the possibility of the blower vane switch causing this problem, but the fact that it will run fine for an hour and a half before cutting out has me puzzled. This I will be checking with them ASAP.

-I also do not know if the contactor is remaining closed when the lamp quits, this also will be checked out tonight if possible.

Any help, as usual would be greatly appreciated.

Aaron

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Of course these cheap thermal cutout switches have been known to go bad as do the microswitches on the lamphouse bulb cooling fan.

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The thermal switch, if memory serves, is an 88118, same as the one used in the smaller 61000 series.

If it is the thermal, and they are in the booth at the time, they should hear the contactor kick out, and in again when it re-starts. (Of course, I know you already knew that!).

Or is it? I have been told that after the first show last night had the problem occur twice, the following two shows ran without a single lamp outage! Maybe there is something else?

If the problem continues with the sensors bypassed, next up is the blower vane switch on the lamphouse, followed by the contactor.

Aaron

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Thanks again, i will remember all the suggestions when I finally get up there.

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