Also, do the little pots on the side of the tree have anything to do with the payout speed, or are they only used to adjust the takeup speed?
No, the trim pots that are located on the side of the tree will NOT help your problem. Those trim pots are for the setting of when the take up rollers will activate the take up motor or the brake. (This is what I was told) I have checked the LED at the end of the platter arm, I did find that some of them were dirty with metal shavings from the brain stem, I cleaned it and it seemed to help. What I had to do, was buy 17 T-Handled allen wrenches so each platter has a wrench to adjust the brains during show. Most of the time, we just leave the wrenches in the brain during the show to adjust them at the first sign of trouble. I hope that our tech guys can get this fixed. I gave them 12 brains to be sent back to Big Sky for replacement. I think the problem is that light/dark sensor tape on the base of the brain stem. It seems to get dug up during the change. I asked Big Sky to send me just those tapes so I can replace them, but I am still waiting for them. If you can find a solution let me know, and I will do the same.
If you dont have the manual, I will get mine scanned and send it along to Brad so he can add it to the manual list.
Thanks for the info. I, too, am glad I am not the only one having the problem. I don't like the idea of averaging the brain for all three platters. Until I can get the problem completely corrected, what I think I'm going to do, if it's ok with my manager, is calibrate one brain for the problem platter and put a note on it saying that it is to be used only on that deck, and calibrate the other brain for the other two decks. I work at a 16-plex, and there are currently at least 3 platters systems I know of that have this problem. I don't think it is the sensor tape, because the problem happens with any brain. I have a feeling it is the sensor inside the arm. But I'll leave that up to my tech. BTW, I do have the manual.
And our favorite new Big Sky story is about a platter that turns clockwise, but only when running from the MUT.
Yes, I agree, micro swtiches are so much easier!!!
On the subject of microswitch platters, I think it's really funny how on that other thread where everyone was saying how brilliant Strong microswitch platters are, I jumped in and mentioned how similar the ORC "Super Platter" was. Then all of a sudden everybody got really really quiet! Christies sound much simpler to deal with than these Big Sky platters.
At my last place we had one wrap forward at full speed for about five minutes before the wrap detector finally shut it down. The cause? The sensor arm became stuck in the full-on position due to being caught on a pealing sticker under the arm (the sticker has the threading path printed on it).Judging from the two installations I've seen in town, I think Big Sky's quality control has fallen off a lot lately. The Brenden Palms 14 has had very little trouble with their platters (the MUTs were another story), whereas poor Crown Neonopolis 14 had almost nothing but trouble with theirs, at least initially. The two installations were only about six months apart. The guys at Crown ended up having to do a lot of "field engineering" to get their platters running smoothly--work that should have been done at the factory prior to shipment IMNSHO.
Ogenki de,
Paul
SMPTE Hollywood Section
Mercenary video/16/35/70mm/IMAX projectionist
"Otaku wa tsurai yo" <- Yeah I know, bad pun. Sue me.
It's tough being a fan!
We have a Big Sky platter. It is wonderfully reliable. One of the major points about it is the fact that IT DOES NOT REQUIRE TIMING!
The pay out is powered without regard to the takeup and therefore need not be "timed" at all.
The simple adjustment of the brain is for the point at which the sensing arm causes the platter to begin rotation. From that point on, the arm causes the speed to increase, decrease or even BRAKE if necessary.
Please go to the Big Sky page and see a demonstration of how a potential brain wrap 'repairs itself' in less than a minute. This simulates what could happen when you forget to take the adhesive off the second wrap from the beginning of a reel and it draws the film in toward the brain.
The platter system 'knows what you have threaded it to do' and the payout does not operate until the projector calls for film.
If you have trouble with any manufacturer's equipment, the best way to get the straight story is to call the builder. They have everything to lose when people start to talk without information.
Soap Box returned under the lamphouse!
KEN
I agree with you on this, but my problem is if I set the brain for lets say the top platter, then use the same brain in the second platter, I will have to re adjust the "point" because the brain will not payout or it will payout to fast causing a brain wrap.
I have 10 pages of adjustments our staff have logged over the last two months. This log shows what platter number, brain number (I numbered the brains) which deck needed the adjustment, and what the platter was doing. Over/Under wrapping. Adjustments are only done if the operator notices a brain wrap in the making or feels that the film could be scratched if adjustment is not made. After about one week, I noticed the pattern above starting to develop. I told this to the Saleman to his face in our projection booth, and all I got, was to average the brain to all three platters. Adam can tell you, I was NOT a happy camper after this guy had left our theatre. So, I have taken the problem to the builder, and still am waiting.
You are on the right track. When I called Big Sky to ask a few questions before making the purchase, I talked with the first person to answer the phone and he was a practicing engineer. He also owns several screens which are equipped with Big Sky products. He has both a theoretical and working knowledge of the product. I am sure that you will receive a solution for your problem. The earlier platters were equipped with different parts where the brain stem is inserted into the deck. The biggest problem with the entire system is that the operator inserts the brain at an angle so that the 'grey scale' coding on the stem becomes marked or damaged. I can believe that if yours is marked that all readers do not all "see the same area" of the control strip and therefore can read the marks as black. The resulting symptoms would likely be
1 Speed control during payout is erratic (jumpy and too fast or slow)
2 Adjustments do not correct this problem on all decks
3 A vast difference in performance between decks using the same brain
First: Contact the service department at Big Sky and describe your problem as completely as possible (not all field sales people are engineers)
Second: Examine carefully your 'grey scales' and compare a working one to the erratic one (looking for scratches or dark scuff marks)
Third: (and also First) correct the way you insert the brain stem so you are not damaging the control strip in the insertion process. These brains are very reliable when proper care is taken to insert them properly.
KEN
quote:
"Remember that both motors will be slowed during make-up, but only the table motor will be slowed during break-down, as the platter motor is dis-engaged, and the deck is spinning free."
From what I saw at ShoWest it seemed to be a fairly good platter with only minor design flaws, but I didn't know about this. That pretty much kills it right there and the platter would get an automatic "F" rating in a review. They have designed proper backtension from the reel when making up a film, there is no excuse for not designing proper backtension during breakdown. Film handling NOT done right.
By the way, who are you guys talking to at Big Sky that are not solving your problems? I know they know about this forum. It would only make sense for their business to assist people in the field with their product as issues like this turn up. I certainly am getting a very bad impression about the company reading these complaints and one tech who represents the company blew his top a couple of weeks ago for no reason at a Dallas theater. (I could say more, but I won't. The guy is getting a bad enough reputation around town as it is.)
Anyway, surely there is some tech from the company that could be their internet spokesperson to assist people. Many company techs and corporate people get nothing short of furious if theater managers and projectionists call up a manufacturer to inquire about minor problems, so the need for online representation IS quite important to keep their equipment running properly through the spread of proper instruction. If projectionists and managers cannot get the kind of information they need to operate or maintain any piece of equipment properly, then that equipment WILL fail prematurely as it is misused because of the operators playing guessing games on how to adjust and run it.