If you attended the Milford Drive-In Theater on June 20 or June 27, 2009, you are probably aware that we had a projection problem on Screen 1.
First, on behalf of the Milford Drive-In and myself, the projectionist on duty those nights, let me apologize to those patrons affected by the problem.
Occasional mechanical issues are inevitable, but two weeks in a row is extremely unusual. As you can imagine, we've been getting plenty of email and comments about the problem. I'm writing this article so that everyone knows exactly what happened, what we did about it and improvements we are making. This article is going to get a little technical, but that's necessary so that everyone clearly understands the whole story.
On Saturday, June 20th, while starting the 2nd movie on Screen 1, the projection lamp failed to light. This 5000-watt high pressure xenon bulb normally lights up about 7 seconds prior to the image being projected on the screen. As I pressed the start button, I heard the usual high voltage arcing (a sizzling sound that lasts about 1-second) followed by a loud boom, as the projector began to run. I knew there was a problem so I immediately pressed the stop button. My first thought was that the bulb exploded. Xenon bulbs are pressurized to about 150 PSI when cold, but when they are at operating temperature, the pressure can exceed 600 PSI. Exploding bulbs don't usually happen unless the bulb has exceeded it life expectancy (800 hours) or there are finger prints on the bulb (we use gloves to change the bulb).
This is a picture of a Xenon Bulb used in our projectors. The bulb is approximately 16 inches long and is 5000 Watts for Screen 1 or 6000 Watts for Screen 2. |
Upon checking the lamphouse system, two circuit breakers had tripped. I opened the lamphouse and checked the bulb visually to verify that it did not explode. All looked OK, so I closed up the lamphouse, reset the breakers and tried again to re ignite the bulb. This time there was no sizzle sound, indicating that there was no ignition voltage. The bulb normally requires 35 Volts DC and 140 Amps once lit. It requires 40,000-50,000 volts to ignite. The lamphouse volt meter indicated that the lamp power supply (rectifier) was working, so I felt the problem was being caused by a failed igniter. Fortunately we had a used, but functional one, but it takes time to change it.
Because the expected repair time would have been at least 1 1/2 hours, the decision was made to cancel the 2nd film.
During the 2nd film on Screen 2, we changed the igniter and that did not solve the problem. Although there was no indication that the bulb had failed, we changed that also. Ultimately, after some tedious troubleshooting on Sunday morning, the problem turned out to be a bad igniter, relay and circuit breaker. This resolved the problem and the show ran as scheduled from Sunday through Saturday, June 27th.
Because spare components are not readily available, after talking to our projector tech and the owners, the owners then ordered a new Lamphouse, Bulb, and Rectifier. This was ordered on Sunday, June 21st, on an expedited basis with an expected delivery time of 10 days. I should add that the new lamphouse increases our illumination to 6000 Watts, and will be an exact clone of what was installed on Screen 2 four years ago. When I first started working at the Drive-In, we only had 4200 watts of light. We increased it to 5000 four years ago. With 6000 watts, we'll probably be needing sunglasses!
After 6 days of successful operation, at the beginning of the show on Saturday, the same problem occurred again. No high voltage sizzle, but instead a loud "boom" and the sound of tripping breakers. I performed the normal troubleshooting procedures and found two tripped breakers. One breaker reset but the other one, the 1/2 amp igniter breaker, would not reset. I started the show on Screen 2 and then made the announcement on Screen 1 that we were having a technical issue that we were trying to resolve. Since the circuit breaker was obviously defective, I wired in a fuse to bypass the circuit breaker, figuring that if I could get the bulb lit, we could get in both movies. Needless to say, the fuse blew so I knew this screen was not going to run that night.
I advised the owners. After a brief discussion that included;
The choice was clear that we needed to run Transformers/Star Trek and cancel UP/The Proposal. Technically UP was the co-feature even though it was shown first (because of the rating) and The Proposal was programmed to play with Transformers on Wednesday 7/1 and Thursday 7/2. As you can imagine, regardless of which one we cancelled, not everyone was going to be happy. I should also mention that we even considered running UP first and then Transformers, but decided that it would be a violation of our license.
I announced the decision, told everyone to switch screens (which happened faster than I could imagine) and told the people on Screen 2 that they had two choices... Watch Transformers/Star Trek, or proceed to the Ticket Booth. One owner and two Concession workers were immediately dispatched to help the ticket person deal with the problem. The other owner left the lot to help me with the film transfers.
This picture shows the lamphouse that failed (left) and the film platters for each screen. It's an older picture that doesn't show the new lamphouse on Screen 2 (behind me). |
Switching the first features on both sides turned out to be a very difficult problem. Screen 2 was already 8 minutes into the Intermission portion, so the film had to be unloaded and hand wound to get the approximate 800 feet of film back onto the platter. Because the center ring of the film pack was already removed for showing and couldn't be reinserted, we couldn't switch the film the traditional way... by clamping it, normally a 5 minute process per film. We had to move the whole film platter from one side to the other. This involved removing the platter drive motors and the platter payout mechanisms (brains), and then lifting the platter carefully off of it's axle.
On Screen 1, we had a similar problem. About 100 feet of film had to be hand wound back onto the platter. Because of the length of Transformers and the Intermission film, (15,030 feet) and the center ring was also removed, we had no choice but to move the whole platter to Screen 2. Moving platters is extremely risky, since the film can easily slide off center or the pack may elongate which can cause the platter to throw the film onto the floor during the movie. Normally, we would have wound off the film onto 6000 foot reels and then wound it back onto the other platter, but we cannot do this when the center ring has been removed.
Despite all of the problems above, we had Transformers on the screen within 40 minutes.
We are expecting the new lamphouse, rectifier and bulb to be installed on Tuesday, 6/30, pending no delivery problems. We are expecting to resume operation on Screen 1 on Wednesday. Check the website or the theater recording (603-673-4090) for an update on Wednesday.
We hope you understand our reasoning for doing what we did. While I would like to say that it won't happen again, it's inevitable that there will be an occasional problem, but we'll do our best to keep them to a minimum. Both Dick (the other projectionist) and I have more 40 years experience each as projectionists. We both take our jobs very seriously!
Thank you again for being a Milford Drive-In Theater patron as well as your patience and understanding while we perform this necessary Repair/Upgrade!
Update - 6/30/09 - 9:00 PM:
The Lamphouse, Rectifier, and Bulb upgrade has been completed. Normal show schedules will resume on Wednesday 7/1.