This is topic Basement LED Kelmar readers in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Cory Johnson (Member # 103) on 07-05-2000, 09:26 AM:
We just got some new projectors with the basement LED readers (reads both SR and Digital). My question is, we also have a Dolby Digital reader (DA20?) that sits on top of one of the projectors. That reader works well and runs between 0-5 usually on prints. Well on our new basement readers, we are lucky if we get readings under 5. On one particular projector, which has a new print of perfect storm in it, it runs at a constant 7. At every reel change splice, it drops to SR for a moment also. The other readers seem to sit at a constant 5 or lower except this one reader. We had 60 seconds in there and Shanghai Noon in there and both of them would drop out of digital during the show to SR for periods of time because the reader was showing 8-F on the meter. Are basement readers just not as good as the Dolby readers? Can they be adjusted? I think that tripping out of digital on a 3 weeks old print is not acceptable. If they can be adjusted, I want to make sure before I have our tech come in and redo the setup (The theatre is 3 weeks old with all new equipment). Thanks.
Posted by Ken Layton (Member # 133) on 07-05-2000, 09:51 AM:
Your basement reader must be a Kelmar.
Posted by Gordon McLeod (Member # 33) on 07-05-2000, 11:18 AM:
What make of projectors and what make of readers. Are the used projectors
Often it can be bad bearings in the soundhead that cause excessive jitter that create problems in the basement readers
Posted by Cory Johnson (Member # 103) on 07-05-2000, 01:05 PM:
They are brand new X90 Strong Projector Consoles with Kelmar basement readers (dont know the model, but the came built-in with the projectors.) They are the dual Analog/Digital LED readers with two lenses - one for SR, one for SRD. Everything is brand new out of the box: CP500, X90 Projector, QCS Amps, QSC Digital booth monitor with built in cross overs. We have four new booths will identical equipment and it is just one of the new projectors that is having this issue of bad digital reads.
Posted by Dave Cutler (Member # 515) on 07-05-2000, 02:11 PM:
Run a cat 69T (Dolby Tone). Make sure that the reader is calibrated correctly. May need a power boost to the LED. May also be out of alignment.
Posted by Joe Redifer (Member # 3) on 07-05-2000, 02:17 PM:
At least your basement readers work. Mine are Christie and it's a whole different ballgame.
Posted by Ari Nordström (Member # 288) on 07-05-2000, 03:08 PM:
My experience is that the Dolby readers (probably Cat 700 or 701 in your case, BTW; DA-20 is the digital processor) are slightly better than the combo readers. Our cat 701 usually stays between 0-3, with an occasional print at 4 or 5. So far I haven't had more than one print that went to F. It turned out that the subtitles had wrecked the SRD track.Among the basement readers i've seen or heard about, Kinoton's reader is supposedly an absolute disaster while Cinemeccanica's newer readers are actually quite good. Kelmar, I don't know much about, I'm afraid.
Posted by Stephen Jones (Member # 16) on 07-05-2000, 08:46 PM:
I find the Kinoton is one of the best basement readers I have used and the other being the cat 700.Our error rate on the Kinoton reader's is always between 1 and 3 which I think is pretty good as some cat 700's have been on 5 or 6.I have used the Component Engerneering reader fitted to a Century sound head and that was usually on 6 or 7.As for Cinemeccanica sound heads I'm not impressed by these at all.Stephen
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Posted by Joe Redifer (Member # 3) on 07-05-2000, 09:52 PM:
Does anyone know why the Christie basement readers are so horrible? I mean, besides the fact that they aren't designed well, aren't supported by Christie, and that their projectors shake them all over making them 'seem' even worse.If Christie supports their basement readers, then they will surely correct my comments for everyone to see. (They do read this forum)
Posted by Brad Miller (Member # 2) on 07-06-2000, 03:26 AM:
Joe,Doesn't the fact that Christie has ceased selling their basement readers pretty much answer that one? Dealing with these has become a small war as you more than well know. The key word here is "support" from Christie. The answer is of course to admit fault and send over penthouse readers. Will they? Who knows, but you can damn well bet with the fights I've had with their readers getting them to track acceptably, any half-assed solution will be WELL documented here. Perhaps on every page of the site! People must know. Do I see a Joe basement reader review coming?
I've not had problem one with a Dolby penthouse reader aside of having to realign one that was dropped and although I've never used Kelmar's basement readers, the Component Engineering I have set up and aligned tracked very well in a Simplex with no problems of any sort.
I have been quite pleased with the results from Kelmar analog-only readers though and have installed many of them. (I prefer to install analog-only readers with a Dolby penthouse...not basement combo readers.) Out of all the ones I installed, I had one bad cell and one bad power supply and Kelmar overnighted replacements at no charge. Now THAT's backing a product!!! Their product is good and with that kind of service, I will continue to recommend them on all my installs.
(Incidentally, I have consistently found that with Kelmar's power supply set to it's absolute minimum output setting, the preamp gains on the processor always are no more than 3 turns from zero to get the signal DOWN to Dolby level. That leaves an awful nice room for turning up that led as it ages. 
)
Posted by Dave Cutler (Member # 515) on 07-06-2000, 10:25 AM:
How long should an LED last in a basement reader. My theatre is about 2.5 years old and a few of the LED's I have had to crank all the way up. Some still aren't at Dolby level. I have Component Engineering readers for both analog and SRD.Am I doing something wrong? Or do they just age like the SDDS LED's which I have heard need to be replaced about every 3 years.
Posted by Brad Miller (Member # 2) on 07-06-2000, 01:57 PM:
I wonder if your CE leds were installed with the power supply set at "half" to begin with, effectively killing your useful life.I find SDDS leds must be changed every year and tweeked every 3 months to keep them running.
Posted by Ari Nordström (Member # 288) on 07-06-2000, 03:10 PM:
Stephen,The Kinoton readers I heard about are all installed at one single multiplex in Stockholm. According to one of their projectionists, they have had very few SRD shows without drop-outs, and quite a lot of them had so many that it was pointless to run the sound digitally at all (unless DTS discs were available).
As for Cinemeccanica, the older combo readers weren't particularly good, but a recent update I saw and experienced impressed me enough to force me to reconsider. They aren't as good as Dolby's, though.
Posted by Gordon McLeod (Member # 33) on 07-06-2000, 03:47 PM:
Moral of the story
BASEMENT READERS SUCK but some Suck more than others
Posted by Joe Redifer (Member # 3) on 07-07-2000, 03:51 AM:
But Gordon, what about the Christie readers? The projector has that 'Christie Quality Control' sticker on it, so that means everything in the projector is quality assured, right? Quality is definitely assured. Not necessarily good quality....
Posted by Kevin Crawford (Member # 469) on 07-07-2000, 01:49 PM:
Dave,For the analog, Component put resisters in the reader. The resisters cut the gain from them. Do not ask me why they did this. I have yet heard a good reason why. You should take the analog reader out and cut the resisters. There are two. They are just two metal jumpers on the circut board. I believe they are J5 and J6.
As for the Dolby basement readers. They seem to come in batches of good and bad. I have had to replace some that were brand new and others not at all. They mostly run between 3 and 5. There is one that I have seen that runs at .5 and 1. That was on Titantic after 5 months. That was impressive. Most of the readers I have replaced were due to operator neglegence. For some reason these people believe that oil needs to coat the outside of the machine as well as inside.
Posted by John Wilson (Member # 269) on 07-08-2000, 02:25 AM:
.5 and 1? That's pretty impressive. We're running a couple of trailers now that were at 7. and 8 right out of the box. (But that's trailers, not a feature.)Our print of Gladiator (Italian from memory) had a 6 error rate from day one, again brand new but the dolby digital track was marked on every reel.
Yes, cut the resisters on the analogue. Our digital leds are fading and will need replacing soon (Just over two years old).
Posted by Pat Moore (Member # 380) on 07-08-2000, 07:09 AM:
I think Dolby had a service bulletin out regarding the resistors on the reader assemblies, and Strong put one out as well last year some time. That service bulletin would be on our website (www.strong-cinema.com) -- sorry I don't remember which one it is but you can find it easy. Cutting those two jumpers increases the gain from the analog reader. Basically you get all you can from the reader and processor preamps, and that allows you to lower operating current of the LED's big time.
Posted by Gordon McLeod (Member # 33) on 07-08-2000, 11:39 AM:
Yes Joe that sticker says it all, the reader met the same quality standards as the rest of the christie projector
Posted by Dave Cutler (Member # 515) on 07-09-2000, 12:47 PM:
Brad, (or anyone)How should the power supply be set when installing new LED's on a CE?
Posted by Pat Moore (Member # 380) on 07-09-2000, 02:13 PM:
Dave;
Take a look at the service bulletins on the Strong website (www.strong-cinema.com); the procedure is outlined there. Dolby's and CE's site might have the info as well. Basically, you just about max out gain from the processors preamp and then use LED power to get to Dolby level.
Posted by Gordon McLeod (Member # 33) on 07-09-2000, 02:59 PM:
The problem with maxed out gain is that you are also amplifing noise.
CE has a method of setting the current using a amp meter
Posted by Brad Miller (Member # 2) on 07-09-2000, 03:17 PM:
I'd be interested in CE's method for setting the level. As I stated earlier, I get so much light from a Kelmar, it's power supply must be all the way down as well as the preamp gains when the led is brand new. That's fantastic! (Of course, this requires the led be aligned absolutely precisely...but that's the whole point.)Otherwise, I generally set the preamp gains about 1/2 up. The trimpots are 18 turns, so turn them up until they start clicking and back off about 9 turns. Then roughly set Dolby level with the led's power supply and then tweek it with the preamp gains. I'd be interested in other people's recommendations (always looking for a better way to do things ), but that's how I've been doing it with excellent results.
Posted by Mark Gulbrandsen (Member # 72) on 07-09-2000, 10:01 PM:
I have never had any trouble with Kelmar basement readers except for one defective LED that had several segments out. There is no reason that they should not be able to be aligned to work as good as the competitors. One thing for sure....the LED bracket is a whole lot beefier and solid than CE's is. I do prefer the Cat 701's to anything else out there but all basement readers in general should work fine IF THE PROJECTOR IS OPERATING PROPERLY!!!
Mark
Posted by John Wilson (Member # 269) on 07-10-2000, 02:23 AM:
Mark, are you back at work yet? Could you organise those prices we spoke of? I emailed the office but no reply as yet...
Thanks